List of maintenance-related failures
Incident
On March 20, 2001 a Lufthansa Airbus A320 almost crashed shortly after takeoff because of reversed wiring in the captain's sidestick flight control. Quick action by the co-pilot, whose sidestick was not faulty, prevented a crash
Cause
The investigation has focused on maintenance on the captain's controls carried out by Lufthansa Technik just before the flight. During the previous flight, a problem with one of the two elevator/aileron computers (ELAC) had occurred. An electrical pin in the connector was found to be damaged and was replaced. It has been confirmed that two pairs of pins inside the connector had accidentally been crossed during the repair. This changed the polarity in the sidestick and the respective control channels “bypassing” the control unit, which might have sensed the error and would have triggered a warning. Clues might have been seen on the electronic centralized aircraft monitor (ECAM) screen during the flight control checks, but often pilots only check for a deflection indication, not the direction. Before the aircraft left the hangar, a flight control check was performed by the mechanic, but only using the first officer’s sidestick.
Lock pin
Figure 14-30. A description of a Lufthansa Airbus A320 that almost crashed due to reversed wiring of the flight controls.
Accident Alaska Airlines Flight 261, a McDonnell Douglas MD-83 aircraft, experienced a fatal accident on January 31, 2000, in the Pacific Ocean. The two pilots, three cabin crewmembers, and 83 passengers on board were killed and the aircraft was destroyed.
Cause
The subsequent investigation by the National Transportation Safety Board (NTSB) determined that inadequate maintenance led to excessive wear and catastrophic failure of a critical flight control system during flight. The probable cause was stated to be “a loss of airplane pitch control resulting from the in-flight failure of the horizontal stabilizer trim system jackscrew assembly’s acme nut threads. The thread failure was caused by excessive wear resulting from Alaska Airlines insufficient lubrication of the jackscrew assembly.”
Incident August 26, 1993, an Excalibur Airways Airbus 320 took off from London-Gatwick Airport (LGW) and exhibited an undemanded roll to the right on takeoff, a condition which persisted until the aircraft landed back at LGW 37 minutes later. Control of the aircraft required significant left sidestick at all times and the flight control system was degraded by the loss of spoiler control.
Cause Technicians familiar with Boeing 757 flap change procedures lacked the knowledge required to correctly lock out the spoilers on the Airbus during the flap change work that was done the day before the flight. Turnover to technicians on the next shift compounded the problem. No mention of incorrect spoiler lockout procedure was given since it was assumed that the 320 was like the 757. The flap change was operationally checked, but the spoiler remained locked out incorrectly and was not detected by the flight crew during standard functional checks. The lack of knowledge on Airbus procedures was considered a primary cause of this incident.
Incident
April 26, 2001, an Emery Worldwide Airlines DC-8-71F left main landing gear would not extend for landing.
Cause
Probable cause was failure of maintenance to install the correct hydraulic landing gear extension component and the failure of inspection to comply with post-maintenance test procedures. No injuries.
Accident
On May 25, 2002, China Airlines Flight 611 Boeing 747 broke into pieces in mid-air and crashed, killing all 225 people on board.
Cause
The accident was the result of metal fatigue caused by inadequate maintenance after a previous incident.
Accident
On August 26, 2003, a Colgan Air Beech 1900D crashed just after takeoff from Hyannis, Massachusetts. Both pilots were killed.
Cause
The improper replacement of the forward elevator trim cable and subsequent inadequate functional check of the maintenance performed that resulted in a reversal of the elevator trim system and a loss of control in flight. Factors were the flight crew’s failure to follow the checklist procedures and the aircraft manufacturer’s erroneous depiction of the elevator trim drum in the maintenance manual.
Accident
On September 28, 2007, American Airlines Flight 1400 DC-9 experienced an in-flight engine fire during departure climb from Lambert St. Louis International Airport (STL). During the return to STL, the nose landing gear failed to extend, and the flight crew executed a go-around, during which the crew extended the nose gear using the emergency procedure. The flight crew conducted an emergency landing, and the 2 flight crewmembers, 3 flight attendants, and 138 passengers deplaned on the runway. No occupant injuries were reported, but the airplane sustained substantial damage from the fire.
Cause
American Airlines' maintenance personnel's use of an inappropriate manual engine-start procedure, which led to the uncommanded opening of the left engine air turbine starter valve, and a subsequent left engine fire.
