Bell 206 N64AW

Summary

On 12 September 2014 at about 18:15 local time, a Bell 206 registered N64AW, operated by Airwest Helicopters LLC, was involved in an accident near Tombstone, Arizona, United States. 2 people were on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

12 September 2014 at 18:15

Classification

Accident

Location

Tombstone, Arizona, United States

Coordinates

31.7014, -110.0536

Aircraft

Bell 206

Registration

N64AW

Category

Helicopter

Year built

2004

Engines

1

Operator

Airwest Helicopters LLC

Operating rule

Part 135: Air Taxi & Commuter

Phase of flight

Not recorded

Route

Sierra Vista → Sierra Vista

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR14LA374

Nobody was injured.

A partial loss of engine power during cruise flight due to loose “B” nut fittings and a bent tube as a result of maintenance personnel’s inadequate inspection of the nuts during the most recent inspection.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

The commercial pilot reported that, after initiating a climb for the local flight, he observed that the helicopter was not producing adequate power. He found a suitable landing site and descended toward it. When the helicopter was about 60 to 70 ft above the ground, the helicopter started descending rapidly and impacted the ground hard. During a pressure leak check of the engine, air leaks at three separate "B" nut fittings were found; two of the leaks were at the power turbine governor, and one leak was at the gas producer fuel control. The engine was test run, and it operated; however, it then lost power consistent with the pilot's report. Further examination of the "B" nut fittings revealed that one of the "B" nuts was less than finger tight, the second one was just above finger tight, and the third exhibited breakaway torque within the specified range. The "B" nut fittings were tightened to specifications and rechecked. One of the leaks was still present; the tube was removed, and it was bent near where the leak was found. A new tube was installed, and the engine was run again with no anomalies noted. The engine manufacturer had previously issued several commercial service letters regarding the importance of properly torqueing and aligning the fuel, lubrication, and pneumatic systems tubes and fittings; the service letters contained proper directions, placards, and 100-hour-inspection requirements. The helicopter's most recent 100-hour inspection occurred about 66 hours before the accident. It is likely that the "B" nuts became loose during the approximate 66 hours of operation since the most recent inspection and that maintenance personnel did not adequately inspect the "B" nuts at that inspection and, thus, failed to detect that they were not properly torqued. It could not be determined when the tube became bent.

Quoted verbatim from the NTSB record.