What happened
On December 13, 2014, a Cessna 182J, registration HB-CBZ, was engaged in a private VFR flight for the purpose of dropping skydivers at Luzern-Beromünster (LSZO). The aircraft was configured for the operation with all seats and seatbelts removed except for the pilot's seat. The pilot was carrying four passengers who were seated on the aircraft floor without restraints.
During the takeoff roll on a wet and partially frozen grass runway, the aircraft failed to reach the necessary rotation speed. The pilot observed a drainage ditch ahead and, rather than aborting the takeoff, continued at maximum power. As the aircraft approached the ditch, the pilot pulled the control column back sharply. The Cess0182J lifted off, crossed the ditch, and struck the embankment. The aircraft subsequently impacted the soft, wet field, causing the nose gear to collapse and the propeller to strike the ground. The sudden deceleration caused the unrestrained passengers to be thrown forward; one passenger was pushed under the instrument panel, while others were thrown against the pilot's seat with enough force to tear the seat from its tracks. One passenger was even ejected from the aircraft through the open door.
The investigation
SUST examined the aircraft's weight and balance, the runway conditions, and the pilot's preparation. The investigation established that the aircraft's takeoff mass was approximately 3045 lb, which exceeded the maximum allowable takeoff weight of 2800 lb. Furthermore, the investigation found that the pilot had not requested permission to use the runway extension, which would have provided the necessary distance for a safe takeoff. The investigation also noted that the pilot's flight preparation was insufficient regarding the assessment of the runway's soft condition and the aircraft's performance limits.
Findings
- The accident was caused by a runway overrun resulting from an un-interrupted takeoff with excessive mass on a soft runway surface.
- The pilot failed to abort the takeoff despite the aircraft's inability to reach rotation speed on the slippery grass.
- The aircraft was operating significantly above its maximum allowable takeoff weight.
- Inadequate flight preparation contributed to the event, specifically regarding the assessment of the runway's state and the lack of a runway extension permit.
- The absence of a restraint system for the skydivers contributed to the severity of the impact, as the force of the passengers being thrown forward caused the pilot's seat to detach from its tracks.
Safety action
- Safety Recommendation No. 497: The authorities (BAZL and EASA) should implement measures to ensure that occupants of aircraft are secured during takeoff, landing, and turbulence, even during special operations such as skydiving.
- Safety Notice No. 4: Pilots are advised to establish clear 'go/no-go' decision points for takeoffs on grass runways, particularly when operating near performance limits.