Boeing 757-251 N553NW

Summary

On 10 October 2011 at about 19:03 local time, a Boeing 757-251 registered N553NW, operated by Delta Air Lines Inc, was involved in an incident near Atlanta, Georgia, United States. 182 people were on board and nobody was injured. The aircraft was slightly damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

10 October 2011 at 19:03

Classification

Incident

Location

Atlanta, Georgia, United States

Nearest airport

Hartsfield - Jackson Atlanta I (ATL)

Coordinates

33.7633, -84.4017

Aircraft

Boeing 757-251

Registration

N553NW

Category

Airplane

Engines

2

Operator

Delta Air Lines Inc

Operating rule

Part 121: Air Carrier

Phase of flight

Not recorded

Route

Atlanta → Dallas

Aircraft damage

Minor

Weather

VMC

Light

Day

NTSB number

ENG12IA001

Nobody was injured.

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.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full 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. 

Quoted verbatim from the NTSB record.