Accident Bell 206B-III N2773R,
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ASN Wikibase Occurrence # 360996
 
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Date:Friday 10 December 1993
Time:19:00 LT
Type:Silhouette image of generic B06 model; specific model in this crash may look slightly different    
Bell 206B-III
Owner/operator:Warren Smith
Registration: N2773R
MSN: 2772
Total airframe hrs:1005 hours
Engine model:Allison 250-C20B
Fatalities:Fatalities: 0 / Occupants: 2
Aircraft damage: Substantial
Category:Accident
Location:Flagstaff, AZ -   United States of America
Phase: En route
Nature:Private
Departure airport:
Destination airport:
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
FOLLOWING AN ANNUAL INSPECTION, THE HELICOPTER HAD EXPERIENCED AN INTERMITTENT ILLUMINATION OF THE 'ENGINE OUT' ANNUNCIATOR LIGHT. THE PILOT CONTINUED FLYING AND MONITORED THE ENGINE INSTRUMENTS, PARTICULARLY THE N2 POWER TURBINE GAUGE. DURING THE ACCIDENT FLIGHT, THE ANNUNCIATOR AGAIN FLICKERED AND THEN STAYED ON. IN ADDITION, THE 'ENGINE OUT' HORN ALSO SOUNDED; HOWEVER, THE ENGINE PARAMETERS REMAINED NORMAL. THE ANNUNCIATOR LIGHT AND HORN WILL ACTIVATE IF THE N1 GAS PRODUCER FALLS BELOW 55 PERCENT. THE PILOT REPORTED THAT DURING A TURN, THE N2 BEGAN DECREASING AND HE ENTERED AN AUTOROTATION. THE HELICOPTER ROLLED OVER FOLLOWING A HARD LANDING. POSTACCIDENT TESTS REVEALED THAT THE ENGINE OPERATED WITHIN NORMAL SPECIFICATIONS. THE N2 TACH GENERATOR OPERATED NORMAL. THE N1 TACH GENERATOR FAILED.

Probable Cause: The pilot's improper initiation of an emergency autorotation into unsuitable terrain and subsequent hard landing and rollover. A false annunciator indication, a failure of the N1 tach generator, the pilot's continued flight with a known aircraft defect, and the pilot's improper identification of the failed N1 gauge were factors in this accident.

Accident investigation:
cover
  
Investigating agency: NTSB
Report number: LAX94LA075
Status: Investigation completed
Duration: 10 months
Download report: Final report

Sources:

NTSB LAX94LA075

Location

Revision history:

Date/timeContributorUpdates
16-Mar-2024 13:41 ASN Update Bot Added

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