Airend Failure Modes & Failure-Mechanism Engineering

AIREND FAILURE MODES & FAILURE-MECHANISM ENGINEERING

It requires noise, vibration, temperature, oil debris, carryover, loss of capacity and trip history to be correlated with inspection findings; distinguishes bearing failure as a possible consequence of contamination, lubricant condition, misalignment, overheating or operation outside limits; requires failed parts, photographs, lubricant samples, bearing/seal condition and debris to be preserved; and requires immediate escalation where rotor/element contact, abnormal metal debris or severe vibration could worsen damage or make continued operation unsafe.

Its authoritative body remains separately preserved.

Provisional new-series slug: /compressed-air-engineering/airend-failure-modes-failure-mechanism/ | CTA: Request an Evidence-Based Airend Assessment

The symptom is not the failure mode. the failed component is not automatically the root cause

Noise, vibration, heat, oil carryover, loss of capacity, abnormal debris or a trip can indicate internal distress, but each can also originate elsewhere in the compressor package or system.

The engineering task is to preserve and correlate evidence, identify plausible physical mechanisms, recognise consequence-versus-cause relationships, and stop operation where continued running could convert a repairable condition into major rotor/housing damage.

1 — Compressor Identity

Failure-Mode Governance: govern compressor identity as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

2 — Airend Identity

Failure-Mode Governance: govern airend identity as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

3 — Hours

Failure-Mode Governance: govern hours as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

4 — Duty

Failure-Mode Governance: govern duty as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

5 — Pressure History

Failure-Mode Governance: govern pressure history as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

6 — Failure Timestamp

Failure-Mode Governance: govern failure timestamp as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

7 — Operating State

Failure-Mode Governance: govern operating state as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

8 — Symptom Chronology

Failure-Mode Governance: govern symptom chronology as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

9 — Service History

Failure-Mode Governance: govern service history as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

10 — Lubricant History

Failure-Mode Governance: govern lubricant history as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

11 — Recent Work

Failure-Mode Governance: govern recent work as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

12 — Recent Process Change

Failure-Mode Governance: govern recent process change as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

13 — Criticality

Failure-Mode Governance: govern criticality as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

14 — Technical Reviewer

Failure-Mode Governance: govern technical reviewer as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

15 — Revision Control

Failure-Mode Governance: govern revision control as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

16 — Noise

Symptom Evidence: govern noise as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

17 — Vibration

Symptom Evidence: govern vibration as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

18 — Temperature

Symptom Evidence: govern temperature as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

19 — Oil Debris

Symptom Evidence: govern oil debris as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

20 — Oil Carryover

Symptom Evidence: govern oil carryover as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

21 — Oil Consumption

Symptom Evidence: govern oil consumption as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

22 — Capacity Loss

Symptom Evidence: govern capacity loss as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

23 — Pressure Change

Symptom Evidence: govern pressure change as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

24 — Motor Current Boundary

Symptom Evidence: govern motor current boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

25 — Trip History

Symptom Evidence: govern trip history as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

26 — Alarm History

Symptom Evidence: govern alarm history as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

27 — Leakage

Symptom Evidence: govern leakage as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

28 — Odour/Smoke Boundary

Symptom Evidence: govern odour/smoke boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

29 — Operator Observation

Symptom Evidence: govern operator observation as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

30 — Trend Confidence

Symptom Evidence: govern trend confidence as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

31 — Bearing Noise

Bearing Deterioration: govern bearing noise as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

32 — Bearing Vibration

Bearing Deterioration: govern bearing vibration as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

33 — Temperature

Bearing Deterioration: govern temperature as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

34 — Radial Play Boundary

Bearing Deterioration: govern radial play boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

35 — Axial/Endplay Boundary

Bearing Deterioration: govern axial/endplay boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

36 — Wear Debris

Bearing Deterioration: govern wear debris as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

37 — Race Damage Boundary

Bearing Deterioration: govern race damage boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

38 — Rolling-Element Damage Boundary

Bearing Deterioration: govern rolling-element damage boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

39 — Cage Damage Boundary

Bearing Deterioration: govern cage damage boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

40 — Lubrication Evidence

Bearing Deterioration: govern lubrication evidence as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

41 — Contamination Evidence

Bearing Deterioration: govern contamination evidence as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

42 — Misalignment Hypothesis

Bearing Deterioration: govern misalignment hypothesis as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

43 — Overload Boundary

Bearing Deterioration: govern overload boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

44 — Thermal Damage

Bearing Deterioration: govern thermal damage as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

46 — Shaft Seal Leakage

Seal Leakage: govern shaft seal leakage as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

47 — Internal Seal Boundary

Seal Leakage: govern internal seal boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

48 — Oil Leakage

Seal Leakage: govern oil leakage as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

