North American AT-6G accident near Longmont, Colorado, July 5, 1998
On July 5, 1998 at about 4:50 pm local time, a North American AT-6G, registered N8399H, was substantially damaged in an accident near Longmont, Colorado (Vance Brand Airport). 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
The partial failure of the tail wheel steering system due to improper maintenance and the subsequent inadvertent ground loop during the landing sequence. Factors were the airport taxiway sign and the subsequent failure of the left main landing gear.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 5, 1998 · about 4:50 pm local time
- Place
- Longmont, Colorado · Vance Brand Airport
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- North American AT-6G · all AT-6Gs on the register
- Registration
- N8399H · no longer on the register · serial 49-3190
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot was given airport advisories on unicom. He was told that the active runway was 29 and that the wind was 'light and variable.' He said that the 'windsock's movement was hardly perceptible and the velocity of the indicator indicated less than 5 knots.' The pilot reported that after touchdown, 'the aircraft's rollout path took multiple, short, quick inputs from the rudder to keep properly aligned with the runway centerline as the aircraft proceeded down the runway.' He further reported the rudder inputs became ineffective after approximately 400 to 500 feet of landing roll and the aircraft exited the right side of the runway. The aircraft subsequently impacted an airport taxiway sign, damaging the left main landing gear and the left wing. The aircraft came to rest with its nose down. The pilot said that the tail wheel steering cables had recently been replaced. Postaccident evaluation of the tail wheel steering cables by maintenance personnel found a tension of 5 pounds on these cables; 20 pounds is considered normal.
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, commercial pilot, flight engineer
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane
- Flight time: 11,600 hours in all; 60 in this make and model; 250 in the last 90 days; 80 in the last 30 days; 3,200 as pilot in command; 210 on instruments
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: frt
The aircraft
- Airframe total time: 4,950 hours
- Last inspection: annual inspection, June 19, 1998; 7 hours since
- Maximum gross weight: 5,300 lb
- Seats: 2
- Landing gear: retractable
- Engine: P&W R1340-AN1 (piston); 0 hours total
The flight
- Departed from: APA Denver CO at 4:00 pm
- Destination: 2V2
- Flight plan: none
- Runway 29, 4,800 ft by 75 ft
Weather at the time
- Light: daylight
- Wind: from 350° at 7 knots
- Visibility: 80 statute miles
- Sky: scat at 9,000 ft
- Temperature: 84°F (29°C), dew point 50°F (10°C)
- Altimeter: 30.00 inHg
- Observation at 4:46 pm from BJC, 20 miles away
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.