31421004
COWLING
Specifications
- Part Number
- 31421004
- Manufacturer
- ROHR
- ATA ChapterMaintenance system chapter
- 54 — Nacelles / Pylons
- CapabilitySystem area (hydraulics, avionics, landing gear…)
- Structures
- Inventory ClassRotable, expendable, or consumable
- Expendable
- Certification
- OEM
- Aircraft Category
- Unknown
- Criticality
- Standard
Service Reliabilityfrom FAA SDR (Service Difficulty Reports)
- SDR reports
- 1
- Replace events
- 1
- Repair events
- 0
- K-code events
- 1
Directional indicator only. Reflects what operators reported to the FAA when a difficulty was logged — not a fleet-normalized failure rate or a cost-based BER. Use alongside operator-specific data.
Airworthiness Directive coverage
FAA / EASA public regulatory data
- FAAAD 2025-04-01effective Apr 8, 2025Mixed actions
The FAA is adopting a new airworthiness directive (AD) for all The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. This AD was prompted by two engine fan blade-out (FBO) events that resulted in the separation of engine inlet cowl and fan cowl parts from the airplane. In one event, fan cowl parts damaged the fuselage, which caused loss of pressurization and subsequent emergency descent. This AD requires replacing specified inlet cowl aft bulkhead fasteners for certain airplanes; for certain other airplanes, inspecting the inlet cowl aft bulkhead fastener and replacing the fasteners if rivets are found, and, for all airplanes, replacement of the crushable spacers used in the attachment of the inlet cowl to the engine fan case; or as an option, installing a serviceable inlet cowl. This AD also requires revising the existing maintenance or inspection program, as applicable, to incorporate new airworthiness limitations (AWLs). The FAA is issuing this AD to address the unsafe condition on these products.
Directives citing this part number in the FAA / EASA regulatory corpus we have processed — not a complete historical AD list. An AD is a compliance requirement that drives scheduled work (inspections, replacements, modifications) on the fleets that carry the part; a directive naming this PN as the replacement part is install demand, not an action against it — and none of this is a prediction that the part will fail.
Airframe Applicability(1)
Data Sources(1)
- 2026-03-07
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