What happened
On August 21, 2018, a Cessna 150M, registration LV-CZA, was conducting a flight training mission near Lozada, Córdoba, when it experienced a loss of control. The aircraft, occupied by a flight instructor and a student pilot, departed from the Coronel Olmedo Aerodrome at 12:15 UTC.
Approximately 35 minutes into the flight, while performing a climb at maximum power, the aircraft's pitch angle increased to 32 degrees. This maneuver caused the aircraft to exceed its critical angle of attack, leading to an aerodynamic stall. The stall was accompanied by a lateral slip, which was attributed to the student pilot's rudder technique.
As the aircraft entered a spin, the crew attempted recovery maneuvers that deviated from the manufacturer's recommended procedures. The aircraft completed six full rotations during the spin without regaining controlled flight, ultimately impacting the ground. The impact resulted in the total destruction of the aircraft and the two fatalities of both occupants.
The investigation
The Argentine investigation examined the flight profiles, the technical capabilities of the Cessna 150M, and the training environment. Investigators noted that while the aircraft was maintained according to manufacturer standards, the 150M model is not certified for acrobatic maneuvers, including intentional spins.
The investigation also reviewed the instructor's credentials and the student's progress, noting the student was on his third lesson of a private pilot course. The inquiry looked into the cockpit dynamics, specifically why corrective actions were delayed. It was determined that the instructor was heavily focused on monitoring the student's coordination of flight controls, which delayed the initiation of recovery inputs.
Findings
- The aircraft exceeded its critical angle of attack during a high-power climb.
- A lateral slip, caused by the student pilot's rudder usage, intensified the stall condition.
- The delay in initiating recovery actions and the use of incorrect techniques—such as applying aileron to lift the dropped wing and maintaining continuous back pressure on the elevator—directly led to the development of the spin.
- Current regulations do not mandate the practice or demonstration of stall recovery or unusual attitude maneuvers during initial flight training or instructor certification.
Safety action
Following the investigation, the following recommendations were made to the National Civil Aviation Administration (ANAC):
- Amend existing regulations to require a practical demonstration of stall recovery techniques during the initial flight instructor certification exam and during periodic proficiency checks.
- Urgently publish a specific pilot guide for the prevention and recovery of loss of control in general aviation, aligned with modern international standards.