Casualties unknown

1982-03-18: Bell 47J-2A (N8565F) — Sky King Airways, Inc. — Emmaus, PA

Emmaus, PA, US

On March 18, 1982, a Bell 47J-2A (registration N8565F) operated by Sky King Airways, Inc. was involved in an aviation accident near Emmaus, PA. Investigators recorded the probable cause as: A sudden and complete loss of engine power during low-altitude maneuvering, which could not be explained by the subsequent engine teardown examination. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards

A helicopter experienced a sudden complete power failure while maneuvering at low altitude for an aerial photography mission. The pilot executed autorotation procedures and landed in a field with an upslope, resulting in a hard landing.

What happened

The incident occurred while the aircraft was engaged in an aerial photography mission. At the time of the event, the helicopter was maneuvering at an approximate altitude of 200 feet above ground level (AGL). During this phase of flight, the pilot experienced a sudden and complete loss of engine power.

Upon detecting the failure, the pilot immediately initiated standard autorotation procedures to maintain rotor RPM and control. The pilot directed the aircraft toward the nearest suitable landing area, which was identified as a small field located downwind. This field presented a challenge due to its terrain, featuring a 15-degree upslope. The pilot performed a flare maneuver in preparation for touchdown. Despite the controlled descent, the helicopter impacted the ground with significant force, resulting in a hard landing.

The investigation

Following the accident, investigators conducted a thorough examination of the aircraft's propulsion system to determine the root cause of the power loss. A detailed engine teardown was performed to inspect internal components for mechanical failure, wear, or damage that could explain the sudden cessation of power.

The examination results did not reveal any mechanical defects or anomalies within the engine that would account for the in-flight power failure. The lack of physical evidence suggesting a mechanical malfunction leaves the specific cause of the initial power loss undetermined based on the available forensic data.

Findings

The investigation highlighted several critical factors associated with the event:

  • Loss of power occurred suddenly during low-altitude maneuvering for aerial photography.
  • The pilot successfully executed autorotation procedures to manage the descent.
  • The landing site was a small field with a significant 15-degree upslope, complicating the touchdown.
  • The aircraft sustained damage due to the hard landing impact.
  • Engine teardown analysis found no mechanical explanation for the power failure.

Probable cause

A sudden and complete loss of engine power during low-altitude maneuvering, which could not be explained by the subsequent engine teardown examination.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20020917X02513. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.