- Date
- October 2, 1991, 13:20 local (21:20 UTC)
- Place
- Fairbanks, AK
- Injuries
- 5 uninjured
- Damage
- Minor damage
- Phase of flight
- Enroute
- Aircraft
- N200AKPiper PA-31-350
- Weather
- Visual (VMC) · Day
- Status
- Completed · report May 5, 1993
- Report
- Approved by Office Director
- NTSB office
- Alaska Regional Office
- FAA report
- 19911002055499I
- Case key
- 5655
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the incident.
On this page
Probable cause
Incorrect installation of crankshaft counterwweight rollers by the manufacturer during remanufacture of the engine. Factor was the inadequate surveillance of the engine assembly process by the manufacturer.
Sequence of events
NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.
Analysis
During cruise flight, the left engine lost power and oil pressure. An engine teardown analysis showed that the crankshaft counterweights had two incorrect of the four installed rollers. All four rollers were part no. 73648. According to Textron Lycoming, the correct roller configuration should have been 'two part no. 73648 5.1 order and two part no. 76788 6.3 order rollers.' As configured, the engine would experience unacceptable 6th order torsional vibrations.
Aircraft
- Registration
- N200AK
- Reported as
- Piper PA-31-350
- Category
- Airplane
- Serial number
- 31-8052180
- Airframe hours
- 1,763
- Engine
- Lycoming TIO-540J2BD, 350 horsepower, reciprocating
- Damage
- Minor damage
- Fire
- In-Flight
- Flight
- Part 135
- Operator
- Frontier Flying Service Inc.
- Registered owner
- Frontier Flying Service Inc.
- Airworthiness certificate
- Standard, Utility; Standard, Normal
- Last inspection
- AAIP · September 27, 1991 · 26 hours before
- Departed
- FAI · Fairbanks, AK
- Destination
- CXF · Coldfoot, AK
- Flight plan
- VFR
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 35
- Certificates
- Private, Airline transport
- Airplane ratings
- Single-engine land, Multi-engine land, Single-engine sea
- Instrument ratings
- Airplane
- Medical
- Class 1, Valid Medical--no waivers/lim.
- Seat
- Left
- Flight hours
- 8,000 total · 6,000 in this make and model · 7,800 as pilot in command · 300 in the last 90 days · 100 in the last 30 days · 6 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Visibility
- 99 statute miles
- Lowest ceiling
- None
- Temperature
- 39 °F
- Altimeter
- 30.00 inHg
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.
Other investigations on N200AK · 1
Matched to the same aircraft by N-number and date.