49 — Air Leakage Boundary

Seal Leakage: govern air leakage boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

50 — Seal Wear

Seal Leakage: govern seal wear as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

51 — Seal Hardening Boundary

Seal Leakage: govern seal hardening boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

52 — Seal Damage

Seal Leakage: govern seal damage as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

53 — Shaft/Journal Condition

Seal Leakage: govern shaft/journal condition as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

54 — Pressure Influence

Seal Leakage: govern pressure influence as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

55 — Temperature Influence

Seal Leakage: govern temperature influence as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

56 — Lubricant Compatibility Boundary

Seal Leakage: govern lubricant compatibility boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

57 — Contamination

Seal Leakage: govern contamination as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

58 — Installation Damage Boundary

Seal Leakage: govern installation damage boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

59 — Leak Chronology

Seal Leakage: govern leak chronology as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

61 — Rub Evidence

Rotor / Element Contact: govern rub evidence as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

62 — Scoring

Rotor / Element Contact: govern scoring as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

63 — Metal Transfer Boundary

Rotor / Element Contact: govern metal transfer boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

64 — Rotor Surface Damage

Rotor / Element Contact: govern rotor surface damage as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

65 — Housing Contact Boundary

Rotor / Element Contact: govern housing contact boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

66 — Timing Loss Boundary

Rotor / Element Contact: govern timing loss boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

67 — Bearing Collapse Hypothesis

Rotor / Element Contact: govern bearing collapse hypothesis as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

68 — Clearance Loss

Rotor / Element Contact: govern clearance loss as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

69 — Thermal Growth Boundary

Rotor / Element Contact: govern thermal growth boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

70 — Foreign Object

Rotor / Element Contact: govern foreign object as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

71 — Severe Vibration

Rotor / Element Contact: govern severe vibration as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

72 — Metal Debris

Rotor / Element Contact: govern metal debris as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

73 — Seizure Risk

Rotor / Element Contact: govern seizure risk as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

74 — Stop/Escalate Decision

Rotor / Element Contact: govern stop/escalate decision as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

76 — Wrong Lubricant

Lubrication Failure: govern wrong lubricant as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

77 — Low Lubricant

Lubrication Failure: govern low lubricant as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

78 — Lubricant Starvation

Lubrication Failure: govern lubricant starvation as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

79 — Oil-Flow Restriction Boundary

Lubrication Failure: govern oil-flow restriction boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

80 — Degraded Lubricant

Lubrication Failure: govern degraded lubricant as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

81 — Oxidation Boundary

Lubrication Failure: govern oxidation boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

82 — Viscosity Boundary

Lubrication Failure: govern viscosity boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

83 — Water Contamination

Lubrication Failure: govern water contamination as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

84 — Particle Contamination

Lubrication Failure: govern particle contamination as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

85 — Mixed Fluid

Lubrication Failure: govern mixed fluid as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

86 — Foaming

Lubrication Failure: govern foaming as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

87 — High Temperature

Lubrication Failure: govern high temperature as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

88 — Filter Evidence

Lubrication Failure: govern filter evidence as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

89 — Oil-Analysis Evidence

Lubrication Failure: govern oil-analysis evidence as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

90 — Correlation

Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

91 — Dust/Particles

Contamination Failure: govern dust/particles as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

92 — Water

Contamination Failure: govern water as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

93 — Corrosion Debris

Contamination Failure: govern corrosion debris as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

94 — Wear Debris

Contamination Failure: govern wear debris as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

95 — Sealant/Debris Boundary

Contamination Failure: govern sealant/debris boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

96 — Foreign Material

Contamination Failure: govern foreign material as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

97 — Dirty Service Practice

Contamination Failure: govern dirty service practice as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

98 — Open-Port Contamination

Contamination Failure: govern open-port contamination as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

99 — Intake Failure

Contamination Failure: govern intake failure as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

100 — Filter Bypass

Contamination Failure: govern filter bypass as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

101 — Oil Contamination

Contamination Failure: govern oil contamination as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

102 — Post-Maintenance Contamination

Contamination Failure: govern post-maintenance contamination as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

103 — Particle Path

Contamination Failure: govern particle path as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

104 — Damage Pattern

Contamination Failure: govern damage pattern as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

105 — Evidence Preservation

Contamination Failure: govern evidence preservation as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

106 — High Discharge Temperature

Thermal Damage: govern high discharge temperature as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

107 — High Oil Temperature

Thermal Damage: govern high oil temperature as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

108 — Overheating History

Thermal Damage: govern overheating history as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

109 — Cooler Failure

Thermal Damage: govern cooler failure as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

110 — Ventilation/Recirculation

Thermal Damage: govern ventilation/recirculation as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

