What happened
On January 14, 2018, a Cessna 152, registration PR-SKK, was performing a local flight instruction mission departing from Aeródromo Comandante Rolim Adolfo Amaro (SBJD) in JundiaI, Brazil. The crew consisted of a flight instructor and a student pilot.
During the takeoff roll on runway 18, the engine RPM stabilized at approximately 2,200 RPM, and the aircraft rotated at the expected speed of 60 knots. However, the aircraft failed to gain airspeed during the initial climb. Upon reaching 200 feet, the airspeed dropped rapidly to 40 knots, triggering the stall warning. Realizing the engine was not providing sufficient performance to continue the flight, the instructor initiated an emergency procedure, performing a forced landing in a cornfield approximately 1.5 km from the threshold of runway 36. During the landing, the nose gear collapsed, causing the aircraft to capsize. The aircraft sustained substantial damage, while the instructor sustained minor injuries and the student remained uninjured.
The investigation
CENIPA investigators examined the engine, fuel, and oil samples. Laboratory analysis confirmed that the fuel and oil met all specifications and showed no signs of contamination. Mechanical inspections of the engine revealed no internal failures or defects that would have compromised normal operation.
Investigators determined that the aircraft was approximately 3 kg above its Maximum Takeoff Weight (MTOW) at the time of departure. Furthermore, the investigation found that the carburetor heat system was active during the takeoff. According to the aircraft's operating manual, leaving the carburetor heat on can cause a reduction in engine RPM of approximately 100 to 200 RPM due to the introduction of hot air into the induction system.
Findings
- The aircraft was operating slightly above its maximum takeoff weight.
- The carburetor heat was left engaged during the takeoff phase.
- The engine RPM during the takeoff roll (2,200 RPM) was lower than the recommended range for a power check (2,280 to 2,380 RPM).
- The crew failed to abort the takeoff despite the atypical engine performance and low RPM observed during the takeoff roll.
- Errors in pilot judgment and decision-making contributed to the inability to recognize the risks of the high weight and reduced power combination.