Accident MBB BK 117A-1 N117M,
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ASN Wikibase Occurrence # 367461
 
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Date:Tuesday 30 January 1990
Time:14:10 LT
Type:Silhouette image of generic BK17 model; specific model in this crash may look slightly different    
MBB BK 117A-1
Owner/operator:Omni Flight Helicopters, Inc.
Registration: N117M
MSN: S-7023
Total airframe hrs:3397 hours
Engine model:LYCOMING LTS-101-650B1
Fatalities:Fatalities: 0 / Occupants: 2
Aircraft damage: Substantial
Category:Accident
Location:Janesville, WI -   United States of America
Phase: En route
Nature:Unknown
Departure airport:Janesville, WI (KJVL)
Destination airport:
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
THE PILOT STATED THAT HE AND A COMPANY MECHANIC WERE IN CRUISE FLIGHT AT 2,000 FEET MSL ON A MAINTENANCE FLIGHT TEST, WHEN HE HEARD A NOISE, 'OBSERVED DEBRIS IN ALL DIRECTIONS FROM THE MAIN ROTOR...(AND) SEVERE VIBRATION WAS EXPERIENCED.' THE PILOT MADE AN EMERGENCY LANDING IN A SNOW-COVERED FIELD. POST-ACCIDENT EXAMINATION REVEALED THAT THE ENGINE COWLING ON THE LEFT SIDE OF THE AIRCRAFT HAD SEPARATED WHILE IN FLIGHT, CONTACTING AND DAMAGING THE MAIN ROTOR BLADES. SEVERAL PIECES OF THE SEPERATED COWLING WERE RECOVERED AND INSPECTED. THE LATCHES SHOWED NO MALFORMATION/STRETCHING, AND APPEARED TO BE CAPABLE OF NORMAL OPERATION.

Probable Cause: THE PILOT-IN-COMMAND FAILED TO ENSURE THAT THE ENGINE COWLING LATCHES WERE PROPERLY SECURED PRIOR TO DEPARTING ON THE MAINTENANCE TEST FLIGHT; THE COWLING CAME LOOSE DURING FLIGHT, AND CONTACTED THE MAIN ROTOR BLADES BEFORE IT SEPARATED FROM THE HELICOPTER.

Accident investigation:
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Investigating agency: NTSB
Report number: CHI90LA074
Status: Investigation completed
Duration: 2 years and 11 months
Download report: Final report

Sources:

NTSB CHI90LA074

Location

Revision history:

Date/timeContributorUpdates
22-Mar-2024 14:41 ASN Update Bot Added

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