Casualties unknown

1999-02-09: Hughes 369D (N5070J) — Agrotors Inc. — Herminie, PA

Herminie, PA, US

On February 9, 1999, a Hughes 369D (registration N5070J) operated by Agrotors Inc. was involved in an aviation accident near Herminie, PA. Investigators recorded the probable cause as: The partial loss of engine power for undetermined reasons. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 1 related events involving the same aircraft type or operator are linked below.

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

A helicopter experienced an engine power loss warning while hovering near a powerline tower, leading to a hard landing. Post-incident testing found no discrepancies and the power output exceeded rated levels.

Incident Details

A helicopter was positioning next to a powerline tower while in an out of ground effect hover. During the hover, the engine out warning horn sounded, alerting the pilot of a possible power loss. The pilot backed the helicopter away from the tower, lowered the collective, and turned to the left to avoid the tower. Approximately 10–15 feet above the ground, the engine lost additional power, causing the helicopter to descend rapidly. Just prior to impact, the pilot applied maximum collective, and the helicopter landed hard. After landing, the pilot shut down the engine.

Post-Incident Investigation

The engine was removed and accelerated in a test cell from 70 percent to 95 percent torque. No discrepancies were noted, and power calibrations were computed. The computed power calibrations revealed that the engine was producing 12 percent more than rated power. The fuel control unit was removed from the engine, inspected, and tested. No conditions were found that would have prohibited the unit from operating normally at the time of the incident.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001205X00229. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.