BOEING 757-251 near Atlanta, GA — 2011-10-10

Probable cause

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.

NTSB narrative

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.

Analysis

Primary failure mode

Mechanical failure

First missed decision gate

Inspection of engine components should have been more thorough before the flight.

NTSB coding

• Uncontained engine failure · Takeoff-rejected takeoff

Evidence available

• FDR / data
• Photos
• 10 docket documents

Docket documents10

• Flight Data Recorder 10 - Attachment 1 (FDR tabular data for event)fdr
• Flight Data Recorder 10 - Attachment 2 (FDR tabular data for first previous flight)fdr
• Flight Data Recorder 10 - Attachment 3 (FDR tabular data for second previous flight)fdr
• Flight Data Recorder 10 - Specialist's Factual Reportfdr
• Materials Laboratory 15 - Attachment 1 - SEM Image of Fracture Surfacephotos
• Materials Laboratory 15 - Factual Report 12-028 (with 63 embedded images)photos
• Materials Laboratory 15 - Factual Report 12-028 - Appendices A - D (with 69 embedded images)photos
• Materials Laboratory 15 - Factual Report 12-028 - Appendices E - G (with 50 embedded images)photos
• Materials Laboratory 15 - Study Report 12-028S (with 2 embedded images)photos
• Powerplants 8 - Factual Report of Group Chairman with 21 embedded photographsphotos

Related mishaps

• CESSNA 501

  2020-12-31 · Opa Locka, FL

• BOEING 767

  2016-10-28 · Chicago, IL

• BOEING COMPANY BOEING 777-236

  2015-09-08 · Las Vegas, NV