Casualties unknown

1985-06-07: Hughes 369HS (N9146F) — Aiken, SC

Aiken, SC, US

On June 7, 1985, a Hughes 369HS (registration N9146F) was involved in an aviation accident near Aiken, SC. Investigators recorded the probable cause as: The loss of engine power was due to fuel exhaustion resulting from a collapsed fuel cell (caused by missing support brackets) that produced erroneous fuel quantity indications, and an inoperative low fuel caution indicator due to an improperly wired cannon… 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

During landing, engine lost power, leading to a hard touchdown. Missing support brackets caused fuel cell collapse and erroneous fuel gauge readings; low fuel caution indicator was inoperative.

Incident Overview

A helicopter experienced a loss of engine power during a landing approach, resulting in a hard touchdown. The pilot reported that prior to the 15-minute flight, the fuel gauge indicated 125 pounds of fuel, and at the accident site, it indicated 90 pounds.

Post-Crash Inspection Findings

A post-crash inspection of the fuel system revealed that three support brackets were not installed in the fuel cell. The absence of these brackets permitted the fuel cell to collapse as fuel was consumed, leading to erroneous fuel gauge readings. Furthermore, the fuel low caution indicator was found to be inoperative because a cannon plug was improperly wired. Only a trace of fuel remained in the tank after the incident.

Fuel System Condition

The malfunctioning fuel gauge and inoperative low-fuel warning system together prevented the pilot from accurately assessing the remaining fuel quantity. The collapsed fuel cell likely caused the gauge to indicate a higher fuel level than actually present, leading to fuel exhaustion during the flight.

Sequence of Events

According to the pilot's statement, the flight duration was approximately 15 minutes. The engine power loss occurred as the helicopter was landing. The hard touchdown followed the loss of power. No further details about the aircraft or occupants were provided in the source.

Probable cause

The loss of engine power was due to fuel exhaustion resulting from a collapsed fuel cell (caused by missing support brackets) that produced erroneous fuel quantity indications, and an inoperative low fuel caution indicator due to an improperly wired cannon plug.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001214X36664. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.