What happened
On June 19, 2014, at approximately 19:00 UTC, an Aero Boero AB-180, registration PP-FLU, departed from the Cruz Alta Aerodrome (SSAK) in Rio Grande do Sul, Brazil. The aircraft, operated by Aeroclube de Cruz Alta, was performing a local flight for the purpose of glider towing.
Shortly after takeoff, at an altitude of approximately 300 feet, the aircraft lost lift. The glider pilot observed an abnormal attitude from the towing aircraft and immediately disconnected the tow cable, subsequently performing an emergency landing in an open field. The towing aircraft, however, struck a tree before impacting the ground. The impact resulted in substantial damage to the fuselage, wings, landing gear, and engine group. The pilot sustained light injuries, while the passenger remained uninjured.
The investigation
The CENIPA investigation focused on the aircraft's performance and the pilot's flight parameters. Investigators analyzed video footage that captured the entire sequence from takeoff to the crash. The investigation established that the aircraft had departed exceeding its Maximum Takeoff Weight (MTOW). Furthermore, due to the presence of a passenger, the Center of Gravity (CG) was positioned near the aft limit.
Analysis of the flight footage revealed that the pilot utilized an excessively high pitch angle immediately following takeoff. These combined factors led to a rapid loss of airspeed, resulting in an aerodynamic stall and subsequent loss of control.
Findings
- The aircraft was operating outside of its permitted weight and balance limits.
- The pilot's flight planning and judgment were insufficient for the operational conditions.
- The pilot lacked sufficient experience in the specific aircraft model, having only 6 hours of flight time in the AB-180, with only 5 of those hours completed during a glider tow training course.
- The pilot's application of flight controls failed to correct the developing stall condition.
Safety action
CENIPA issued a safety recommendation to the National Civil Aviation Agency (ANAC) to study the necessity of establishing a minimum number of flight hours in a specific tow aircraft model within the RBAC No. 61 regulations. The goal is to ensure that pilots initiating glider tow training possess enough experience to effectively identify and correct abnormal or emergency situations.