Bell UH-1L accident near Grace, Idaho, September 18, 1995
On September 18, 1995 at about 6:00 pm local time, a Bell UH-1L (helicopter), registered N70410, was destroyed in an accident near Grace, Idaho. It was an other work-use 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 the centrifugal impeller and the lack of suitable terrain for a forced landing. Factors contributing to the accident were: the lack of required compliance with the FAA Airworthiness Directive by the operator, the insufficiently defined FAA procedure within the AD (failure to include the -07 impeller and establish a cycle count program), and inadequate rotor RPM.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 18, 1995 · about 6:00 pm local time
- Place
- Grace, Idaho · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell UH-1L · all UH-1Ls on the register
- Registration
- N70410 · no longer on the register · serial 157855
- Damage
- Destroyed
- Flight
- Other work-use flight · external-load helicopter rules (Part 133)
The NTSB's narrative final · quoted from the NTSB record
During log slinging operations the restricted category UH-1L rotorcraft's T53-L-13B military engine experienced a total loss of power. The pilot dropped the log load and autorotated into a small, upsloping, cleared area within the surrounding wooded terrain landing hard. Postcrash examination of the engine revealed that the centrifugal impeller had separated due to fatigue cracking in one of the drain holes. An Airworthiness Directive (AD) had been issued relative to the -08 impeller but did not include the -07 impeller (installed in the accident engine). The -07 and -08 impellers are essentially identical with the exception that the -07 impeller is found on military variants of the engine whereas the -08 is found only on civilian variants. As the -07 impeller was not included in the AD, the operator was not required to conduct the appropriate inspections described in the mandated service bulletin. Additionally, the AD did not require a cycle count for the impeller as addressed in the service bulletin, thus rendering the service bulletin unusable even if it had been mandated for the -07 impeller.
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: multi-engine land; single-engine land; instrument: airplane; rotorcraft: helicopter
- Flight time: 16,500 hours in all; 2,500 in this make and model; 16,500 as pilot in command
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 9,475 hours
- Last inspection: continuous airworthiness programme, September 9, 1995; 64 hours since
- Maximum gross weight: 9,500 lb
- Seats: 6
- Landing gear: fixed
- Engine: Lycoming T53-L-13B (turboshaft); 0 hours total
- Fire on the ground
The flight
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 280° at 9 knots
- Visibility: 30 statute miles
- Sky: clear
- Temperature: 72°F (22°C), dew point 48°F (9°C)
- Altimeter: 30.00 inHg
- Observation at 5:56 pm from PIH, 47 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| 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.