111 — Thermostatic/Bypass Boundary

Thermal Damage: govern thermostatic/bypass boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

112 — High Pressure/Load

Thermal Damage: govern high pressure/load as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

113 — Lubricant Degradation

Thermal Damage: govern lubricant degradation as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

114 — Bearing Heat

Thermal Damage: govern bearing heat as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

115 — Seal Heat

Thermal Damage: govern seal heat as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

116 — Rotor Clearance Effect Boundary

Thermal Damage: govern rotor clearance effect boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

117 — Thermal Discolouration

Thermal Damage: govern thermal discolouration as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

118 — Deposit Formation

Thermal Damage: govern deposit formation as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

119 — Sensor Plausibility

Thermal Damage: govern sensor plausibility as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

120 — Correlation

Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

121 — Water Contamination

Corrosion & Chemical Attack: govern water contamination as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

122 — Condensation Boundary

Corrosion & Chemical Attack: govern condensation boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

123 — Corrosion Evidence

Corrosion & Chemical Attack: govern corrosion evidence as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

124 — Pitting

Corrosion & Chemical Attack: govern pitting as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

125 — Surface Attack

Corrosion & Chemical Attack: govern surface attack as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

126 — Lubricant Chemistry Boundary

Corrosion & Chemical Attack: govern lubricant chemistry boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

127 — Process Vapour Boundary

Corrosion & Chemical Attack: govern process vapour boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

128 — Cleaning Chemical Boundary

Corrosion & Chemical Attack: govern cleaning chemical boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

129 — Storage Corrosion

Corrosion & Chemical Attack: govern storage corrosion as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

130 — Idle-Period Exposure

Corrosion & Chemical Attack: govern idle-period exposure as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

131 — Material Compatibility Boundary

Corrosion & Chemical Attack: govern material compatibility boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

132 — Bearing Corrosion

Corrosion & Chemical Attack: govern bearing corrosion as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

133 — Rotor Corrosion

Corrosion & Chemical Attack: govern rotor corrosion as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

134 — Housing Corrosion

Corrosion & Chemical Attack: govern housing corrosion as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

135 — Specialist Disposition

Corrosion & Chemical Attack: govern specialist disposition as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

137 — Filter Failure

Foreign-Object Damage: govern filter failure as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

138 — Loose Component

Foreign-Object Damage: govern loose component as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

139 — Service Debris

Foreign-Object Damage: govern service debris as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

140 — Fastener/Debris Boundary

Foreign-Object Damage: govern fastener/debris boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

141 — Particle Impact

Foreign-Object Damage: govern particle impact as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

142 — Rotor Damage

Foreign-Object Damage: govern rotor damage as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

143 — Housing Damage

Foreign-Object Damage: govern housing damage as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

144 — Valve/Path Damage Boundary

Foreign-Object Damage: govern valve/path damage boundary as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

145 — Debris Identity

Foreign-Object Damage: govern debris identity as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

146 — Entry Path

Foreign-Object Damage: govern entry path as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

147 — Secondary Debris

Foreign-Object Damage: govern secondary debris as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

148 — Evidence Bag/Tag

Foreign-Object Damage: govern evidence bag/tag as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

149 — System Inspection

Foreign-Object Damage: govern system inspection as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

150 — Rca Escalation

Foreign-Object Damage: govern RCA escalation as an evidence-supported failure-mode hypothesis. Record the observed symptom, chronology, operating state, trend/measurement, inspection evidence, plausible mechanism, competing causes, confidence and escalation decision. Do not convert sound, temperature, vibration or debris alone into an internal diagnosis. Use exact airend/model procedures for intrusive inspection and preserve evidence before cleaning or dismantling changes the condition.

151 — Premium Airend Failure-Mode Evidence Register

152 — Symptom-to-Mechanism Matrix

153 — Symptom Does Not Identify Failure Mode

Noise, heat or vibration must be correlated with operating and inspection evidence.

154 — Failure Mode Is Not Root Cause

Bearing deterioration describes a component failure mode; contamination, lubricant condition, misalignment, overheating or operation outside limits may explain why it developed.

156 — Internal Contact Is an Escalation Event

Rotor/element contact, abnormal metal debris or severe vibration can make continued operation unsafe and worsen damage.

157 — Intrusive Diagnosis Is Controlled Work

Opening an airend changes the evidence and introduces contamination/assembly risk.

158 — Technical / Failure-Mode Verification Gate

Verify identity, chronology, symptoms, trends, lubricant/debris evidence, competing mechanisms and inspection. No internal diagnosis from sound/temperature alone is permitted.

160 — AEO / Engineering FAQ Layer

Answer what airend failure modes exist, why symptoms are insufficient, what bearing failure can mean, why debris should be preserved, when operation should stop and how failure mode differs from root cause.