Amateur-built RANS S-6S accident near Roberts, Idaho, September 18, 2010
On September 18, 2010 at about 3:10 pm local time, a amateur-built RANS S-6S, registered N4427M, was substantially damaged in an accident during takeoff near Roberts, Idaho (Tanner Airstrip airport). It was a personal flight under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A loss of engine power due to the detachment of the left carburetor from the engine inlet manifold. Contributing to the accident was the pilot's failure to address a known engine vibration.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 18, 2010 · about 3:10 pm local time
- Place
- Roberts, Idaho · Tanner Airstrip · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built RANS S-6S
- Registration
- N4427M · registry record · serial 08031518-S
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot, who was also the airplane's owner, reported that the engine of the experimental amateur-built airplane experienced a partial loss of power while turning onto the crosswind leg of the traffic pattern after the initial takeoff climb. The pilot initiated a return to the runway, during which time the engine lost all power. The pilot unsuccessfully attempted to restart the engine and subsequently performed an off-airport landing. The airplane's right main landing gear collapsed during the landing roll, resulting in substantial damage to the airframe. Examination of the engine revealed that the left carburetor was detached from the engine inlet manifold. The impact trajectory, coupled with a lack of witness marks indicating the carburetor had struck any part of the airplane, make it most likely that the carburetor detached in flight. The owner/pilot reported that he had experienced excessive engine vibration and "kickback" during prior startups. He had considered a number of remedial measures to rectify the problem, but had not performed any of these measures prior to the accident flight. He additionally reported that he could have reduced the likelihood of the carburetor separating by more thoroughly examining the tension of its mounting hardware.
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
- Aircraft inspection event during prior to flight
- Loss of engine power (partial) during takeoff defining event
- Loss of engine power (total) during takeoff
- Collision with terrain or object (not controlled flight into terrain) during landing (flare/touchdown)
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine fuel and control › Fuel control/carburetor › Inadequate inspection
- cause Aircraft › Aircraft power plant › Engine fuel and control › Fuel control/carburetor › Damaged/degraded
- factor Personnel issues › Task performance › Inspection › Scheduled/routine inspection › Pilot
- factor Personnel issues › Task performance › Maintenance › Modification/alteration › Pilot
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 2,473 hours in all; 445 in this make and model; 2,473 as pilot in command
- Last flight review: July 16, 2009
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 429 hours
- Last inspection: condition inspection, July 19, 2010; 16 hours since
- Seats: 2
- Landing gear: fixed
- Engine: Rotax 912ULS (piston); 0 hours total
The flight
- Departed from: PVT Roberts ID at 3:10 pm
- Destination: U56 Rigby ID
- Flight plan: none
- Runway 20, 1,500 ft by 100 ft
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 54°F (12°C), dew point 43°F (6°C)
- Altimeter: 30.02 inHg
- Observation at 2:53 pm from IDE, 18 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.
Other NTSB records under N4427M 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.