What happened
On September 19, 1993, an AIRLEC Fairchild SA227 Metro III, registration F-GILN, was preparing for a passenger charter flight from Troyes-Barberey to Biggin Hill, England. The aircraft was carrying two crew members and 17 passengers.
During the takeoff roll on runway 18, the aircraft reached approximately 100 knots when the co-pilot observed a significant power drop in the right engine, with thrust falling from 93% to 40% accompanied by a sharp rise in Exhaust Gas Temperature (EGT). The pilot experienced a strong rightward yaw and, having not yet reached $V_1$, elected to abort the takeoff.
During the high-speed braking phase, the aircraft veered toward the left edge of the runway. The crew attempted to use reverse thrust on the left engine, but the effectiveness of the reverser was insufficient, and the aircraft actually experienced a slight acceleration. To manage the situation, the crew shut down the right engine and subsequently the left engine as the runway end approached. The aircraft exited the paved surface, struck a radio beacon antenna, breached the airfield perimeter, and eventually came to rest in a plowed field. The aircraft sustained 80% damage.
The investigation
The BEA investigation focused on the cause of the engine power loss, the accuracy of the takeoff performance calculations, and the effectiveness of the braking.
Investigators examined the engines and found evidence of severe overheating in both turbines, though no mechanical failure or external cause for the temperature spike was identified. The investigation also scrutinized the aircraft's weight and balance. While the crew believed the aircraft was at its maximum takeoff weight of 14,500 lbs, the actual takeoff mass was approximately 15,158 lbs. This discrepancy was due to an outdated empty weight recorded in the operating manual and unweighed baggage.
Furthermore, the investigation looked into the braking performance. While the crew applied maximum braking pressure—deforming the brake pedal rods—the braking was hindered by a buildup of hydraulic fluid and engine oil on the brake discs and linings.
Findings
- The primary cause of the engine power loss was overheating of both turbines, potentially caused by an error in the positioning of the speed levers during takeoff.
- The aircraft was operating significantly overweight, exceeding the maximum allowable takeoff mass by 658 lbs.
- The aircraft was in an aft center-of-gravity configuration.
- Braking effectiveness was reduced due to contamination of the brake components with oil and hydraulic fluid.
- The crew's experience on the Fairchild SA227 type was extremely limited, with the pilots having held their type ratings for only 11 and 12 days, respectively.
- The takeoff performance calculations were inaccurate because the crew relied on an outdated aircraft empty weight and did not weigh the baggage.