On September 9, 1999, a Douglas DC-9 (registration N993Z) operated by Trans World Airlines - TWA was involved in an aviation accident near Nashville, United States of America during landing or approach. No fatalities were reported. Investigators recorded the probable cause as: A preexisting crack on the left main landing gear outer cylinder housing and the first officer's failure to maintain the proper rate of descent resulting in a hard landing on touchdown, and subsequent total failure and separation of the left main landing gear… This summary draws on records from the Bureau of Aircraft Accidents Archives (B3A); 1 related events involving the same aircraft type or operator are linked below.
A hard landing caused by the first officer's failure to maintain proper sink rate led to separation of the left main landing gear during rollout. The pilot-in-command did not take corrective action despite recognizing the problem. A preexisting crack was found in the landing gear.
Incident Summary
During the landing, the first officer failed to maintain the proper rate of descent, resulting in a hard landing on touchdown. Subsequently, during the landing rollout, the left main landing gear separated from the aircraft. The pilot-in-command stated that he knew the first officer was not going to make a good landing but did not take any corrective action beyond initially instructing the first officer to increase power.
Findings
Examination of the left main landing gear assembly revealed a preexisting crack in the outer cylinder housing. The hard landing and the preexisting crack contributed to the total failure and separation of the landing gear.
Probable Cause
The official probable cause is a preexisting crack on the left main landing gear outer cylinder housing and the first officer's failure to maintain the proper rate of descent, resulting in a hard landing on touchdown and subsequent total failure and separation of the left main landing gear on landing rollout. A contributing factor was the pilot-in-command's improper supervision of the first officer during the approach phase of the landing.