Mitsubishi MU-2-60 accident near Philadelphia, Pennsylvania, August 18, 1992
On August 18, 1992 at about 9:58 am local time, a Mitsubishi MU-2-60, registered N66LA, was substantially damaged in an accident near Philadelphia, Pennsylvania (Northeast Philadelphia airport). It was a flight of an unrecorded kind under charter and air-taxi rules (Part 135). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
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.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 18, 1992 · about 9:58 am local time
- Place
- Philadelphia, Pennsylvania · Northeast Philadelphia · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Mitsubishi MU-2-60 · all MU-2-60s on the register
- Registration
- N66LA · registry record · serial 792SA
- Damage
- Substantial damage
- Flight
- Flight of an unrecorded kind · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- AIRFRAME/COMPONENT/SYSTEM FAILURE/MALFUNCTION during cruise - normal
- FORCED LANDING during descent - emergency
- GEAR NOT EXTENDED during landing - flare/touchdown
Pilot
- Ratings: multi-engine land, single-engine land, none, APLN, helicopter, gyroplane, helicopter
- Flight time: 17,883 hours in all; 2,900 in this make and model; 209 in the last 90 days; 68 in the last 30 days; 15,000 as pilot in command
- Medical certificate: class 2
The aircraft
- Airframe total time: 4,018 hours
- Last inspection: approved inspection programme, August 10, 1992; 90 hours since
- Maximum gross weight: 11,575 lb
- Seats: 3
- Landing gear: retractable
- Engine: Garrett TPE331-10-511 (turboprop); 0 hours total
- Operator: Epps Air Service
- Operating certificate: in the vicinity
The flight
- Departed from: TEB Teterboro NJ at 9:02 am
- Destination: BKL Cleveland OH
- Flight plan: IFR
- Runway 6, 7,000 ft by 150 ft
Weather at the time
- Light: night, dark
- Wind: from 360° at 4 knots
- Visibility: 5 statute miles
- Sky: overcast at 1,400 ft; not recorded
- Temperature: 64°C, dew point 64°C
- Altimeter: 30 inHg
- Observation at 9:50 am from PNE, 1 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 1 |
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The docket at the NTSB holds the report as a PDF and the investigation's photographs and documents. This site never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number NYC92LA166.