Robinson R22 N259TW

Summary

On 22 March 2011 at about 17:15 local time, a Robinson R22 registered N259TW was involved in an accident near Goshen, New York, 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

22 March 2011 at 17:15

Classification

Accident

Location

Goshen, New York, United States

Coordinates

40.5058, -74.2586

Aircraft

Robinson R22

Registration

N259TW

Category

Helicopter

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Hamptonburgh → West Milford

Aircraft damage

Substantial

Weather

VMC

Light

Dawn

NTSB number

ERA11LA204

Nobody was injured.

The pilot’s failure to adhere to published preflight checklist limitations and procedures, resulting in excessive slack and subsequent failure of the power transmission belts and a total loss of rotor system drive.

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

Read the full NTSB narrative

According to the pilot, following clutch engagement after engine start and warm up, it took 20 to 25 seconds for the main rotor to start turning. About 15 minutes into the flight and while cruising at 700 feet above ground level, the pilot heard a “flapping” noise and smelled burning rubber. He then “sensed” that the engine was losing power, observed numerous caution lights illuminate, and entered an autorotation. The helicopter subsequently impacted uneven terrain, which resulted in damage to the fuselage, as well as the main and tail rotor blades. Postaccident examination found that both power transmission belts had been ripped, mostly through the center of the backing, separating the two sides of the belt. A review of maintenance records showed that an airframe overhaul was completed about 4 months before the accident, which included replacement of both v-belts.According to the manufacturer’s maintenance manual, a delay of more than 5 seconds between clutch switch engagement and rotor turning indicates excessive belt slack. Power transmission belts that are too loose can jump out of their grooves during start up and jump forward into the next groove or off the forward edge of the pulley. The pre-engine start checklist instructs pilots to adjust the slack of the power transmission belt system so that the rotor begins turning within 5 seconds of clutch engagement. Evidence suggests that the pilot did not perform the recommended check.

Quoted verbatim from the NTSB record.