52B521
OEM2 Active ADsEngine — referenced in AD 2018-21-11
Where to Buy
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Documentation
General information based on part classification, not a certification determination. Your operator's quality manual governs.
Life-Limited Part — Confirm Retirement Limits Before Purchase
ATA 72 components may be subject to mandatory retirement limits. Consult the aircraft maintenance manual to confirm life limits. An unbroken chain of 8130-3 tags and/or maintenance records from new is required for airworthy installation.
What to ask the seller for
- FAA Form 8130-3 from the PAH or an authorized release traceable to the PAH
- Manufacturer's CofC if a Form 8130-3 was not issued
Governing reference: FAA Order 8130.21J
PMA Alternatives
No PMA alternatives found for this part. This does not mean none exist — only that none are currently in our database.
Supplemental Type Certificates
FAA-approved modifications that reference this part number
No current STCs reference this part number in their description.
Airworthiness Directives2 FAA Active20 EASA
Synced 40 days ago (09/27/2026)AD 2018-21-11
Airworthiness Directives; Pratt & Whitney Division Engines
The FAA is superseding Airworthiness Directive (AD) 2018-21- 11, which applied to all Pratt & Whitney Division (PW) Model PW4074D, PW4077D, PW4084D, PW4090, and PW4090-3 engines with a low-pressure compressor (LPC) fan hub, part number (P/N) 51B821 or P/N 52B521, installed. AD 2018-21-11 required performing repetitive eddy current inspections (ECIs) and fluorescent penetrant inspections (FPIs) for cracks in certain LPC fan hubs and removing LPC fan hubs from service that fail any inspection. Since the FAA issued AD 2018-21-11, the FAA determined that affected LPC fan hub assemblies can meet the published certificated life limit without the need for the required repetitive FPI inspections in AD 2018-21-11, and the repetitive ECI inspections require shortened intervals. Based on a report of another incident, the FAA determined that the unsafe condition is likely to exist or develop on additional LPC fan hub assemblies and PW model engines. This AD expands the applicability to include Model PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 engines with any part number LPC fan hub assembly installed and requires performing repetitive ECIs of the LPC fan hub assembly and, depending on the results of the inspections, removing the LPC fan hub assembly from service. The FAA is issuing this AD to address the unsafe condition on these products.
FR-2018-23712
Airworthiness Directives; Pratt & Whitney Division (PW) Turbofan Engines
We are adopting a new airworthiness directive (AD) for all Pratt & Whitney Division (PW) PW4074D, PW4077D, PW4084D, PW4090, and PW4090-3 turbofan engines with a low-pressure compressor (LPC) fan hub, part number (P/N) 51B821 or P/N 52B521, installed. This AD was prompted by updated low-cycle fatigue analysis techniques that indicate certain LPC fan hubs could crack before their published life limit. This AD requires repetitive eddy current inspections (ECIs) and fluorescent penetrant inspections (FPIs) for cracks in certain LPC fan hubs and removal of LPC fan hubs from service that fail inspection. We are issuing this AD to address the unsafe condition on these products.
EASAEASA Airworthiness Directives— applicable to this aircraft type
Turbine - High-Pressure Compressor Drum Rotor Disk - Inspection / Replacement
Turbine - High-Pressure Compressor 7th-Stage Integrally Bladed Rotor - Inspection / Replacement
Engine - Combustion Section Outer Diffuser Case - Inspection / Removal
Engine - 1st-Stage Low-Pressure Compressor Blades - Inspection / Removal
Engine - High-Pressure Turbine 1st Stage Hub - Inspection / Replacement
[Correction] Engine - Second Stage High Pressure Turbine Air Seals - Inspection / Removal
Engines - High-Pressure Compressor (HPC) Drum Rotor Disk Assembly - Inspection / Replacement
Engine - Front Turbine Hub Anti-Rotation Slots - Inspection / Replacement
Service Difficulty Reports
No Service Difficulty Reports
No failure reports found for this part number in the FAA SDR database.
Suspect-Parts Alerts (SUP/UPN)
No Suspect-Parts Alerts
This manufacturer is not named in any active FAA Suspect Unapproved Parts (SUP/UPN) notification.
NSN Cross-References
National Stock Numbers assigned to this part number by the U.S. Defense Logistics Agency
No government NSN assignment found for this part number in DLA WebFLIS PUBLOG.
Government Award Prices
U.S. government contract award prices from FPDS — unit prices for NSN purchases by DoD/DLA agencies
No government contract award price data found for this part number.
Identifiers
Manufacturer
Pratt & Whitney Division
Source
FAA Federal Register
ATA Chapter
72
Type
OEM