Eastern Air Lines Flight 494
# Eastern Air Lines Flight 494

On April 21, 1985, Eastern Air Lines Flight 494 was a domestic flight from Hartsfield-Jackson Atlanta International Airport (ATL) to Piedmont Triad International Airport (GSO) using a McDonnell-Douglas DC-9. Shortly after takeoff, the flight experienced an uncommanded deployment of reverse thrust on the #2 engine. Flight 494 is one of the few recorded instances of an aircraft recovering safely from unintentional deployment of reverse thrust on one engine during flight.

## Flight

Shortly after takeoff from Hartsfield-Jackson Atlanta International Airport, Eastern Air Lines Flight 494 experienced an unintended deployment of reverse thrust of the #2 engine. This caused the aircraft to quickly roll to the right. Captain James Robertson and first officer J.L. Bellmer disabled the #2 engine, and regained control of the plane while still in a turn, just a few knots before stalling. The crew was then able to return to Atlanta by conducting a standard single-engine landing. At the time, there was no training offered to flight crews for identifying or recovering from an unintentional deployment of reverse thrust.

## Aircraft

The aircraft involved was a McDonnell Douglas DC-9-31 manufactured with line number 274 in 1968 for Eastern Air Lines, registered as N8948E.

On December 27, 1987, N8948E operating as Eastern Airlines Flight 573 was damaged beyond repair after experiencing a hard landing at Pensacola Regional Airport, Florida. The fuselage opened just behind the wings, causing the aircraft to stop with the tail section resting on the runway.

## Investigation

The engine reverse-thrust systems are activated and deactivated hydraulically. The hydraulic system controlling the reverse thrust of engine #2 during Flight 494 had failed, causing the clamshell-type thrust reversers to catch the oncoming airflow, which was strong enough to pull the reverse thrust clamshells out. The safety mechanisms for preventing accidental deployment were later found to be defective.

An unintentional deployment of reverse thrust on one engine typically results in complete loss of control resulting from the sudden opposing forces from the engines on each side. However, the crew quickly identified the cause and quickly cut fuel to the engine, eliminating the reverse forces on one side. The aircraft landed safely with one engine operating. Robertson and Bellmer received the Air Line Pilots Association Superior Airmanship Award for their efforts in saving the aircraft.

## Similar events

* November 23, 1964: A Boeing 707-331 operating as Trans World Airlines Flight 800 experienced unexpected thrust-reverser deployment during its takeoff roll at Leonardo da Vinci-Fiumicino Airport, Italy. The crew aborted takeoff but the aircraft left the runway, struck a pavement roller and ignited in flames, killing 50.
* July 4, 1966: A McDonnell Douglas DC-8-52 conducting a training flight for Air New Zealand experience a thrust-reverser deployment in the #4 engine while simulating an engine failure on takeoff. Two of the five on board were killed.
* February 9, 1982: Japan Air Lines Flight 350 crashed just before landing at Haneda Airport after the captain intentionally deployed the thrust reversers. The captain was tried in court but judged not guilty by reason of insanity, as he was diagnosed with paranoid schizophrenia. Of the 174 people on board, 24 were killed.
* May 26, 1991: A Boeing 767-300 operating as Lauda Air Flight 004 experienced an uncommanded reverse-thrust deployment while cruising that caused the aircraft to spin and stall, killing all 223 people on board.
