Hughes 369D accident near Greenville, Virginia, June 2, 2009
On June 2, 2009 at about 3:10 pm local time, a Hughes 369D (helicopter), registered N8356F, was substantially damaged in an accident during maneuvering (low-alt flying) near Greenville, Virginia. It was an external-load flight under external-load helicopter rules (Part 133). 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The inadequate design of the fourth-stage turbine wheel, resulting in the fatigue failure of one airfoil and a subsequent 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
- June 2, 2009 · about 3:10 pm local time
- Place
- Greenville, Virginia · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Hughes 369D · all 369Ds on the register
- Registration
- N8356F · registry record · serial 1260063D
- Damage
- Substantial damage
- Flight
- External-load flight · external-load helicopter rules (Part 133)
The NTSB's narrative final · quoted from the NTSB record
Following completion of aerial tree cutting near power lines, the pilot returned to the designated landing zone and, while maneuvering for landing after placing the saw on the ground, the engine experienced a loss of power. The pilot attempted to perform an autorotative landing but landed hard, causing substantial damage to the helicopter. Postaccident inspection of the engine revealed one airfoil of the fourth-stage power turbine wheel fractured near the hub due to high-cycle fatigue that initiated on the pressure side of the airfoil at the trailing edge. No surface defects were noted along the root filet radius adjacent to the fracture initiation region. The enhanced fourth-stage power turbine wheel was manufactured in October 2006, installed into the turbine assembly, operated for 1,769 hours, then removed for a 1,750-hour inspection. The fourth-stage power turbine wheel remained installed in the turbine assembly at the completion of the inspection, and the turbine assembly was reinstalled onto the engine. At the time of failure, the wheel had accumulated approximately 2,690 hours since new and approximately 921 hours since the last 1,750-hour inspection was performed. Since 2005, there have been four other fatigue failures of an airfoil of an enhanced fourth-stage turbine wheel. All other failures initiated at the trailing edge near the hub. In December 2006, Rolls-Royce developed an engine alert bulletin (CEB-A-1400) alerting owners and operators of the accident make and model engine to avoid steady state N2 speed between 75 to 88 percent above 85 shaft horsepower (shp). Additionally, Rolls-Royce reported that their research of failures of airfoils of the fourth stage power turbine revealed the possibility of a higher stress state in the airfoil at the trailing edge root than originally modeled. The stress, which occurs during engine start, results from thermal differentials in the airfoil geometry that produce a residual stress at the trailing edge root that can lead to a fatigue crack. Once a crack occurs, it can propagate in high-cycle fatigue followed by overload failure if the engine is operated in a steady state in the N2 speed avoidance range (75 to 88 percent N2) above 85 shp, as specified in CEB-A-1400.
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 maneuvering (low-alt flying) defining event
- Hard landing during landing (flare/touchdown)
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine (turbine/turboprop) › Turbine section › Design
- Aircraft › Aircraft power plant › Engine (turbine/turboprop) › Turbine section › Failure
Pilot
- Certificate: commercial pilot
- Ratings: rotorcraft: helicopter
- Flight time: 8,676 hours in all; 7,780 in this make and model; 105 in the last 90 days; 32 in the last 30 days; 8,610 as pilot in command
- Last flight review: April 28, 2009
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: left
- Injury: serious injuries
The aircraft
- Airframe total time: 10,518 hours
- Last inspection: 100-hour inspection, May 12, 2009
- Maximum gross weight: 3,550 lb
- Seats: 2
- Landing gear: fixed
- Engine: Allison 250-C20B (turboshaft); 0 hours total
- Operator: Aerial Solutions, Inc.
The flight
- Departed from: Greenville VA at 2:15 pm
- Destination: Greenville VA
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 190° at 7 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 84°F (29°C), dew point 70°F (21°C)
- Altimeter: 30.07 inHg
- Observation at 3:20 pm from SHD
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.
Other NTSB records under N8356F the same tail number, which may have belonged to a different aircraft at the time
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.