Investigation Summary
On the morning of March 27, 1951, Manchester was experiencing heavy snowfall and freezing temperatures. The Air Transport Charter Dakota, registered G-AJVZ, was prepared for a routine mail and newspaper run to Northern Ireland. Despite the weather, the pilot did not clear accumulated snow from the airframe before attempting departure. During the takeoff run on Runway 06, the aircraft remained on the ground until nearly the end of the 1,400-yard runway. Once airborne, the Dakota swung to port and failed to gain significant altitude. Approximately half a mile from the runway end, the aircraft struck the top of a tree in Woodhouse Lane near the hamlet of Heyhead, stalled, and crashed into a field. The impact killed both pilots and seriously injured the third occupant. Post-crash analysis of the wreckage revealed soot deposits in the engines, indicating backfiring caused by an improper fuel-air mixture. Crucially, the carburetor intake screens were found distorted in a manner consistent with being packed with frozen snow or ice, which severely restricted airflow and engine power output.
Final Conclusions
The investigation concluded that the primary cause was the loss of engine power due to ice formation in the carburetor intakes, directly attributable to the captain's failure to utilize the heat controls. Contributory factors included the aerodynamic degradation caused by snow remaining on the wings and the increased drag from the undercarriage, which remained extended during the brief flight.
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Systems & Failure Modes
Carburetor Heat Controls
A system designed to divert heated air into the carburetors to prevent or melt ice accumulation; the captain's failure to engage this system led to engine power loss.
Carburetor Intake Screens
Protective screens that became packed with frozen snow, restricting the air-fuel mixture and causing the engines to backfire.
Interesting Facts
- 01The aircraft was a 1943-built Douglas C-47A-75-DL Dakota 3.
- 02The aircraft's Manufacturer Serial Number (MSN) was 19361.
- 03The flight was a non-scheduled cargo operation carrying mail and newspapers.
- 04Weather at the time of the accident included heavy snow and freezing temperatures.
- 05Post-crash inspection found carburetor intake screens distorted by ice and snow packing.
- 06The investigation noted that the pilot failed to use carburetor heat controls to melt the ice.
Safety Actions & Advisories
Carburetor Heat Operational Procedures
The accident highlighted the critical necessity of using carburetor heat controls during takeoff and climb in icing or heavy snow conditions to prevent engine power loss, as specified in the aircraft's operating manual.