What happened
On July 9, 2017, a Cessna F 150L departed from runway 26 at the Frankfurt-Egelsbach airfield for a private VFR flight. Shortly after takeoff, the aircraft lost altitude and crashed into a dense wooded area approximately 1.2 km beyond the end of the runway.
Witnesses observed that the aircraft took off very late on the runway and exhibited an unusually slow and flat climb. The pilot reported that the engine was not producing its expected power during the takeoff roll, resulting in sluggish acceleration. Although the pilot noticed the performance issue, she decided to continue the takeoff rather than aborting. Once the aircraft climbed out of ground effect, the insufficient climb rate became critical. To avoid crashing onto a nearby highway, the pilot attempted to steer toward a wooded area to perform an emergency landing. During this maneuver, the aircraft struck trees, overturned, and came to rest on its back, causing severe injuries to the pilot and heavy damage to the aircraft.
The investigation
The BFU investigation focused on the engine's performance and the pilot's decision-making process. Investigators examined the engine and found that all eight spark plugs showed black combustion patterns, with three plugs being oil-fouled. A compression test revealed that cylinder number 3 had no compression due to a stuck exhaust valve, and cylinder number 1 showed significantly reduced compression.
Additionally, investigators found that the carburetor heat switch was engaged. The aircraft was not overloaded, and the center of gravity was within limits. The investigation also reviewed the aircraft's maintenance history, noting that a 200-hour inspection had been performed recently to address a previous engine issue involving the replacement of an exhaust valve and related components.
Findings
- The primary cause of the accident was insufficient engine power for a safe takeoff.
- The pilot failed to execute a takeoff abort immediately after recognizing the significant loss of engine performance.
- High ambient temperatures (24°C) further contributed to the reduced engine performance.
- An abort would have been successful, as the available runway length of 1,400 meters was more than sufficient for the conditions.