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Safety Recommendation Details

Safety Recommendation A-00-123
Details
Synopsis: ON 9/22/00, A US AIRWAYS BOEING 767-2B7(ER) AIRPLANE, N654US, EQUIPPED WITH GE CF6-80C2B2 ENGINES, EXPERIENCED AN UNCONTAINED FAILURE OF THE HPT STAGE 1 DISK IN THE NO. 1 ENGINE DURING A HIGH-POWER GROUND RUN FOR MAINTENANCE AT PHILADELPHIA INT'L. AIRPORT, PHILADELPHIA, PA. BECAUSE OF A REPORT OF AN IN-FLIGHT LOSS OF OIL, US AIRWAYS MECHANICS HAD REPLACED A SEAL ON THE NO. 1 ENGINE'S INTEGRAL DRIVE GENERATOR AND WERE PERFORMING THE HIGH-POWER ENGINE RUN TO CHECK FOR ANY OIL LEAKAGE. FOR THE MAINTENANCE CHECK, THE MECHANICS HAD TAXIED THE AIRPLANE TO A REMOTE TAXIWAY ON THE AIRPORT AND HAD PERFORMED THREE RUNUPS FOR WHICH NO ANOMALIES WERE NOTED. DURING THE FOURTH EXCURSION TO HIGH POWER, AT AROUND 93 PERCENT N1 RPM, THERE WAS A LOUD EXPLOSION FOLLOWED BY A FIRE UNDER THE LEFT WING OF THE AIRPLANE. THE MECHANICS SHUT DOWN THE ENGINES, DISCHARGED BOTH FIRE BOTTLES INTO THE NO. 1 ENGINE NACELLE, AND EVACUATED THE AIRPLANE. ALTHOUGH BOTH FIRE BOTTLES WERE DISCHARGED, THE FIRE CONTINUED UNTIL IT WAS EXTINGUISHED BY AIRPORT FIRE DEPARTMENT PERSONNEL. THE NO. 1 ENGINE AND THE AIRPLANE SUSTAINED SUBSTANTIAL DAMAGE. THE THREE MECHANICS WERE NOT INJURED.
Recommendation: TO THE FEDERAL AVIATION ADMINISTRATION: Require implementation of the eddy current inspection procedure being developed by General Electric for CF6-80C2 HPT stage 1 disk blade slot bottoms.
Original recommendation transmittal letter: PDF
Overall Status: Closed - Acceptable Action
Mode: Aviation
Location: Philadelphia, PA, United States
Is Reiterated: No
Is Hazmat: No
Is NPRM: No
Accident #: DCA00IA09
Accident Reports:
Report #: None
Accident Date: 9/23/2000
Issue Date: 12/12/2000
Date Closed: 3/25/2002
Addressee(s) and Addressee Status: FAA (Closed - Acceptable Action)
Keyword(s): Engine, Maintenance, Procedures, Procedures: Maintenance

Safety Recommendation History
From: NTSB
To: FAA
Date: 3/13/2003
Response: Notation 7290B: The National Transportation Safety Board has reviewed the Federal Aviation Administration’s (FAA) Final Rule; Request for Comments, “Airworthiness Directives; General Electric CF6-80A Series Turbofan Engines,” which was published in 68 Federal Register 1519 on January 13, 2003. The final rule requires initial and recurrent eddy current inspections of certain General Electric (GE) CF6 80A stage 1 high pressure turbine (HPT) rotor disks. The AD is intended to detect cracks that can cause separation of the HPT stage 1 disk and result in an uncontained engine failure. This final rule was issued as a result of a December 8, 2002, incident involving a Boeing 767 airplane, which experienced a stage 1 HPT rotor disk separation in the No. 1 engine resulting in an uncontained engine failure. The Safety Board supports the final rule in part and notes that it only requires an initial inspection be performed at the next engine shop visit (ESV) and recurrent inspections at each subsequent piece-part exposure. Unlike AD 2001-10-7, which was issued to address stage 1 HPT failures in GE CF6-80C2 engines, the subject final rule does not impose cyclic limits for the inspections of stage 1 HPT disks in CF6-80A engines. Issued in response to Safety Recommendation A-00-123, AD 2001-10-7 required disks with fewer than 1,500 cycles since new (CSN) on the effective date of the AD to be inspected at the next ESV but not to exceed 5,000 CSN; disks with more than 1,500 CSN on the effective date of the AD were required to be inspected at the next ESV but not to exceed 3,500 cycles in service since the effective date of the AD. Because the design and application of CF6-80A engines are similar to CF6-80C2 engines, the Safety Board believes that the subject final rule should impose similar cyclic limits on CF6 80A stage 1 HPT disk inspections. It is also noted that the FAA considers this final rule to be an interim action as it continues to investigate the cracking of stage 1 HPT rotor disks; the Board looks forward to long-term action by the FAA to address this issue. Thank you for the opportunity to comment on this final rule.

From: NTSB
To: FAA
Date: 3/25/2002
Response: With the issuance of the AD, the FAA has completed the action recommended. Accordingly, Safety Recommendation A-00-123 is classified "Closed--Acceptable Action."

From: FAA
To: NTSB
Date: 10/4/2001
Response: Letter Mail Controlled 10/11/2001 9:19:22 AM MC# 2010834: The FAA and GE established a focused inspection program for the CF6-80C2 HPT Stage 1 disk dovetail slot bottom. The inspection includes etch, fluorescent-penetrant inspection, and eddy current inspection. GE developed the eddy current inspection Data Source: NTSB Recommendations to FAA and FAA Responses procedure for the HPT Stage 1 disk dovetail slot bottom, trained the CF6-80C2 overhaul shops, deployed the inspection kits, and issued ASB 72-A1026 in January 2001. On May 18, 2001, the FAA issued AD 2001-10-07 to mandate the inspection procedures contained in ASB CF6-80C2 72-A1026. I have enclosed a copy of the AD for the Board's information. I consider the FAA's action to be completed in response to this safety recommendation.

From: NTSB
To: FAA
Date: 6/20/2001
Response: Pending adoption of a final rule to require eddy current inspection of GE CF6-80C2 HPT Stage 1 disk dovetail slot bottoms, Safety Recommendation A-00-123 is classified "Open-Acceptable Response."

From: FAA
To: NTSB
Date: 3/2/2001
Response: Letter Mail Controlled 03/07/2001 11:26:17 AM MC# 2010198 The FAA agrees with this recommendation. The FAA and GE have established a focused inspection program for the CF6-80C2 HPT Stage 1 disk dovetail slot bottom. The inspection includes etch, fluorescent-penetrant inspection, and eddy current inspection. GE has developed the eddy current inspection procedure for the HPT Stage 1 disk dovetail slot bottom, trained the CF6-80C2 overhaul shops, deployed the inspection kits, and issued ASB 72-A1026 in January 2001. The FAA plans to mandate this inspection as outlined in response to Safety Recommendation A-00-121.