The diffuser case of a Pratt & Whitney PW2037(M) engine installed on a B757-200 airplane ruptured during takeoff roll at Hartsfield-Jackson Atlanta International Airport, Atlanta, Georgia (ATL). The force of the case rupture caused the hinge-mounted core cowl halves to distort and strike the leading edge and underside of the airplane's left wing, resulting in minor airplane damage. Metallurgical investigation and review of the engine's maintenance records determined that cracks in the engine's diffuser case rear flange (M-flange) and cracks in the HPT case forward flange (M-flange) were not detected when the cases underwent fluorescent penetrant inspection (FPI) during the engine's last shop visit, 3,479 cycles before the event. The undetected cracks continued to propagate, leading to the in-service diffuser case rupture. The reason for the ineffective inspection was not determined, but was narrowed to chronological- and operator-based scenarios. A suspect population of 50 engines was identified that included sub-populations for both possibilities. The FAA published airworthiness directive (AD) 2014-05-32, requiring the M-flanges of PW2037, PW2037D, PW2037M, PW2040, PW2040D, PW2043, PW2143, PW2240, PW2337, PW2643, and F117-PW-100 engines in the identified suspect population to undergo eddy current inspection within 100 flight cycles or 30 days. No additional cracks were found. As a result of the investigation, the FAA published airworthiness directive (AD) 2014-05-32, which requires the M-flanges of PW2000 engines with certain diffuser and HPT cases installed to undergo eddy current inspection within 100 flight cycles or 30 days. AD 2014-05-32 also requires that high-sensitivity FPI penetrant be used when accomplishing FPI of the PW2037, PW2037D, PW2037M, PW2040, PW2040D, PW2043, PW2143, PW2240, PW2337, PW2643, and F117-PW-100 diffuser case M-flange and the HPT case M-flange. In addition, AD 2014-05-32 makes the performance of diffuser and HPT case M-flange high-sensitivity FPI at every piece part opportunity an airworthiness limitation for PW2037, PW2037D, PW2037M, PW2040, PW2040D, PW2043, PW2146, PW2240, PW2337, PW2643, and F117-PW-100 engines.
the return to service of overhauled airplane engine parts with undetected fatigue cracks, resulting in complete loss of engine power and uncontained engine failure. A contributing factor was the inadequate diffuser and HPT case inspection procedure.
— 213,644 samples, 25 parameters, 21:48:20.0 to 23:08:20.9.
| Parameter | Max | at | Min | at | Final | at |
|---|---|---|---|---|---|---|
| Pressure altitude ft | 40,012.0 | 22:13:06.1 | 141.0 | 21:50:35.1 | 847.0 | 23:08:20.1 |
| Computed airspeed kts | 384.0 | 21:48:23.4 | 0.0 | 21:48:20.4 | 384.0 | 23:08:20.4 |
| Vertical acceleration g | 1.3 | 21:53:42.4 | 0.8 | 23:03:03.8 | 1.0 | 23:08:20.9 |
| Engine 1 N1 %RPM | 91.9 | 22:00:36.0 | 21.2 | 23:04:25.0 | 22.1 | 23:08:20.0 |
| Engine 2 N1 %RPM | 92.4 | 22:00:45.5 | 21.6 | 23:04:26.5 | 21.9 | 23:08:20.5 |
| Time | Event | Page |
|---|---|---|
| 15:15:45 EDT (approx.) | FDR first powered on and started recording data before the event | 3 |
| ~15:19:XX EDT (during takeoff roll, about 9 seconds of acceleration) | Aircraft accelerated for approximately 9 seconds, computed airspeed reached a maximum of 60 knots | 3 |
| ~60 kias | Flight crew heard a loud bang and noted left engine fire indications; No. 1 (left) engine failure during takeoff roll | 1 |
| Following the bang/fire indication | Captain aborted the takeoff; aircraft decelerated for approximately 23 seconds | 3 |
| After rejected takeoff | The airplane was taxied back to the gate without further incident and the passengers were deplaned normally | 1 |
Docket: data.ntsb.gov/Docket/?NTSBNumber=ENG12IA001. This brief is an analytical aid assembled from public records; it is not an investigative finding.