- Date
- August 18, 1992, 05:58 local (09:58 UTC)
- Place
- Philadelphia, PA
- Injuries
- 2 uninjured
- Damage
- Substantial damage
- Phase of flight
- Enroute
- Aircraft
- N66LAMitsubishi MU-2-60
- Weather
- Visual (VMC) · Night/dark
- Status
- Completed · report May 26, 1993
- Report
- Approved by Office Director
- FAA report
- 19920818035699A
- Case key
- 37209
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
The in-flight separation of a propeller blade as a result of fatigue cracking initiated from multiple sites located at corrosion pits in the balancing hole. Contributing factors in the accident were: the failure to detect the corrosion during the last overhaul procedure; and a complete loss of electrical power as result of the separated blade breaking the electrical lines.
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
At 6000 feet MSL, while in cruise flight, a propeller blade from the left propeller assembly separated in-flight, penetrated the fuselage, breaking electrical lines and causing a loss of electrical power. At the time the airplane was in IMC, so the pilot elected to turn 180 degrees in an attempt to fly to an area of better weather. He flew without electrical power or most of the instruments for about 40 minutes, until reaching an area of clear weather. Once the pilot was able to identify his location he elected to make a gear up landing at the nearest airport. Metallurgical examination of the separated blade revealed that the separation of the blade was the result of fatigue cracking that initiated from multiple sites located at corrosion pits in the balancing hole. It was determined that the corrosion pitting had not been detected during the last overhaul and procedures to shot peen and paint the balancing hole were not performed.
Aircraft
- Registration
- N66LA
- Reported as
- Mitsubishi MU-2-60
- Category
- Airplane
- Serial number
- 792SA
- Airframe hours
- 4,018
- Engine
- Garrett TPE331-10-511, 1,000 horsepower, turbo prop
- Damage
- Substantial damage
- Flight
- Part 135
- Operator
- Epps Air Service
- Registered owner
- Epps Air Service
- Airworthiness certificate
- Standard, Normal
- Last inspection
- AAIP · August 10, 1992 · 90 hours before
- Departed
- TEB · Teterboro, NJ
- Destination
- BKL · Cleveland, OH
- Flight plan
- IFR
- Airport
- PNE · Northeast Philadelphia, runway 6, 7,000 × 150 ft, asphalt
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 47
- Certificate
- Airline transport
- Airplane ratings
- Single-engine land, Multi-engine land
- Instrument ratings
- Airplane, Helicopter
- Medical
- Class 2, Valid Medical--no waivers/lim.
- Seat
- Left
- Flight hours
- 17,883 total · 2,900 in this make and model · 15,000 as pilot in command · 209 in the last 90 days · 68 in the last 30 days · 4 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Night/dark
- Wind
- 360° at 4 knots
- Visibility
- 5 statute miles
- Lowest ceiling
- 1,400 ft overcast
- Temperature
- 64 °F, dew point 64 °F
- Altimeter
- 30.00 inHg
- Observed at
- PNE, 1 nm away
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.