Accident de Havilland Canada DHC-6 Twin Otter 100 N121PM,
ASN logo
ASN Wikibase Occurrence # 365866
 
This information is added by users of ASN. Neither ASN nor the Flight Safety Foundation are responsible for the completeness or correctness of this information. If you feel this information is incomplete or incorrect, you can submit corrected information.

Date:Sunday 9 December 1990
Time:15:00 LT
Type:Silhouette image of generic DHC6 model; specific model in this crash may look slightly different    
de Havilland Canada DHC-6 Twin Otter 100
Owner/operator:One Papa Mike Corp.
Registration: N121PM
MSN: 14
Year of manufacture:1966
Total airframe hrs:45332 hours
Engine model:P&W PT6-20
Fatalities:Fatalities: 0 / Occupants: 21
Aircraft damage: Substantial
Category:Accident
Location:Perris Valley, CA -   United States of America
Phase: Initial climb
Nature:Unknown
Departure airport:
Destination airport:
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
AFTER LIFT-OFF, AT ABOUT 100 FT AGL AND 85 KTS, THE LEFT ENG DECELERATED AND THE AIRPLANE BEGAN TO YAW AND ROLL LEFT. THE PIC ABORTED THE TAKEOFF, TURNED LEFT AND LANDED ON A FLAT LEVEL FIELD. THE AIRPLANE STRUCK A FENCE, THEN TREES. EXAMINATION OF THE LEFT ENG REVEALED THE LOSS OF POWER WAS ATTRIBUTED TO A FATIGUE FRACTURE OF A COMPRESSOR TURBINE BLADE, WHICH LED TO SUBSEQUENT BLADE FRACTURES. THE RIGHT ENG WAS EXAMINED AND FOUND TO HAVE ADVANCE WEAR ON THE THROTTLE CAM ASSEMBLY OF THE POWER TURBINE GOVERNOR. IN A TEST CELL, ONLY APRX 28% OF TAKEOFF POWER COULD BE ACHIEVED. THE CAM LOBE WEAR HAD PROGRESSED OVER AN EXTENDED PERIOD OF TIME. THE RIGHT ENGINE PROP GOVERNOR WAS REPLACED 11/18/90, FOLLOWED BY A TEST RUN.

Probable Cause: A LOSS OF POWER ON THE LEFT ENGINE DUE TO A FATIGUE FAILURE OF A COMPRESSOR TURBINE BLADE LEADING TO FURTHER COMPRESSOR BLADE DAMAGE; A WORN POWER TURBINE GOVERNOR THROTTLE CAM ASSEMBLY WHICH LED TO LOSS OF POWER ON THE RIGHT ENGINE; AND INADEQUATE MAINTENANCE AND INSPECTION BY THE OPERATOR.

Accident investigation:
cover
  
Investigating agency: NTSB
Report number: LAX91FA052
Status: Investigation completed
Duration: 2 years and 8 months
Download report: Final report

Sources:

NTSB LAX91FA052

History of this aircraft

Other occurrences involving this aircraft
6 March 1970 N121PM Pilgrim Airlines 0 Windsor Locks, CT sub

Revision history:

Date/timeContributorUpdates
20-Mar-2024 14:49 ASN Update Bot Added

Corrections or additions? ... Edit this accident description

The Aviation Safety Network is an exclusive service provided by:
Quick Links:

CONNECT WITH US: FSF on social media FSF Facebook FSF Twitter FSF Youtube FSF LinkedIn FSF Instagram

©2024 Flight Safety Foundation

1920 Ballenger Av, 4th Fl.
Alexandria, Virginia 22314
www.FlightSafety.org