Mcdonnell Douglas Helicopter 369E incident near Allentown, Pennsylvania, September 29, 2008
On September 29, 2008 at about 3:25 pm local time, a Mcdonnell Douglas Helicopter 369E, registered N801SB, suffered minor damage in an incident during enroute (cruise) near Allentown, Pennsylvania (Queen City Airport). It was a positioning flight under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The fatigue failure of a blade in the second-stage turbine wheel, which resulted in a total loss of engine power.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 29, 2008 · about 3:25 pm local time
- Place
- Allentown, Pennsylvania · Queen City Airport · map
- Type
- Incident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Mcdonnell Douglas Helicopter 369E · all 369Es on the register
- Registration
- N801SB · registry record · serial 0209E
- Damage
- Minor damage
- Flight
- Positioning flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The helicopter experienced a total loss of engine power in flight and the pilot performed an off-airport landing in a hayfield. The pilot was uninjured and the helicopter was not damaged. Examination of the exhaust stacks revealed minor internal impact damage, consistent with high velocity objects exiting the engine. The fourth-stage turbine wheel outer ring was missing material along an approximately 30-degree arc and could not be rotated by hand. The engine had been overhauled at a facility in Canada and installed on the incident helicopter by the operator approximately 6 flight hours prior to the event. Several parts of the engine were removed and sent to the Safety Board's Material Laboratory for examination. Examination of the second-stage turbine wheel revealed a fatigue fracture through a blade. The fatigue progressed through approximately half of the airfoil, and the origin was located in the transition radius between the wheel rim outer diameter and the blade near the junction of a fore-to-aft mold line that was created during original manufacture. The blade failed due to fatigue, and the oxidation of the blade fracture surface suggested that the fatigue was due to thermal loads. No metallurgical or mechanical discontinuities were noted at the surface. Examination of the other 23 blades on the same wheel revealed small cracks in the same general location as the fatigue origin on the fracture blade. The fuel nozzle spray pattern was within specification, and there was no indication of flame streaking throughout the turbine components. Although a crack at the base of the blades on the second-stage power turbine wheel was a relatively new location, and similar failures had the same performance modifications performed, the investigation was unable to identify a connection between the performance modifications and the fatigue at the base of the blade.
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
- Loss of engine power (total) during enroute (cruise) defining event
- Autorotation Off-field or emergency landing
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine (turbine/turboprop) › Turbine section › Fatigue/wear/corrosion
Pilot
- Certificate: commercial pilot
- Ratings: rotorcraft: helicopter
- Flight time: 6,831 hours in all; 5,962 in this make and model
- Last flight review: January 24, 2008
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 1,673 hours
- Last inspection: 100-hour inspection, August 27, 2008
- Seats: 4
- Landing gear: fixed
- Engine: Rolls Royce 250-C2B (turboshaft); 0 hours total
- Operator: Haverfield International INC
The flight
- Departed from: XLL Allentown PA at 3:15 pm
- Destination: SWF Newburg NY
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 290° at 9 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 2,900 ft
- Temperature: 68°F (20°C), dew point 57°F (14°C)
- Altimeter: 29.98 inHg
- Observation at 2:51 pm from ABE, 6 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.