Air Accidents Investigation Branch
Summary:
After takeoff the engine in G-CJZU suffered a partial power loss. This power loss became more significant as the aircraft reached 300 ft aal. The aircraft had little natural stall warning and was not fitted with an artificial stall warning device. A safe flying speed was not maintained, and the aircraft departed from controlled flight at a height from which it was not possible to recover. The aircraft descended steeply and struck the ground nose first. The accident was not survivable.
Examination of the engine could not find any faults that could have caused or contributed to the loss of power. The aircraft had sufficient fuel for the flight. Insufficient supply of fuel to the engine from the tanks could have caused the power reduction but the damage to the aircraft meant that it was not possible to establish the condition of the fuel system or level of fuel supply. It is also possible that a fault in the ignition system could have contributed to the power reduction, but the damage from the post impact fire meant that the integrity of the electrical system could not be fully assessed. Weather conditions were also conducive to carburettor ice forming on the taxi out to the runway. It is possible that carburettor ice formation caused the engine to lose power after takeoff.
Whilst the investigation of G-CJZU was in progress, a further event involving partial power occurred in which the three occupants of the aircraft were seriously injured. The aircraft suffered a partial loss of engine power shortly after takeoff and the pilot attempted a turnback to land on the reciprocal runway. The aircraft stalled during the turn and struck the ground west of the runway. Three Safety Recommendations were made in that report with respect to pilot training for partial power loss events. These Safety Recommendations, whilst not a part of this report, were formed on the basis of information from both accidents and are supported by the events described here.