Bell 47G2 accident near Ardmore, Oklahoma, March 22, 2001
On March 22, 2001 at about 1:45 am local time, a Bell 47G2 (helicopter), registered N1575, was substantially damaged in an accident near Ardmore, Oklahoma. It was an instructional flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
the loss of tail rotor control during maneuvering resultant from the failure of the tail rotor drive shaft coupling due to a stripped thread which allowed the grease lubricating the shaft to leak out. A factor was the lack of suitable terrain for the forced landing (autorotation).
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- March 22, 2001 · about 1:45 am local time
- Place
- Ardmore, Oklahoma · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell 47G2 · all 47G2s on the register
- Registration
- N1575 · no longer on the register · serial 57
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
During a night flight, the helicopter was in level flight, about 1,400 feet MSL over a lake as the student pilot commenced a turn to the left with a forward airspeed of about 45 to 50 knots. The CFI then "came onto the controls" to assist with the coordinated turn, and noticed that the cockpit turn indicator showed that the helicopter was "slipping." Subsequently, the CFI applied left pedal to correct, and as soon as the left pedal was applied, the airframe shuddered and started to yaw to the right. The airspeed started to decrease and the helicopter began to "spin to the right rapidly." The CFI then applied full left pedal and the helicopter continued to spin to the right. After lowering the collective and reducing the throttle, the helicopter stopped spinning. The CFI then lowered the nose and maneuvered the helicopter toward shallow water near the heavily vegetated shoreline, flaring and pulling up on the collective to cushion the landing. The helicopter came to rest on its left side in the shallow water. Examination of the helicopter revealed that the splined coupling at the aft end of the forward tail rotor drive shaft segment was damaged. Removal of the dust cover for the coupling revealed that the screw and washer, part numbers AN501A10-4 and AN960-10, were loose with several of the threads stripped, thus allowing grease to weep during operation. The forward tail rotor drive shaft assembly, part number 47-644-18-9, was replaced on January 29, 2001. The helicopter had accumulated 70 hours of flight time since the last 100- hour inspection and 23 hours since the last 50- hour lubrication.
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: flight instructor, commercial pilot
- Ratings: instructor: helicopter; instrument: helicopter; rotorcraft: helicopter
- Flight time: 333 hours in all; 30 in this make and model; 150 in the last 90 days; 67 in the last 30 days; 304 as pilot in command; 85 on instruments
- Last flight review: October 3, 2000
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: rgt
- Injury: no injuries
Dual student
- Certificate: private, student
- Ratings: single-engine land; instrument: airplane
- Flight time: 231 hours in all; 16 in this make and model
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 11,736 hours
- Last inspection: 100-hour inspection, February 22, 2001; 70 hours since
- Maximum gross weight: 2,450 lb
- Seats: 3
- Landing gear: fixed
- Engine: Lycoming VO-435-AID (piston); 0 hours total
- Operator: Versatile Helicopters Inc.
The flight
- Departed from: 1F0 Ardmore OK at 1:35 am
- Destination: 1F0
- Flight plan: none
Weather at the time
- Light: night, dark
- Wind: from 160° at 5 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 61°F (16°C), dew point 45°F (7°C)
- Altimeter: 30.00 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 2 |
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 N1575 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.