What happened
On September 15, 2007, at approximately 16:30, a KP2U-SOVA-RAPID 200 ultralight aircraft crashed in Fenyuan Township, Changhua County. The aircraft, carrying a pilot and one passenger, took off from an unauthorized landing site near Limin Bridge. Shortly after liftoff, at an altitude of approximately 40 feet, the propeller stopped rotating, and the aircraft entered a leftward descent. The aircraft struck a slope near a field embankment approximately 400 meters from the takeoff point. The impact caused severe damage to the nose and left wing. The pilot sustained serious injuries and fell into a coma, while the passenger suffered broken legs.
The investigation
The investigation examined the aircraft's mechanical condition, the engine's maintenance history, and the pilot's emergency response. Investigators found that the aircraft's engine, a ROTAX 912 ULS, was a non-certified engine. While the engine had records of initial installation, there were no records of original flight testing or subsequent maintenance beyond the initial setup.
Physical examination of the wreckage revealed that the propeller blades were not in a rotating state at the moment of impact. Analysis of the fuel system showed that the mechanical fuel pump mounting was damaged and the fuel lines to the carburet_uretors had disconnected. Furthermore, measurements of the carburetor float bracket gaps showed values (0.80mm and 1.05mm) significantly higher than the manufacturer's specification of 0.4mm to 0.5mm. Additionally, the investigation found that the mechanical fuel pump installed was a part number that had been subject to a mandatory service bulletin (SB-912-053UL) requiring replacement to prevent engine failure.
Findings
- The engine failure was likely caused by an excessively rich fuel mixture resulting from carburetor float bracket gaps that exceeded manufacturer specifications.
- The aircraft was operating with a mechanical fuel pump that had not been replaced in accordance with the manufacturer's mandatory service bulletin.
- The pilot failed to follow established emergency procedures; instead of maintaining airspeed and attempting to land straight ahead or in the direction of takeoff, the pilot attempted a left turn, which led to a stall and subsequent crash.
- The aircraft was being operated in an unauthorized airspace and at an unapproved landing site.
- The pilot and passenger were operating the aircraft without valid ultralight pilot certificates.
- The engine used was a non-certified type, which carries an inherent risk of sudden failure.