History of the Flight
The pilot arrived at Sherburn Airfield in the afternoon to collect his aircraft, which had been at the airfield for one week for installation of a new intercom unit. After inspecting the unit and completing pre-flight checks, the pilot found an engineer re-attaching the plastic knob of the flap selector switch with glue. The towing arm was removed from the rear seat and stowed in the baggage compartment. After consulting weather information, the pilot decided to refuel. He removed the towing arm, connected it to the nosewheel, and with assistance from the refueller, manoeuvred the aircraft to the fuel pumps. Twenty litres of fuel (10 per side) were loaded. The refueller noted fuel already in both tanks but did not know the total. After refuelling, the pilot secured the fuel caps, the aircraft was pushed back, and the refueller removed the towing arm and handed it to the pilot. No one saw the towing arm being stowed, but it was later found in the baggage bay after the accident.
At about 1515 hrs, the pilot entered via the left door and started the engine. After a brief period, he began taxiing. The refueller guided him past other parked aircraft from the right side and could not see the baggage compartment door. The aircraft taxied to the threshold of Runway 19 and commenced takeoff.
During the initial takeoff roll, three witnesses noticed a large hole in the left fuselage behind the wing trailing edge and deduced the baggage door was open or missing. The Chief Flying Instructor (CFI), watching from the operations room, informed the pilot by radio that the baggage door appeared open. The pilot replied he was unaware but would return to land. The aircraft immediately began a right turn. The CFI estimated the turn started at about 500 ft agl and descended to about 250 ft agl. The turn was steep, estimated at 40° bank, and the aircraft turned 180°. It remained low and close to the runway, flying slowly.
As the aircraft approached abeam the Runway 19 threshold, it started a right turn. The bank angle rapidly increased to an estimated 80°, and the nose pitched up. Engine noise increased rapidly. The CFI activated the crash alarm. The aircraft struck the ground vertically, and a fire started. Airfield fire vehicles arrived within two minutes and brought the fire under control.
The pilot sustained fatal injuries. A post-mortem found no pre-existing disease that could have caused or contributed to the accident.
Meteorological Conditions
The synoptic situation featured an unstable westerly airflow with heavy showers; conditions were good outside showers. At the time of the accident, surface wind was 280°/6-8 kt, visibility greater than 10 km, cloudbase 1,500–2,000 ft, with showers in the vicinity but not over the airfield.
Pilot's Experience
The pilot began flying training in the Royal Air Force in 1953, completing 145 hours by 1954. He resumed flying in 1992, gaining a Private Pilot's Licence and an IMC rating the following year. At the time of the accident, he had 690 hours total, 420 on the Socata TB10. Most recent flying had been on G-BKTY, with 9 hours 30 minutes since October 2000.
Aircraft Information
The Socata TB10 Tobago is a single-engine, low-wing monoplane with non-retractable tricycle landing gear. Controls are manual via control rods. Flaps are electrically operated via a motor driving a screw jack. The two-bladed propeller is variable pitch. The aircraft had a single-axis autopilot providing heading hold and navigation.
Wreckage and Impact Information
Ground impact marks indicated the aircraft struck the ground on a heading of about 180°(M) in a wings-level, near-vertical pitch attitude. Propeller slash marks showed the engine was developing power. The nose was destroyed, wings severely damaged, and fuel ignited immediately. The propeller separated from the crankshaft; the engine was found 2 metres from the impact crater. The main part of the aircraft slid about 15 metres backwards before coming to rest. The aircraft was destroyed in the ground fire. No objects were found fallen from the flight path. All flight control surfaces were attached, and control rods and trim cables were connected at impact.
Engine examination on site showed no catastrophic failure. Ancillary components were attached except the carburettor and air pump, which broke off on impact. The baggage door was still attached with hinges intact, in the open position, with the upper part embedded in the ground. The lock was undamaged and found in the unlocked detent. The towing arm was found in the baggage compartment.
Examination Findings
Flight control mechanisms were disrupted by impact and fire, but no pre-impact failure was found. The flap drive screw jack was fully retracted (flaps up). The flap selection lever knob, re-attached before flight, could not be identified, consumed in the fire. Instruments were destroyed. The engine showed no external failure; internal drive train continuity and compression on all cylinders were confirmed. A fuel sample from the storage tank complied with AVGAS 100LL specifications and was free from contamination.
An examination of a similar TB10 baggage door showed that a badly worn lock could allow the door to pop open from vibration. However, the lock on G-BKTY was found in the unlocked detent, ruling out that scenario. Persons familiar with G-BKTY stated the door required a positive effort to close and lock, making it unlikely but not impossible that the pilot only partially locked the door before takeoff.