Schweizer 269C N61193

Summary

On 19 March 2005 at about 21:36 local time, a Schweizer 269C registered N61193 was involved in an accident near Leet, West Virginia, United States. 2 people were on board and one was seriously injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

19 March 2005 at 21:36

Classification

Accident

Location

Leet, West Virginia, United States

Coordinates

38.0519, -81.9869

Aircraft

Schweizer 269C

Registration

N61193

Category

Helicopter

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

S. Charleston → Logan

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

IAD05LA046

1 person was seriously injured.

A fatigue fracture of the main transmission drive pinion. Also causal was the manufacturer's failure to remove the affected pinions from service during the period that transpired between the initial failures and the accident flight.

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

Read the full NTSB narrative

While investigating a fire, the pilot noticed an "unusual vibration," and a "needle split" on the rpm gauge. The rotor speed began to decay and the engine speed began to increase. The pilot then entered an autorotation. The helicopter, impacted terrain, was substantially damaged, and a passenger was seriously injured. Examination of the drive train revealed that the main drive pinion, which drove both the main rotor assembly and the tail rotor drive shaft, had failed in fatigue that had initiated in the root of the first (most forward) engaged pinion thread. The failed pinion had been in service for 4,055.4 hours. Including the accident pinion, 10 instances of pinion failures were identified during the investigation. Times in service ranged from 261.5 to 4,243 hours. According to the manufacturer, life limits for the pinion ranged from 6,000 to 8,000 hours depending on application. As a result of this investigation, The FAA issued an SAIB alerting owners and operators of pending revisions to the inspection procedures for the pinion. The manufacturer revised its Handbook of Maintenance Instructions, to include the revised inspection procedures, and submitted design revisions to the FAA to make the part more robust.

Quoted verbatim from the NTSB record.