What happened
On March 2, 2012, a Pilatus PC-12/47, registration PP-SAM, was performing a private flight from Lins Aerodrome (SWXQ) to Campinas (SDAM) with two crewmembers and three passengers on board. During the takeoff roll from runway 32, the aircraft encountered severe meteorological instability.
As the aircraft climbed, it experienced abrupt and significant airspeed fluctuations. These variations were driven by intense wind gusts and a sudden change in wind direction. The aircraft's speed decreased so drastically that the stall warning and stick pusher system activated, forcing the aircraft back toward the ground. The impact occurred approximately 120 meters from the runway centerline in an irregular grass area. The aircraft veered to the right, traveling through a small depression before coming to a stop. While the aircraft sustained substantial damage—including damage to the engine, wings, flaps, fuselage, and landing gear—all five occupants escaped without injury.
The investigation
CENIPA's investigation focused on the meteorological conditions and the crew's decision-making process. Investigators analyzed data from nearby meteorological stations, which showed significant wind gusts between 22 and 32 knots, including a tailwind component of 27 knots during the takeoff phase. Satellite imagery and SIGWX charts confirmed the presence of significant thunderstorm activity and cumulonimbus clouds in the region.
The investigation examined the aircraft's performance, noting that the speed gradients observed were consistent with a windshear event. Investigators also reviewed the crew's actions during taxiing, noting that they had observed changes in wind direction but proceeded with the takeoff using 30-degree flaps to accommodate the reduced takeoff distance.
Findings
- Adverse meteorological conditions: The presence of intense windshear and significant wind gusts (up to 32.2 kt) directly caused the loss of airspeed and subsequent stall.
- Decision-making process: The decision to proceed with the takeoff was a contributing factor, as the crew had observed wind direction shifts during taxiing and encountered rain during the takeoff roll.
- Flight planning: The investigation noted that more thorough consultation of meteorological products for nearby aerodromes might have revealed the deteriorating weather conditions.
- Lack of onboard systems: The aircraft was not equipped with an onboard windshear detection system, which could have provided the crew with the necessary data to execute an abortive decision.