What happened
On October 26, 2021, a Learjet 35A, registration LV-BPO, operated by Dos Mil Aerosistemas S.A., was involved in a ground incident at San Fernando International Airport in Buenos Aires. The aircraft was performing a non-scheduled commercial sanitary flight. After completing a previous flight shortly before the event, the crew prepared for a new departure. During the initial takeoff roll, the pilot observed an engine temperature indication outside of limits on the right engine and decided to abort the takeoff at a speed between 7 and 80 knots.
Following the first abort, the crew attempted a second takeoff 11 minutes later. During this second attempt, the same temperature indication recurred, leading the pilot to abort the takeoff a second time. While taxiing toward the hangar area via taxiway Alpha, the crew noticed white smoke emanating from the landing gear and experienced difficulty with directional control. Upon stopping the aircraft, the crew identified fire at the left main landing gear and utilized the onboard extinguisher to suppress the flames. There were no fatalities and no injuries to the crew or passengers.
The investigation
The investigation conducted by the JST examined cockpit voice recordings, air traffic control communications, and the aircraft's maintenance and flight manuals. Investigators focused on the sequence of the two aborted takeoffs and the thermal state of the braking system. The inquiry reviewed the manufacturer's specifications regarding the temperature thresholds for the wheel hub fuse plugs, which are designed to release tire pressure if temperatures exceed approximately 182°C to prevent catastrophic failures.
Findings
- The aircraft's brakes retained residual heat from the preceding landing.
- The interval between the first and second aborted takeoffs was only 11 minutes.
- The crew failed to observe the mandatory 20-minute waiting period and visual inspection of the tires, hubs, and brakes required by the flight manual after an aborted takeoff between 40 and 80 knots.
- Excessive heat caused the fuse plugs in the left and right main landing gear hubs to activate, resulting in tire deflation.
- The high temperature, combined with brake dust from friction, ignited a small fire in the left main landing gear assembly.