Boeing DC-9-82 N450AA

Summary

On 25 June 1999 at about 21:40 local time, a Boeing DC-9-82 registered N450AA, operated by Wilmington Trust C0, was involved in an incident near San Diego, California, United States. 141 people were on board and nobody was injured. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

25 June 1999 at 21:40

Classification

Incident

Location

San Diego, California, United States

Nearest airport

Lindberg Field (SAN)

Coordinates

32.9308, -117.0102

Aircraft

Boeing DC-9-82

Registration

N450AA

Category

Airplane

Engines

2

Operator

Wilmington Trust C0

Operating rule

Part 121: Air Carrier

Purpose of flight

Unknown

Phase of flight

Not recorded

Route

San Diego → Dallas

Aircraft damage

Not recorded

Weather

VMC

Light

Day

NTSB number

LAX99IA230

Nobody was injured.

failure of the number three bearing. The resulting oil leak from the bearing led to coke/carbon buildup, which resulted in chafing of the turbine's low-pressure compressor drive shaft on the rear compressor seal tube and subsequent fracture of the drive shaft.

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

Read the full NTSB narrative

The crew heard a pop after the nose wheel lifted up during rotation on takeoff and a loss of power occurred on the right engine. An emergency was declared and an uneventful landing was completed. All of the third and fourth stage turbine blades fractured at the root and no fatigue marks were noted. The second stage turbine blades fractured at 1/2 to 2/3 span. All low-pressure turbine nozzle guide vanes exhibited significant leading edge rub and had meshed with adjacent turbine blade trailing edges. The low-pressure compressor drive turbine shaft fractured approximately 25 inches aft of the low-pressure compressor. This fracture was twisted and contained a large area of displaced and galled metal; coke/carbon was observed under the galled metal. The number 3 bearing was damaged; all balls were worn with flat spots up to 1/2 the ball circumference. Spalling was evident on the inner and outer race, but no race spinning was noted. The cage was intact, but worn. No evidence of oil starvation or overheating was evident. A flow check of the oil supply system to the number 3 bearing was completed with no blockage or flow anomalies detected. An inspection by an independent laboratory could not determine a cause for the bearing failure. The number 3 bearing had accumulated 12,487 hours since new.

Quoted verbatim from the NTSB record.