Arctic Aircraft Company S-1B2 accident near Anchorage, Alaska, March 19, 2005
On March 19, 2005 at about 8:15 pm local time, a Arctic Aircraft Company S-1B2, registered N67AT, was substantially damaged in an accident near Anchorage, Alaska. It was a personal 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
A main landing gear collapse during the landing touch down due to a non-secured clevis bolt at the common attach point on the landing gear oleo shock.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- March 19, 2005 · about 8:15 pm local time
- Place
- Anchorage, Alaska · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Arctic Aircraft Company S-1B2
- Registration
- N67AT · registry record · serial 1018
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The private certificated pilot was conducting short-field landings with the wheels extended on a frozen lake in a wheel/ski-equipped airplane. On the ninth landing, the main landing gear collapsed, and the airplane settled onto its belly. The pilot said both landing gear A-frame type gear assemblies rotated outward and upward, as the airplane settled onto the ice. He said that the touchdown was not hard, and the common point of failure was at the center, fuselage-mounted spring shock assembly. Each landing gear assembly has an extended arm that attaches in the center of the fuselage to the bottom end of a vertically mounted oleo shock. The left gear arm attaches to the oleo lug by a clevis bolt that is installed front-to-back. The bolt also retains the top end of two oval-shaped metal link plates that are positioned vertically at the front and aft side of the oleo attach lug. A clevis bolt, through the bottom hole of each link, retains a spacer and the right landing gear extended attaching arm. Each clevis bolt uses a tension castle nut, with a cotter pin for security. The aft link plate had extensive elongation of the upper bolt hole radius. The forward link plate upper bolt hole was fractured, and had opening and elongation of a segment of the bolt hole radius. The upper clevis bolt was found at the scene, but its castle nut and cotter pin were not located. The clevis bolt was bent along its span. The threaded portion of the bolt had flattening of the threads about 1/3 of its circumference, and partial threads on the remaining 2/3 of its circumference, with slight necking of the bolt end. An FAA aerospace engineer examined the recovered parts and reported, in part, that: "...the cotter pin failed in service, or was never installed, and the shear nut loosened and fell off the aft end of the upper bolt, or was never installed." The airplane had accrued 11 hours since the most recent annual inspection.
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: private
- Ratings: single-engine land
- Flight time: 383 hours in all; 212 in this make and model; 12 in the last 90 days; 3 in the last 30 days; 261 as pilot in command
- Last flight review: January 1, 2005
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: frt
- Injury: no injuries
The aircraft
- Airframe total time: 1,131 hours
- Last inspection: annual inspection, August 1, 2004; 11 hours since
- Maximum gross weight: 1,650 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming O-320-B2B (piston); 0 hours total
The flight
- Departed from: PAMR Anchorage AK at 7:55 pm
- Flight plan: none
Weather at the time
- Light: daylight
- Visibility: 20 statute miles
- Sky: clear
- Temperature: 37°F (3°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 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.