Engine Failure Leads to Fatal Kaman K-1200 Crash Near Hindelang

Casualties unknown • nahe Hindelang, DE

A Kaman K-1200 helicopter crashed near Hindelang, Germany, following a sudden engine failure during external load operations, resulting in the death of the pilot.

What happened

On September 4, 1998, a Kaman K-1200 helicopter was engaged in external load operations near Hindelang, Germany. The mission involved transporting logs from a remote forested area to a valley loading site using a 50-meter long load cable. The flight operations were being conducted in a hover to pick up and release timber.

During the pickup of a load consisting of two logs, the engine experienced a sudden loss of power. The aircraft immediately entered a steep descent. The pilot was unable to perform a successful autorotation due to the terrain, which was unsuitable for an emergency landing. The helicopter struck the ground in a nearly inverted position in a bog area approximately 15 and meters below the pickup site. The impact resulted in one fatality (the pilot) and the total destruction of the aircraft. The external load was not released prior to impact.

The investigation

The BFU investigation focused on the mechanical failure of the engine and the circumstances surrounding the crash. Investigators examined the engine's fuel control unit and the dual-segment fuel pump. The investigation also looked into the cockpit configuration, specifically the lack of pressure monitoring for the pump segments and the pilot's ability to release the cargo hook. Additionally, the physical evidence of the wreckage, including the broken rotor blades and the position of the aircraft upon impact, was analyzed to determine the sequence of events.

Findings

  • The primary cause of the accident was a sudden engine failure caused by the simultaneous failure of both drive shafts in the dual-segment, engine-driven fuel pump due to wear at two tapered shaft connections.
  • The accident was unavoidable because the helicopter was in a stationary hover over terrain that did not allow for a safe autorotative landing.
  • The Kaman K-1200 lacked a pressure monitoring system for the two pump segments, which would have allowed the pilot to detect a failure in one segment before it led to total engine power loss.
  • The failure to release the external load contributed significantly to the severity of the crash, as the weight and momentum of the logs caused the aircraft to strike the ground in a nearly inverted position.
  • The pilot's seat and restraint system were found to be inadequate for protecting the occupant during an impact in a non-normal flight attitude.

Probable cause

The engine failure was caused by the wear-induced failure of both drive shafts within the redundant fuel pump system, occurring while the aircraft was in a hover over terrain unsuitable for an emergency landing.

Frequently asked questions

What happened in the 1998-09-04 Kaman K-1200 accident near nahe Hindelang, DE?

A Kaman K-1200 helicopter crashed near Hindelang, Germany, following a sudden engine failure during external load operations, resulting in the death of the pilot.

What aircraft was involved and where did it happen?

The accident on 1998-09-04 involved a Kaman K-1200, at nahe Hindelang, DE.

What was the probable cause of the accident?

The engine failure was caused by the wear-induced failure of both drive shafts within the redundant fuel pump system, occurring while the aircraft was in a hover over terrain unsuitable for an emergency landing.

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