Sikorsky S-76A accident near Graefenburg, Kentucky, August 7, 1992
On August 7, 1992 at about 3:10 pm local time, a Sikorsky S-76A (helicopter), registered N50KY, was destroyed in an accident near Graefenburg, Kentucky. It was a public-use flight under general aviation rules (Part 91). 5 people were seriously injured and 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
AN INADEQUATE PREFLIGHT INSPECTION BY THE FLIGHT CREW BY FAILING TO ASSURE THAT ALL FOUR OF THE ENGINE COWLING LATCHES WERE PROPERLY SECURED, WHICH RESULTED IN SUBSEQUENT FAILURE OF SECTION II OF THE TAIL ROTOR DRIVESHAFT AFTER THE COWLING CONTACTED THE MAIN ROTOR BLADES AND TAIL ROTOR DRIVESHAFT.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 7, 1992 · about 3:10 pm local time
- Place
- Graefenburg, Kentucky · map
- Type
- Accident
- Injuries
- 5 people were seriously injured and 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Sikorsky S-76A · all S-76As on the register
- Registration
- N50KY · no longer on the register · serial 760059
- Damage
- Destroyed
- Flight
- Public-use flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
BEFORE FLT, THE COPLT BGN A PREFLT INSPN, & SUBSEQUENTLY, THE HELICOPTER WAS MVD FM THE HANGAR TO THE TERMINAL, WHERE A WITNESS OBSERVED THE ENG COWLING OPEN. THE PLT ALSO MADE A WALKAROUND VISUAL INSPN OF THE HELICOPTER BFR FLT. NEITHER OF THE FLTCREW NOTED ANY DISCREPANCY. ABT 1 MIN & 40 SEC AFTER TAKEOFF, THE FLT CREW HEARD A NOISE, FLWD BY LOSS OF DRCTNL CTL; 3 OF THE PSGRS NOTED THE ODOR OF SOMETHING OVERHEATING. AN AUTOROTATION & LANDING WERE MADE ON HILLY TRRN, WHERE THE HELICOPTER CAME TO REST IN A RAVINE AGAINST A TREE. DRG AN EXAM, THE 2 LEFT SIDE ENG COWLING LATCHES WERE FND OPEN; ALSO, THE LEFT SIDE OF THE AFT ENG COWLING WAS OPEN. THERE WAS EVIDENCE THAT DURING FLT, THE LEFT SIDE OF THE COWLING CONTACTED THE MAIN ROTOR BLADES; THE COWLING THEN MADE CONTACT WITH SECTION II OF THE TAIL ROTOR DRIVESHAFT. FRICTION BTN THE COWLING & THE DRIVESHAFT RESULTED IN LOCALIZED HIGH TEMPERATURE & THE TAIL ROTOR SHAFT FAILED AT THAT LOCATION. ONE OF THE 4 TAIL ROTOR BLADES SEPARATED DURING THE OCCURRENCE.
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
Pilot
- Certificate: commercial pilot
- Ratings: instrument: helicopter; rotorcraft: helicopter
- Flight time: 6,070 hours in all; 680 in this make and model; 125 in the last 90 days; 42 in the last 30 days; 5,800 as pilot in command
- Medical certificate: Class 1 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 3,950 hours
- Last inspection: 100-hour inspection, May 29, 1992; 46 hours since
- Maximum gross weight: 10,500 lb
- Seats: 8
- Landing gear: retractable
- Engine: Allison 250-C30 (turboshaft); 0 hours total
The flight
- Departed from: FFT Frankfort KY at 3:06 pm
- Destination: FTK Ft Knox KY
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 140° at 7 knots
- Visibility: 4 statute miles
- Sky: scat at 10,000 ft
- Temperature: 72°F (22°C), dew point 66°F (19°C)
- Altimeter: 30.00 inHg
- Observation at 2:50 pm from LEX, 20 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | 1 | ||
| Passengers | 4 |
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.