The German Federal Bureau of Aircraft Accident Investigation (BFU) released a report detailing an instance where pilots conducted an unauthorized roll of their Bombardier Learjet 31A air ambulance aircraft. No one was injured when the pilots of the aircraft performed the maneuver with two company employees aboard near Faro, Portugal, on Dec. 28, 2018. But both pilots were fired as a result of the incident.
According to the BFU, the aircraft, which is operated by a German carrier, had taken off from London Biggin Hill on a flight to Faro. After about an hour into the flight, the pilot-in-command—who occupied the left-hand seat and was the pilot flying—asked the copilot if he agreed to fly a roll. The copilot maintains that he did not agree to such a flight maneuver. He further said, and flight data record data indicated, that the PIC had disengaged the autopilot at about 13,200 feet and flew the airplane manually. At about 11,500 feet, the aircraft entered two steep turns with a bank angle of about 140-degrees each, then the “PIC conducted the roll about the longitudinal axis of the airplane,” leveling off 10 seconds later.
The roll started as the airplane flew at 301 knots indicated airspeed, which decreased continuously and leveled off at 251 KIAS. According to the report, the Learjet reached a maximum load of +2.47 g during the initiation of the maneuver. The aircraft operations manual prohibits the use of aerobatic maneuvers, BFU said.
This maneuver was discovered in May 2019 during a routine read-out of FDR data, which showed “the exceptionally high roll angle.” The occurrence was reported to the operator, which then inspected the aircraft but found no damage. The operator also “promptly released the PIC and the copilot from their flying duties and terminated the employment contract after the occurrence became known.”
The incidence followed a similar occurrence of a flight maneuver, but in that case, the aircraft, a Cessna Citation 550B Bravo, crashed and both pilots were killed. That incident, which occurred in 2010 Switzerland, involved a roll initiated at FL270. However, that crew lost control of the aircraft and it turned steeply toward the ground. The maneuver was prohibited by the manufacturer and the pilots were neither licensed nor certified to perform it.