Glasgow

It is believe the pilot-in-command over-rotated for unknown reason.

The reason why the aircraft bounced on landing could not be determined with certainty. However, it was understood that the left engine partially lost power or failed during initial climb for unknown reason. This caused the aircraft to stall and to crash as the failure occurred at a critical stage of flight (low speed and low altitude).

The pilot did not appreciate that the aircraft had rapidly lost height whilst he was making a visual half circuit to land. This could not have been due to the absence of sufficient visual reference in the prevailing conditions of darkness, very low cloud and drizzle. The urgent nature of the flight is considered to have influenced the pilot's decision to land.

An error of airmanship on the part of the captain. During an instrument approach at night he permitted the aircraft to descend below the approved safety height and this resulted in the aircraft striking the ground.

The first and preponderant cause among those which contributed to the accident was the failure of the master rod bearings of the starboard engine. This failure could not have been foreseen or guarded against by any greater exercise of vigilance that could reasonably have been required of the operators and their staff. The secondary causes are harder to assess and evaluate. Among them are or may be:
a) The failure of pilots to make an immediate visual landing upon realizing that they must stop the starboard engine;
b) The failure of the pilots to make use of SBA although equipment was carried in the aircraft. SBA would not have been subject in this instance to the disadvantages of GCA ("presence of a mass of permanent echoes which obscure on the visual display returns from aircraft within the irregularity bounded area of sky, covered by those echoes");
c) The failure of the pilots, having elected to make use of GCA, to retract the undercarriage while flying away from the airport over the distance necessary to bring their aircraft under the effective control of GCA and thereafter;
d) The glazing of the lead deposits on the sparking plugs of the port engine while under conditions of high power-output leading to ignition trouble and so to a lose of power sufficient to destroy the ability of the aircraft to maintain level flight;
e) The necessity for taking drastic action with the controls to avoid the steeple of Harrow-on-the-Hill Church, and the high ground beyond, at a time when there was but a marginal reserve of power for maintaining level flight.

The accident was the result of a midair collision. Since neither aircraft took any apparent avoiding action it must be concluded that the pilot of the Anson did not see the Dakota and that the pilots of the Dakota did not see the Anson. This must be attributed to failure on the part of the captain of each aircraft to ensure the maintenance of an effective lookout.

Poor judgement on part of the captain who continued the approach at a too low altitude to maintain a safe distance with the ground. The failure to receive the outer marker beacon signal was considered as a contributory factor, as well as the low visibility caused by marginal weather conditions.

The accident was due to the aircraft flying into trees in conditions of poor visibility while the pilot was attempting a visual or bad weather timed approach (or circuit) to the airport. The pilot committed an error of judgement in not asking for diversion to another airport after he had failed to land by the aid of the Beam. An incorrect altimeter setting cannot be dismissed as a possible contributory cause.

It was determined that the crew did not prepare the flight properly and forgot to remove the snow on the aircraft prior to takeoff. Due to snow falls, the fuselage, wings, elevators and tail were covered by snow. Thus, the performances were reduced, the aerodynamic properties were modified, the airspeed was insufficient, the total weight was to high with too much drag as well.