Accident Sequence
The aircraft departed RAF Northolt at 1538 local time on a regular service to Glasgow-Renfrew. Shortly after takeoff, while climbing to an altitude of 500 feet, the crew encountered technical problems with the right engine, which was shut down and its propeller feathered. The pilot contacted ground and obtained authorization to return for an emergency landing.
While descending to runway 26 with the left engine operating only and the undercarriage down, the aircraft lost height, contacted trees, and crashed in flames in Mill Hill, approximately nine miles northeast of the airbase. The aircraft was destroyed by impact forces and a post-crash fire. One crew member was seriously injured, while all 28 other occupants were killed.
Probable Cause
The official investigation identified the first and preponderant cause as the failure of the master rod bearings of the starboard engine, which could not have been foreseen or guarded against by any greater exercise of vigilance reasonably required of the operators and their staff. Secondary causes, harder to assess, included: a) the failure of the pilots to make an immediate visual landing upon realizing the need to stop the starboard engine; b) the failure of the pilots to use SBA (Standard Beam Approach) despite carrying the equipment, which would not have been subject to the disadvantages of GCA (Ground Controlled Approach) due to permanent echoes on the visual display; c) the failure of the pilots, having elected to use GCA, to retract the undercarriage while flying away from the airport over the necessary distance to bring the aircraft under effective GCA control; d) glazing of lead deposits on the spark plugs of the port engine under high power output, leading to ignition trouble and loss of power sufficient to destroy the ability to maintain level flight; e) the necessity for drastic control action to avoid the steeple of Harrow-on-the-Hill Church and the high ground beyond at a time of marginal power reserve.