Flight 261 Alaska Airlines

The flight ACE 261 was a flight of the company Alaska Airlines which ensured the connection between the Mexican seaside resort of Puerto Vallarta, on the peaceful coast and Seattle in the North-West of the the United States. The January 31st 2000 the apparatus, a McDonnell Douglas MD-83 was crushed in the Pacific Ocean with broad of Los Angeles. The 83 passengers and the 5 team members perished in the catastrophe.

Circumstances of the accident

The plane was a McDonnell Douglas MD-83, registered N963AS, serial number 53077, built in 1992. According to Alaska Airlines the apparatus added up 26.584 hours of flight (14 315 cycles) at the time of the accident. The weather was good and the flight left normally the airport of Puero Vallarta.

During the initial rise the crew was confronted with problems of directional control of the plane. They realized that the compensator of the elevator was blocked. The crew did not arrive to trimmer the apparatus any more, i.e. to make small adjustments on surfaces of control of flight in order to stabilize the plane vertically. The plane was always controllable but it was very difficult to make him keep its level of vol. In order to mitigate the problem the pilots tried to free the compensator with the system of principal trim and that of help. That did not have any effect. After having discussed with the engineers on the ground the company and the air-traffic controllers, the crew decided to try to rather continue their flight towards their commercial stopover of Los Angeles than to be posed on one 9 airports surrounding. This decision will be reproached to them a long time.

Once the operations of change of course carried out, the pilots continued to try to solve the problem. Seven minutes after the decision to continue towards L.A., they managed to operate the compensator. Unfortunately it was spread completely what caused to make plunge the apparatus violently. To the wholesale price efforts on the orders, the pilots managed to rectify the plane and continued the flight towards Los Angeles. They slowed down the plane in order to reduce the aerodynamic loads on surfaces of controls. After having consulted a mechanic on the ground, the pilots wondered whether the compensator had again to be actuated. They decided to leave it in place as it was. Less than one minute afterwards, approximately 10 minutes after the first dive, a noise " extremely fort" was recorded by the Block box (the CVR - Cockpit Voice Recorder) and the plane was involved in second piqué while being turned over. It struck the ocean later by disintegrating approximately 1 mn, has an estimated speed of 400 km/h. Impact take place between Anacapa Island, coastal island of California and the continental coast.

The fall was seen by people on the coast and of the pilots of other planes in approach on the international airport of Los Angeles.

Inquire

The report/ratio of investigation of NTSB, the National Transportation Safety Board , allotted the crash landing to a failure of the screw which made it possible to mount and descend the compensator from stability of the plane and whose lubrication was very insufficient. This bad lubrication involved an abnormal wear of the threading of the nut in which the screw turned. When the pilots tried to operate the compensator, the screw was not retained any more by its nut and the compensator left its operational limits. Ten minutes later, another part of the mechanism which retained the compensator broke, actuating the plane in an irremediable dive.

The NTSB foot-note which the originators of the plane had not provided back-up system if the screw has suddenly left its nut. Instead of that, they had counted on the talks to determine the degree of wear of the screw and the nut and to decide on their possible replacement. The NTSB indicated that it was not adapted to entrust to the only maintenance the role to identify an imminent rupture of such a capital component.

The investigation also showed serious negligences in the maintenance of the planes by Alaska Airlines. Thus 6 other MD-83 of the company presented the same serious defect of absence of greasing or change of the part of control surface which released on the broken plane. Alaska Airlines used also a special method for the checking of wear of the screw. The procedure given by the manufacturer of planes envisaged the use of a particular tool. In addition to this tool, the company had manufactured some in its workshops of maintenance. However those did not correspond to dimensions of the tool " officiel". Besides this company was the subject of an investigation of the American air administration following a denunciation of the head mechanic of its company of serious failure in the maintenance of the planes for reasons of economies and of a greater availability with the flight of the planes.

Pilots

Until the last moment the pilots tried to take again the control of the apparatus. The latter were tested. The captain Ted Thompson, 53 years old added up 17.750 hours of flight including 10.460 as a commander, including 4.150 with the orders of a MANDELEVIUM 80. Its copilot, Bill Tansky, 57 years old added up to him 8.140 hours of flight including 8.060 hours out of MANDELEVIUM 80. For their action during the attempt at rescue of the plane, the 2 pilots, scour the gold medal of the heroism of the Air Line Pilots Association, only time where this distinction was given on a purely posthumous basis.

Continuation

After the accident, the number of flight 261 was withdrawn and replaced by number 289.

A memorial at built summer with Port Hueneme, not far from the place of the catastrophe. It is a Sundial which projects a shade on the plate of the memorial each January 31st at 16:22, day and hour of the accident.

This accident was the subject of an episode of the documentary series tele Air Crash landing Investigation.

References

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