Casualties unknown

2002-04-11: Bell 206B (N513FD) — Sky One Helicopters — Walnut Hill, TX

Walnut Hill, TX, US

On April 11, 2002, a Bell 206B (registration N513FD) operated by Sky One Helicopters was involved in an aviation accident near Walnut Hill, TX. Investigators recorded the probable cause as: The loss of engine power as a result of the backing off of the PC air line "B" nut due to the improper installation by the company maintenance personnel. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 8 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 lost power at about 400 feet AGL, executed an autorotation to a residential street, struck overhanging trees, and landed hard. Investigation found a loose B-nut on the PC pneumatic line and missing torque striping on engine B-nuts.

Incident Overview

During cruise flight at approximately 400 feet above ground level, the helicopter experienced a sudden loss of power. The pilot initiated an autorotation to a residential street. During the forced landing, the main rotor blades struck trees that overhung the street. Subsequently, the helicopter touched down hard and slid to a stop.

Examination Findings

An examination of the helicopter revealed that the B-nut on the PC pneumatic line from the power turbine governor tee fitting to the fuel control, at the fuel control end, was backed off from the fitting. When viewed initially, the B-nut appeared to be connected, but when moved by hand, it dislodged from the fuel control connection. Further examination revealed the whole engine was void of the required torque striping on all B-nuts.

Maintenance Records

Examination of the maintenance records revealed the helicopter accumulated 42.6 hours since the last 100-hour maintenance inspection that was performed on March 29, 2002.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20020412X00503. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.