Individually Owned: 150,657
Corporate Owned: 137,281
Aircraft Accident/Incident Report
Honesdale, Pennsylvania 18431
Monday, June 11, 2001 10:10 EDT
NTSB Narrative Summary Released at Completion of Accident
The sales demonstration pilot was in the right seat and the prospective buyer was in the left seat. About 1 1/2 hours after takeoff, while in cruise flight at an altitude estimated by a witness to be between 3,000 feet and 3,500 feet, an explosion occurred in the engine compartment, and white smoke began emanating from the exhaust stacks. The airplane circled down to a forced landing in an area of rolling hills, farms, and pastures bordered by stone walls embedded with trees. As the airplane was nearing the ground, a witness saw it make a sharp left turn, then impact trees and a stone wall between two pastures. Area winds at the time of the accident were calm. The airplane was equipped with an overhauled Allison (Rolls Royce Corporation) 250-B17F2 engine which had been installed 9 months, and about 25 operating hours earlier. Teardown examination of the engine after the accident revealed a tri-burst of the third stage turbine wheel, due to an overspeed of N2 after a sudden loss of load on the power train. It also revealed a failure of the torquemeter gearshaft, from a crack which initiated in an area of intergranular separation, and subsequently progressed in high cycle fatigue. The intergranular separation resulted from "stress corrosion mechanisms during the AMS 2485 black oxide treatment [process]." The torquemeter gearshaft had been installed during the engine overhaul.
NTSB Probable Cause Narrative
An improperly manufactured torquemeter gearshaft assembly, which resulted in gearshaft assembly failure, an N2 overspeed, and a subsequent uncontained engine failure.
Event Information
| Type of Event | Accident |
| Event Date | 6/11/2001 |
| Event Day of the Week | Monday |
| Time of Event | 1010 |
| Event Time Zone | Eastern Daylight Time |
| Event City | Honesdale |
| Event State | PENNSYLVANIA |
| Event Country | -- |
| Zipcode of the event site | 18431 |
| Event Date Year | 2001 |
| Event Date Month | 6 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | -- |
| Event Location Longitude | -- |
| Event Location Airport | -- |
| Event Location Nearest Airport ID | -- |
| Indicates whether the acc/inc occurred off or on an airport | Off Airport/Airstrip |
| Distance from airport in statute miles | -- |
| Degrees magnetic from airport | -- |
| Airport Elevation | -- |
| Weather Briefing Completeness | Not pertinent |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 954 Eastern Standard Time |
| Direction of event from weather observation facility (degrees) | 230 |
| Weather Observation Facility ID | AVP |
| Elevation of weather observation facility | 955 |
| Distance of event from weather observation facility (units?) | 28 |
| Time Zone of the weather observation | EST |
| Lighting Conditions | Day |
| Lowest Ceiling Height | -- |
| Lowest Non-Ceiling Height | -- |
| Sky/Lowest/Cloud Conditions | Clear |
| Sky Condition for Lowest Ceiling | None |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | 8 |
| Air Temperature at event time (in degrees celsius) | 19 |
| Dew Point at event time (in degress fahrenheit) | 15 |
| Wind Direction (degrees magnetic) | -- |
| Variable Wind Indicator | -- |
| Wind Speed (knots) | -- |
| Wind Velocity Indicator | Calm |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 29.88 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | -- |
| Event Highest Injury | Fatal |
| On Ground, Fatal Injuries | -- |
| On Ground, Minor Injuries | -- |
| On Ground, Serious Injuries | -- |
| Injury Total Fatal | 3 |
| Injury Total Minor | -- |
| Injury Total None | -- |
| Injury Total Serious | -- |
| Injury Total All | 3 |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 12436 |
| NTSB Notification Source | FAA EROC |
| NTSB Notification Date | Jun 11 2001 12:00AM |
| NTSB Notification Time | 1245 |
| Fiche Number and/or location -used to find docket information | DMS |
| Date of most recent change to record | Oct 23 2002 10:24AM |
| User who most recently changed record | NTSB\MONR |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | Allentown |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N450M |
| NTSB Number | NYC01FA141 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 91: General Aviation |
| Type of Flight Plan filed | None |
| Flight plan Was Activated? | No |
| Damage | Destroyed |
| Aircraft Fire | Ground |
| Aircraft Explosion | In-flight |
| Aircraft Manufacturer's Full Name | Cessna |
| Aircraft Model | P210N |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | P21000631 |
| Certified Max Gross Weight | 4016 |
| Aircraft Category | Airplane |
| Aircraft Registration Class | U.S. Registered/U.S. Soil |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | -- |
| Cabin Crew Seats | -- |
| Passenger Seats | -- |
| Total number of seats on the aircraft | 6 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Retractable |
| Aircraft, Type of Last Inspection | Annual |
| Date of Last Inspection | Sep 13 2000 12:00AM |
| Airframe hours since last inspection | 25 |
| Airframe Hours | 2311 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | -- |
| Aircraft Owner Name | Imperial Sales, Inc. |
| Aircraft Owner Street Address | RR 3 Box 218A |
| Aircraft Owner City | Harrington |
| Aircraft Owner State | DE |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 19952 |
| Operator is an individual? | No |
| Operator Name | O & N Aircraft Modifications, INc. |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | 210 Windsock Lane |
| Operator City | Factoryville |
| Operator State | -- |
| Operator Country | USA |
| Operator Zip code | 18419 |
| Operator Code | -- |
| Owner has at least one certificate | None |
| Other Operator of large aircraft? | -- |
| Certified for Part 133 or 137 Operation | -- |
| Operator Certificate Number | -- |
| Indicates whether an air carrier operation was scheduled or not | -- |
| Indicates Domestic or International Flight | -- |
| Operator carrying Pax/Cargo/Mail | -- |
| Type of Flying (Per_Bus / Primary) | Other Work Use |
| Second Pilot on Board | Yes |
| Departure Point Same as Event | No |
| Departure Airport Code | 9N3 |
| Departure City | Factoryville |
| Departure State | PA |
| Departure Country | USA |
| Departure Time | 845 |
| Departure Time Zone | EDT |
| Destination Same as Local Flt | dest & departure same, accident can occur anywhere |
| Destination Airport Code | -- |
| Destination City | -- |
| Destination State | -- |
| Destination Country | -- |
| Specific Phase of Flight | Maneuvering |
| Report sent to ICAO? | No |
| Evacuation occurred | No |
| Date of most recent change to record | Mar 26 2002 9:35AM |
| User who most recently changed record | PEAR |
| Since inspection or accident | Time of Accident |
| Event Location Runway Number and Location | -- |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |