Delta Air Lines Flight 1080
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Lockheed L-1011-1 Tristar N729DA similar to the incident aircraft
|Date||April 12, 1977|
|Summary||Loss of pitch control due to malfunctioning elevator|
|Site||Los Angeles International Airport|
|Aircraft type||Lockheed L-1011|
|Operator||Delta Air Lines|
|Flight origin||San Diego International Airport, San Diego, United States|
|Destination||Los Angeles International Airport, Los Angeles, United States|
Delta Air Lines Flight 1080 was a scheduled flight notable for the incident that occurred on April 12, 1977 during the San Diego to Los Angeles leg of the flight. During the takeoff, it became apparent that the Lockheed L-1011's left elevator had become stuck in a fully upwards position, leading to the aircraft pitching up aggressively and causing the aircraft to lose speed and nearly stall. The pitching force, unable to be overcome by fully pushing the control column down, was counteracted by reducing the thrust on the L-1011's wing engines but not the tail engine. The differential thrust pitched down the nose of the airliner and allowed the pilots to land the aircraft. 
An investigation found that the pressurization and depressurization of the L-1011 during flight cycles caused water to be pushed inside a bearing, heavily corroding it and causing it to become jammed during a routine control surfaces check prior to takeoff. The FAA issued an emergency airworthiness directive instructing airlines to do a check of the bearing. However, this verification was not sufficient to prevent takeoff with a jammed elevator, and following a similar incident two months later, the FAA made it mandatory for crews to inspect the elevators before each takeoff.
As a result of the incidents, Lockheed redesigned the elevator systems to be redundant upon failure of the bearings, as well as adding a seal to the bearing and a deflector to reduce the amount of water contacting the part. Lockheed would also modify the pilot's manual to improve the Pitch Axis Control Assist Procedures. The FAA further made mandatory for pilots to be informed of this addition. 
For his skill in landing the crippled airplane, the captain, Jack McMahan, was awarded the FAA's Distinguished Service Award. The airplane was repaired and continued to fly for Delta until 1985. It was subsequently sold to American Trans Air, where it was registered with the tail number "N187AT". The airplane was scrapped in 2002. 
- "The Saving Of Flight 1080". Washington Post. 1978-10-08. ISSN 0190-8286. Retrieved 2018-05-19.
- "Flight 1080" (PDF). Tristar500.net. Retrieved 27 August 2018.
- "NASA Technical Paper : Development and Flight Evaluation of an Emergency Digital Flight Control System Using Only Engine Thrust on an F-15 Airplane" (PDF). Nasa.gov. Retrieved 27 August 2018.
- "Airworthiness directives: Lockheed-California Company Model, L-1011-385 Series Airplanes" (PDF). Federal Register. 42 (176): 45631–45632. 1977-09-12.
- "American Trans Air N187AT (Lockheed L-1011 TriStar - MSN 1077) (Ex N707DA ) | Airfleets aviation". www.airfleets.net. Retrieved 2020-02-08.
- portrait of N707DA the accident aircraft taking off
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