What happened
On May 19, 2002, a PZL M18A Dromader, registration EC-FDM, was performing aerial application services at a provisional runway in Isla Mayor, Seville. Following a routine landing, the pilot proceeded along the runway toward a cargo hangar. While attempting to execute a 90-degree turn to reach the hangar, the aircraft drifted beyond the intended path and struck the wall of a warehouse with the tip of its right wing.
The impact caused the propeller blades to contact the wall and resulted in major damage to the aircraft. The right wing sustained structural failure, including a broken rib near the inner flap, deformation of the leading edge, and compression of the wing surfaces. Internally, various control linkages, ribs, and conduits were broken. The pilot was uninjured during the event.
The investigation
The investigation focused on the aircraft's braking performance and the functionality of the hydraulic system. The pilot reported a perceived lack of braking effectiveness during the turn, though no warning lights or system failures were observed in the cockpit.
Investigators examined the hydraulic installation, which powers the flap controls, main wheel brakes, atomizers, and the pump winch. The system relies on an engine-driven variable-displacement pump and a hydraulic accumulator for emergency pressure. The hydraulic pump in use had only 651 total flight hours, having been installed just 25 hours prior to the accident.
Findings
- The investigation established that the loss of braking effectiveness was the primary factor in the collision.
- It is highly probable that the use of the flaps and brakes during the landing roll depleted the hydraulic pressure stored in the accumulator.
- Because the hydraulic pump was unable to replenish the accumulator pressure sufficiently at low engine RPMs, the braking efficiency decreased during the subsequent turn, leading to the impact.