Rotorway 162F N176BT

Summary

On 31 May 1997 at about 14:05 local time, a Rotorway 162F registered N176BT was involved in an accident near Phoenix, Arizona, United States. One person was on board and one died. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

31 May 1997 at 14:05

Classification

Accident

Location

Phoenix, Arizona, United States

Nearest airport

Phoenix-Deer Valley Muni (DVT)

Coordinates

33.6804, -112.0901

Aircraft

Rotorway 162F

Registration

N176BT

Category

Helicopter

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Aircraft damage

Destroyed

Weather

VMC

Light

Day

NTSB number

LAX97LA197

1 person died.

the owner/builder incorrectly installed the tail rotor drive pulley mounting scissors, overtorqued the pivot belts, did not perform the required maintenance lubrication of the pivot belts, and failed to perform adequate visual maintenance checks of these areas during the pre/postflight checks; the resultant overtemperature on the pulley idlers; eventual catastrophic failure of the drive belts; and the pilot's failure to maintain rotor rpm during autorotation, which resulted in loss of aircraft control and subsequent collision with the terrain.

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

Read the full NTSB narrative

While inbound to an airport, the pilot transmitted 'mayday' twice, but did not state the nature of the emergency. Witnesses saw the helicopter spin 4 to 5 revolutions, then it stopped spinning & fell to the ground. Reportedly, the rotors stopped turning before ground impact. Exam of the helicopter revealed the pivot bolts & brackets for the tail rotor drive assemblies had been overtorqued, & the pivot belts had no lubrication on the bolts or associated surfaces. The tail rotor drive belt was found frayed & shredded. Both idler pulleys & their associated mountings had not been constructed or installed correctly. A tail rotor belt advisory bulletin from Rotorway advised that temperature strips be installed on the 2 tail rotor idler pulleys & the drive pulley. It required an exam of the temperature strips before & after each flight, & it cautioned that if the 170-degree dot darkened, that was an indication that a belt may be slipping or some other problem existed; & if the 180-degree dot darkened, the belts had been damaged from heat & must be replaced. Temperature dots on this helicopter indicated the temperature had exceeded 200 degrees. The owner/builder was instructed to visually check the travel of the idler pulley swing arm, condition of the drive belts, condition of the pulleys & bearings, & temperature strips during preflight inspection. Visual inspection revealed no evidence that the inspection door had ever been opened, since the original paint seal had never been broken.

Quoted verbatim from the NTSB record.