Accident RotorWay Exec 162F N21901,
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ASN Wikibase Occurrence # 297451
 
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Date:Monday 1 April 2002
Time:09:55 LT
Type:Silhouette image of generic EXEC model; specific model in this crash may look slightly different    
RotorWay Exec 162F
Owner/operator:Cobb International, Inc.
Registration: N21901
MSN: 6035
Total airframe hrs:1776 hours
Engine model:Rotorway 162F
Fatalities:Fatalities: 0 / Occupants: 2
Aircraft damage: Substantial
Category:Accident
Location:Chandler, Arizona -   United States of America
Phase: Unknown
Nature:Training
Departure airport:Chandler, AZ (P19)
Destination airport:
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
The helicopter collided with the ground following a loss of tail rotor drive during a steep approach. After performing various maneuvers, the certified flight instructor (CFI) and the student began traffic patterns to a landing zone (LZ). On short final, approximately 40 feet agl, and 40 mph, the helicopter yawed left slowly. When the helicopter had reached a 45-degree left yaw, the CFI took the controls. As the helicopter approached a 90-degree left yaw, the CFI had applied full right pedal. Simultaneously, he lowered the collective and reduced power. The helicopter rotated 360 degrees about 3 times before impact. Post accident inspection revealed incorrect installation of the forward end of the intermediate drive belt on the intermediate pulley group. The tail rotor drive system uses three belts, interconnected via pulleys at various points within the tail boom, to drive the tail rotor. The forward and aft belts and pulleys were normal. The intermediate belt was found shredded, burned, and separated. The aft end of the intermediate belt was positioned correctly on the rear pulley; however, the forward end was around the wrong pulley, the one meant for the forward belt, which induced a large misalignment of the intermediate belt and consequent rub between it and the pulley side. All pulleys were installed with specified tightness and with fore/aft play as stated in the maintenance manual. Maintenance records for the helicopter indicated that the belts were replaced twice in the past 8 months, both times by the manufacturer. The first time was in August 2001, for a heavy maintenance rebuild. The second time was in November 2001 following a tail rotor strike. The belts had about 200 hours operating time since their last replacement in November.

Probable Cause: The tail rotor drive system failure as a result of incorrect installation procedures by the manufacturer's personnel.

Accident investigation:
cover
  
Investigating agency: NTSB
Report number: LAX02LA121
Status: Investigation completed
Duration: 1 year and 10 months
Download report: Final report

Sources:

NTSB LAX02LA121

Revision history:

Date/timeContributorUpdates
14-Oct-2022 18:44 ASN Update Bot Added

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