What happened
On June 1, 2008, a Piper PA-18180D, registration CS-AII, operated by Aero Clube de Coimbra, departed from runway 24 at the Covilhã Municipal Aerodrome for a local flight intended as a flight experience for three passengers. During the initial climb, at approximately 400 feet AGL, the engine experienced a sudden loss of power. Although engine instruments for pressure, temperature, and fuel showed normal parameters, the pilot immediately attempted to execute a 180-degree turn to land on the opposite runway (06).
However, the pilot's plan to land on runway 06 was obstructed by another aircraft that had already begun its takeoff roll from that runway. Forced to continue the flight with insufficient power, the pilot attempted to return to runway 24. Due to the continuous loss of altitude, the pilot was unable to maintain a safe altitude for a standard approach and instead performed a low-speed, oblique approach. The aircraft entered a stall with the right wing low, impacting the unpaved ground beside runway 24. The aircraft bounced, slid across the runway pavement, and eventually came to a stop. There were no injuries to the pilot or passengers, and the aircraft sustained no damage.
The investigation
The GPIAAF investigation examined the engine performance and cockpit procedures. Following the incident, ground tests were conducted on the engine. During a checklist review in the presence of the pilot, investigators discovered that the carburetor heat control was left in the ON position. When the control was corrected to the OFF position, the engine operated normally during subsequent ground tests and a test flight. The investigation also reviewed the aircraft's maintenance records, which were found to be valid and up to date, and noted that the aircraft had no prior history of engine anomalies.
Findings
- The primary cause of the power loss was an improper air-fuel mixture in the carburetor caused by the carburetor heat being left in the ON position during takeoff.
- A contributing factor was the pilot's failure to follow the takeoff checklist, specifically the item requiring the carburetor heat to be set to OFF.
- The investigation noted that the pilot's attention may have been diverted by the presence of passengers during the flight experience, or there was a lack of discipline in strictly following the mandatory checklist procedures.