What happened
On July 19, 2016, a DR400-120, registration G-GBUV, was preparing for a flight from Valenciennes aerodrome to Chambley. The aircraft, carrying a pilot and one passenger, was operating near its maximum takeoff weight. During the takeoff roll on runway 11, the pilot noted that the aircraft felt sluggish despite a normal engine RPM. After traveling approximately 500 meters, the indicated airspeed reached only 40 knots, well below the 54-knot rotation speed.
Deciding to abort the takeoff, the pilot turned the aircraft around to attempt a second departure. During this turnaround, the aircraft suddenly came to a halt as if the wheels were locked. The pilot then heard a small explosion near the left side of the aircraft, followed by black smoke and flames emerging from beneath the left wing. The crew successfully evacuated the aircraft, but the DR400-120 was destroyed by the resulting fire.
The investigation
The investigation focused on the mechanical state of the landing gear and braking system. Because the fire was so intense, the landing gear and braking circuit could not be examined directly. However, investigators noted that the explosion heard by the pilot was likely the left tire bursting due to extreme heat.
The aircraft was equipped with an older central brake handle system, which applies brakes to both main wheels simultaneously. Investigators also reviewed historical data regarding similar incidents in DR400 models, noting that several previous events involved this specific braking configuration, often occurring after long taxiing or aborted takeoffs, particularly in high ambient temperatures.
Findings
Several factors contributed to the accident:
- The pilot's use of the central brake handle during engine tests may have resulted in residual braking if the pressure was not fully released from the circuit.
- This residual braking caused significant heat buildup in the brakes during the initial takeoff roll.
- High ambient temperatures (31 °C) likely exacerbated the overheating of the left main gear.
- The large amount of available runway length may have caused the pilot to delay the decision to abort the takeoff, allowing the heat to build up further.