Engine failure leads to helicopter crash during external load operation in Hannover

Casualties unknown • Hannover, DE

An Eurocopter AS350 B2 sustained heavy damage after the pilot performed an autorotative landing on a factory roof following an engine failure caused by fuel starvation.

What happened

On September 10, 2011, an Eurocopter AS350 B2 helicopter was engaged in external load operations near a factory in Hannover-Stöcken, Germany. The pilot had been performing a series of nine transport flights, moving loads from a staging area next to a workshop to the roof of the building. The flight path for each trip was only a few hundred meters.

During the tenth transport mission, involving a load weighing approximately 790 kg, the pilot was approaching the landing site at approximately 11:45 local time when an engine failure occurred. To avoid endangering ground personnel, the pilot maneuvered the aircraft to the left to release the external load between the slopes of a shed roof. The pilot then executed a hover-autorotation onto the roof. The impact resulted in heavy damage to the aircraft and damage to the building's roof structure.

The investigation

The BFU investigation established that the pilot had been flying for approximately 55 minutes prior to the accident. During the approach, the fuel pressure warning light (FUEL P) illuminated. The pilot reported that the fuel quantity indicator showed approximately 7% remaining fuel at that moment. Notably, the fuel warning light (FUEL) had already been illuminated for approximately 15 minutes prior to the engine failure.

Upon inspection of the aircraft at the crash site, investigators found the rotor blades severely damaged and some blade holders broken. The nose of the fuselage was damaged, and the tail boom was buckled. No fuel was leaking from the aircraft at the scene. After the recovery of the helicopter, investigators drained approximately two liters of residual fuel from the tank.

Findings

  • The primary cause of the engine failure was fuel starvation.
  • The pilot was aware of a fuel warning for approximately 15 minutes before the engine failed.
  • The pilot's decision to maneuver the aircraft to release the load was intended to protect ground personnel.
  • The aircraft was operating under a special permit that allowed for the specific flight profile and low-altitude operations at the site.

Probable cause

The engine failure was caused by fuel starvation, as the pilot continued flight operations for approximately 15 minutes after the fuel warning light had initially illuminated, leaving insufficient fuel to maintain engine operation.

Frequently asked questions

What happened in the 2011-09-10 Eurocopter France AS350 B2 accident near Hannover, DE?

An Eurocopter AS350 B2 sustained heavy damage after the pilot performed an autorotative landing on a factory roof following an engine failure caused by fuel starvation.

What aircraft was involved and where did it happen?

The accident on 2011-09-10 involved a Eurocopter France AS350 B2, at Hannover, DE.

What was the probable cause of the accident?

The engine failure was caused by fuel starvation, as the pilot continued flight operations for approximately 15 minutes after the fuel warning light had initially illuminated, leaving insufficient fuel to maintain engine operation.

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