KLM Royal Dutch Airlines - Koninklijke Luchtvaart Maatschappij

The exact cause of the accident could not be determined with certainty. During the extensive technical investigation no facts were found to be true for a technical failure of any part of the aircraft before the accident. The damping of the cable tensioners did not fully meet the specifications however, the Board considered that this could hardly have affected steerability. The ascent was somewhat flatter than normal and possibly created the rapid execution of the commands "flaps up" and "first power reduction" provide a greater condition steering movement required than the captain was used to. That need not be serious as long as the captain retained the confidence he had could bring back the plane in ascending flight. All in all, the investigation did not provide a clear cause for the captain Of course it is important that one of the conclusions of the Council was that “On the basis of the foregoing, the Board, together with the preliminary investigator, is of the opinion that in this case does not warrant the application of any sanction against the person is present.

Failure of a propeller blade during flight shortly before landing at Don Mueang Airport. This caused the loss of number three engine and fire to break out in the engine nacelle which could not be extinguished. When landing, the right main landing gear collapsed as a consequence of the fire.

The exact cause of the accident could not be determined with certainty. However, it is possible that the crew continued the approach below the minimum descent altitude to maintain a visual contact with the ground.

The Board was of the opinion that two successive errors of judgment were committed by the pilot. These were as follows:
- He initiated a landing procedure at an aerodrome with which he was not acquainted, in weather conditions which were lower than the minimum prescribed for landings on that aerodrome,
- Upon arrival over the aerodrome, he flew at too low an altitude over a terrain which he must have known to include a hill which constituted a hazard for his aircraft, which hill he was not able to see, on account of the poor visibility and low cloud.
The Board further considered that the following factors contributed towards the accident to a considerable extent:
- Air Traffic Control did not advise the pilot to delay his landing until the weather conditions had improved, or otherwise to divert to another aerodrome,
- Air Traffic Control designated a runway for the landing which necessitated the aircraft venturing low over dangerous terrain as indicated above.

As only few debris were found, investigations were unable to determine the exact cause of the accident. Nevertheless, it was the opinion of the experts that the loss of control may have been caused by a failure of the automatic pilot system.

It was determined that:
- When the pilot started his landing maneuver for runway 26 of Prestwick Airport the weather conditions were already below the limits for this maneuver but that from the weather forecasts received this could not be known to him and that this could not be personally judged at the time.
- That, although the landing on runway 26 under the weather conditions, as far as these were known to the pilot, required the greatest caution, the pilot could not be blamed for having commenced that landing procedure.
- That flying too long on the downwind-leg of runway 26 caused the accident.
- That, if no unknown circumstances contributed to the extension of the flight on the downwind-leg of runway 26, the extension was due to the delayed action of the pilot after he lost visual approach.
- That it was not impossible that a stronger wind that the pilot accounted for contributed to the extension of the flight on the downwind-leg of runway 26.
- That the possibility of other circumstances as mentioned under 4 could not be ruled out, but that no data was available which could give cause for the supposition that they contributed to the extension of the flight at a low altitude on the downwind-leg of runway 26.

It was determined that the captain adopted a wrong approach configuration with an insufficient approach speed with full flaps selected, causing the aircraft to stall and hit the ground short of runway threshold.

It is possible that the accident may have been caused by a fault in the time position of the screw system of the engine number one, whereby the blade angle of this screw was incorrect. Unfortunately, this could not be demonstrated conclusively. In addition of that, the reaction from the crew when the aircraft started to deviate from the path and the correction with the rudder was approximately 3.5 seconds, which lead the aircraft to become out of control.