Garlick OH-58A+ N802JB

Summary

On 15 July 2010 at about 17:58 local time, a Garlick OH-58A+ registered N802JB, operated by Horizon Helicopters LLC, was involved in an accident near Rowley, Massachusetts, 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

15 July 2010 at 17:58

Classification

Accident

Location

Rowley, Massachusetts, United States

Coordinates

42.7706, -70.8747

Aircraft

Garlick OH-58A+

Registration

N802JB

Category

Helicopter

Engines

1

Operator

Horizon Helicopters LLC

Operating rule

Part 137: Agricultural

Purpose of flight

Aerial Application

Phase of flight

Not recorded

Route

Newbury → Rowley

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

ERA10LA362

Nobody was injured.

The failure of the power turbine governor internal driveshaft bearings, resulting in the failure of the governor.

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

Read the full NTSB narrative

The pilot stated that he was conducting an aerial application flight when the low rotor rpm audio warning sounded. The pilot elected to fly the helicopter for another 30 minutes to ensure normal operation. Shortly thereafter, about 200 feet above ground level and at 70 knots, the low rotor rpm audio warning sounded again. The pilot lowered the collective to restore rotor rpm, but engine and rotor speed accelerated through the upper limits. The pilot then reduced the throttle to idle and performed an autorotation. The helicopter landed hard into a salt marsh, buckling the tail boom. The pilot did not report any flight control anomalies with the helicopter. A postaccident examination of the governor drive housing and driveshaft assemblies revealed that the inner and outer raceways were "frosted" in the ball tracks. Additionally, the ball tracks were offset from the center of the raceway in a manner consistent with a thrust load towards the driveshaft nut, relative to the drive housing. The ball track offset was not circumferentially uniform, suggesting that the bearing inner races were misaligned relative to the outer bearing races. In general, such misalignment typically results in excessive forces and subsequent fatigue failure of the ball separator. The failure of the drive bearings caused the power turbine governor to provide the incorrect signal to the main fuel control. A review of the engine records indicated that the last overhaul of the power turbine governor was at 1,942.9 hours time since new. The power turbine governor has accumulated an additional 1,590 hours time since overhaul. The power governor turbine time before overhaul (TBO) time is 2,000 hours.

Quoted verbatim from the NTSB record.