Sikorsky S-58HT accident near Belmont, West Virginia, March 9, 2008
On March 9, 2008 at about 6:40 pm local time, a Sikorsky S-58HT (helicopter), registered N1078T, was substantially damaged in an accident during maneuvering near Belmont, West 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 fatigue failure of a tail rotor blade during an external load lift.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- March 9, 2008 · about 6:40 pm local time
- Place
- Belmont, West Virginia · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Sikorsky S-58HT · all S-58HTs on the register
- Registration
- N1078T · no longer on the register · serial 58-1016
- Damage
- Substantial damage
- Flight
- External-load flight · external-load helicopter rules (Part 133)
The NTSB's narrative final · quoted from the NTSB record
The helicopter was performing external load operations, and was removing a tower from the top of a 620-foot tall smoke stack. After lifting the load clear of the smoke stack, the pilot observed an "over torque" condition on the torque indicator. Several seconds later, the pilot felt a high frequency vibration through the helicopter, and shortly thereafter the tail rotor assembly separated from the helicopter. While the helicopter yawed through two 360-degree rotations, the pilot released the external load, reduced the collective pitch, and performed an autorotation. Postaccident examination of the separated tail rotor assembly revealed that one of the four blades had separated in-flight. Detailed examination of the separated blade revealed that its skins had cracked due to fatigue, and that the blade then separated due to overstress. The adjacent and overlaying doublers also cracked, likely due to fatigue, but no fatigue striations were found on those members. Some ductile dimples were also found in the damaged regions, indicating that at least part of the propagation was by unstable crack growth. The skin fatigue cracks were completely hidden by the overlying doublers, making detection impossible unless the doublers either cracked or were removed. Cracks in the doublers would have been visible on the inboard side of the blade, but not on the outboard side, where the inspection/repair tag covered most of the doubler. The bonds within the blade appeared to be in good condition, and no corrosion was found, suggesting that the blade failure was the result of a fatigue life issue. The helicopter’s maintenance manual specified that the tail rotor blades had no life limit, provided that certain flight restrictions were observed, but the investigation was unable to determine whether the helicopter ever exceeded any of the specified flight restrictions. None of the tail rotor blades were in compliance with an existing airworthiness directive, which required the installation of an abrasion strip along the entire length of the blade leading edge; however, it was not clear if this non-compliance affected the failure.
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
- Flight control sys malf/fail during maneuvering defining event
- Loss of control in flight during maneuvering
- Collision with terrain or object (not controlled flight into terrain) during emergency descent
The NTSB's findings
- cause Aircraft › Aircraft propeller/rotor › Tail rotor › Tail rotor blade › Fatigue/wear/corrosion
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane single-engine; instructor: helicopter; instructor: instrument helicopter; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 12,000 hours in all; 18,000 in this make and model; 120 in the last 90 days; 46 in the last 30 days; 11,700 as pilot in command; 3,000 on instruments
- Last flight review: March 15, 2007
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: rgt
- Injury: serious injuries
The aircraft
- Airframe total time: 18,397 hours
- Last inspection: continuous airworthiness programme, December 20, 2007
- Maximum gross weight: 13,000 lb
- Seats: 4
- Landing gear: fixed
- Engine 1: Pratt And Whitney Canada PT-6T3 (turboshaft); 0 hours total
- Engine 2: PT-6T3 (turboshaft); 0 hours total
- Operator: St. Louis Helicopters LLC
The flight
- Departed from: PKB Parkersburg WV
- Destination: PKB
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 200° at 5 knots
- Visibility: 10 statute miles
- Sky: a few clouds at 3,600 ft
- Temperature: 30°F (-1°C), dew point 19°F (-7°C)
- Altimeter: 30.37 inHg
- Observation at 6:53 pm from PKB, 7 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.