What happened
On August 28, 2006, a TL-32 Typhoon ultralight aircraft, registration CS-UEX, was conducting a training flight at the Espinho Municipal Aerodrome in Portugal. The flight was intended for flight instructor and student pilot training to meet requirements for license revalidation.
During the 14th takeoff of the session, while the aircraft was at an altitude of approximately 300 feet, the engine began to fail and subsequently stopped running. The flight instructor took control of the aircraft, performed a 180-degree turn, and executed a landing on a paved area used for vehicle circulation, which was located at the end of the runway and closed to air traffic at the time. The landing was successful, and both pilots remained uninjured. The aircraft sustained no damage during the event.
The investigation
The GPIAAF examined the aircraft and the engine following the incident. The investigation confirmed that the aircraft had sufficient fuel on board, the fuel lines were unobstructed, and the ignition system was functioning correctly. Subsequent tests showed that the engine operated normally once the cylinder head temperatures had decreased.
The investigation also noted that the flight had lasted three hours and included 14 takeoffs and landings in quick succession. The investigators reviewed manufacturer documentation, which highlights various scenarios involving unexpected engine shutdowns due to cooling issues.
Findings
- The engine failure was attributed to excessive cylinder head temperature accumulation caused by insufficient cooling.
- The high frequency of takeoffs and landings (14 cycles in a short period) meant the engine was constantly operating at high power settings during takeoff and climb, with insufficient time between intervals for heat to dissipate.
- The accumulation of heat likely increased friction during piston movement, leading to the engine stoppage.
- There were no mechanical failures, fuel starvation, or ignition anomalies identified.