McDonnell Douglas DC-10-30 N39081

Summary

On 25 April 2000 at about 23:42 local time, a McDonnell Douglas DC-10-30 registered N39081, operated by Continental Airlines, Inc., was involved in an accident near Newark, New Jersey, United States. 234 people were on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

25 April 2000 at 23:42

Classification

Accident

Location

Newark, New Jersey, United States

Nearest airport

Newark International (EWR)

Coordinates

Not recorded

Aircraft

McDonnell Douglas DC-10-30

Registration

N39081

Category

Airplane

Engines

3

Operator

Continental Airlines, Inc.

Operating rule

Part 121: Air Carrier

Purpose of flight

Unknown

Phase of flight

Not recorded

Route

Unknown → Brussels

Aircraft damage

Substantial

Weather

VMC

Light

Dusk

NTSB number

NYC00FA122

Nobody was injured.

Stress rupture of the 2nd-stage low pressure turbine anti-rotation nozzle locks, resulting from inadequate nozzle lock design.

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

Read the full NTSB narrative

At V1, the DC-10-30's number 1 engine, a General Electric CF6-50C2, experienced a casing breach when the 2nd-stage low pressure turbine (LPT) anti-rotation nozzle locks failed. The breach occurred in the turbine plane, between approximately the 3 o'clock and 9 o'clock positions. Debris from the breach resulted in collateral damage to the numbers 2 and 3 engines, the fuselage, and the left landing gear. In May 1993, the engine manufacturer issued a service bulletin to replace existing nozzle locks with ones that had thicker posts and arms. The change required modification of the LPT case nozzle lock holes. In March 1994, the manufacturer issued another service bulletin, SB 72-1082, which introduced a newly designed nozzle lock. The new locks, which were installed on the accident engine, utilized original diameter stud shanks, but were manufactured from a different material, and did not require modification of the LPT case. There were two previously reported failures of SB 72-1082 LPT nozzle locks, discovered during routine under-cowl inspections. In one case, all of the 2nd-stage nozzle locks were broken. The nozzle segments had rotated 120 degrees within the LPT case, but the case itself was not breached. In the second case, two 4th-stage nozzle locks had failed, but there was no collateral damage. According to the engine manufacturer, the failures were intergranular, "suggesting either stress rupture or sustained peak low cycle fatigue." Safety Board examination, of the only two recovered 2nd-stage nozzle locks from the accident engine, along with a section of casing with a nozzle lock stud attached, revealed intergranular fracture features, degradation at the surface of the fracture features, and grain boundaries, typical of oxidation damage. The intergranular fractures and oxidation damage found at the grain boundaries were consistent with stress rupture. An examination of a cracked 2nd stage nozzle lock, from a comparison engine, also revealed oxidation and intergranular fracture features, consistent with stress rupture.

Quoted verbatim from the NTSB record.