Piper PA-31 accident near Boise, Idaho, August 6, 1995
On August 6, 1995 at about 5:50 pm local time, a Piper PA-31, registered N9111Y, was substantially damaged in an accident near Boise, Idaho. 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
improper adjustment of the engine fuel control units by company maintenance personnel which led to excessive fuel flow and subsequent partial loss of engine power. Factors contributing to the accident were the rough terrain and high density altitude.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 6, 1995 · about 5:50 pm local time
- Place
- Boise, Idaho · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Piper PA-31 · all PA-31s on the register
- Registration
- N9111Y · no longer on the register · serial 31-148
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
After flying the airplane earlier in the day, the pilot-in-command (Chief Pilot} requested that the engines receive an adjustment for improved performance. The Director of Maintenance performed the adjustments by adjusting the fuel mixture control units on both engines. After the adjustment, the PIC and dual student departed for a Part 135 training flight. No problems were noted during the preflight inspection, engine start-up, taxi, engine run-up, and initial takeoff roll. During climbout, the airplane was unable to climb. The PIC stated that the right engine had a power problem due to the low manifold pressure and he feathered the right propeller to arrest the airplane's descent rate. The airplane continued to descend, and the dual student made the forced landing on rough terrain. Examination of the spark plugs revealed that the engines were operating with an excessively rich mixture. The density altitude was 5,560 feet. This was the dual student's first flight in a Piper PA-31.
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: airline transport pilot, flight instructor
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane
- Flight time: 3,925 hours in all; 227 in this make and model; 205 in the last 90 days; 73 in the last 30 days; 3,815 as pilot in command; 2,550 on instruments
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 8,460 hours
- Last inspection: 100-hour inspection, July 1, 1995; 8 hours since
- Maximum gross weight: 6,500 lb
- Seats: 2
- Landing gear: retractable
- Engine: Lycoming TIO-540-A2C (piston); 0 hours total
- Operator: H & H Aviation, INC.
The flight
- Departed from: BOI ID at 5:45 pm
- Flight plan: none
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 340° at 9 knots
- Visibility: 45 statute miles
- Sky: clear
- Temperature: 88°F (31°C), dew point 41°F (5°C)
- Altimeter: 29.00 inHg
- Observation at 5:55 pm from BOI, 2 miles away
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.
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.