Boeing 757-223 N609AA

Summary

On 24 August 2003 at about 15:10 local time, a Boeing 757-223 registered N609AA was involved in an incident near Miami, Florida, United States. 169 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

24 August 2003 at 15:10

Classification

Incident

Location

Miami, Florida, United States

Nearest airport

Miami International (MIA)

Coordinates

25.7931, -80.2906

Aircraft

Boeing 757-223

Registration

N609AA

Category

Airplane

Engines

2

Operator

Not recorded

Operating rule

Part 121: Air Carrier

Phase of flight

Not recorded

Route

Miami → Chicago

Aircraft damage

Minor

Weather

VMC

Light

Day

NTSB number

MIA03IA168

Nobody was injured.

The failure of maintenance personnel from the aircraft operator to identify a missing left main landing gear truck beam shield and damage to the left main landing gear truck beam which resulted in the fracture of the truck beam as a result of stress corrosion cracking.

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

Read the full NTSB narrative

The first officer stated that during preflight examination of the airplane he didn't see anything wrong with the aircraft and it was deemed suitable for flight. During taxi, the airplane suddenly dipped left and skidded to a stop. The flightcrew assessed a possible tire blowout and after contacting ground control the aircraft behind them confirmed it was the left outboard main tire and that it was smoking. Airport emergency authorities responded and noted the left main landing gear had failed. The authorities observed no smoke or fire. Maintenance personnel confirmed that the bogie on the left main gear had failed. The left main landing gear truck beam had fractured in two pieces between the aft axle and the truck pivot pin. There was no truck beam shield present with the wreckage although the attach straps were present. The fracture occurred about 14 inches forward of the aft axle centerline. Metallurgical analysis revealed the fracture of the truck beam was the result of stress corrosion cracking (SCC). The SCC was precipitated by damage to the protective finishes on the lower surface of the beam. The material of the beam is very susceptible to SCC at the high strengths specified. It is vitally important to maintain the protective finishes and prevent exposure of the base material to atmospheric conditions when loaded. According to operator, the landing gear was delivered new with the airplane on July 29, 1996 and had accumulated 7,517 cycles since new. There was no truck beam shield present with the wreckage although the attach straps were present. The Boeing 757 configuration deviation list (CDL), which was current at the time of the incident, lists items that can be missing for flight. The main landing gear truck beam shields may be missing for flight. There was no requirement to inspect the landing gear for damage prior to dispatch with a truck beam shield missing. Maintenance personnel had not identified the missing truck beam shield on the left main landing gear of the airplane and the shield was not on the current list of missing items under the CDL.

Quoted verbatim from the NTSB record.