Delta Air Lines Flight 1080

Delta Air Lines Flight 1080

Lockheed L-1011-1 Tristar reg. N729DA similar to the accident airplane
Incident
Date	April 12, 1977
Summary	Loss of pitch control due to jammed elevator
Site	Los Angeles International Airport
Aircraft type	Lockheed L-1011
Operator	Delta Air Lines
Registration	N707DA
Flight origin	San Diego International Airport, San Diego, United States
Destination	Los Angeles International Airport, Los Angeles, United States
Passengers	41 [1][2]
Crew	11
Fatalities	0
Injuries	0
Survivors	52

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, the Lockheed L-1011's left elevator became stuck in a fully upwards position, leading to the aircraft pitching up aggressively and causing the plane 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 airplane and allowed the pilots to land the airplane. ^[1][3]

An investigation found that the pressurization and depressurization of the airplane during flight cycles caused water to be pushed inside a bearing, heavily corroding it and causing the malfunction. The FAA issued an emergency airworthiness directive instructing airlines to do a check of the bearing. Following a similar incident two months later, the FAA made mandatory for crews to inspect the elevators before each takeoff.^[1]

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.^[1]

For his skill in landing the crippled airplane, the captain, Jack McMahan, was awarded the FAA's Distinguished Service Award.^[2]

References