Cessna 140 accident near Helena, Montana, December 15, 1999
On December 15, 1999 at about 10:30 pm local time, a Cessna 140, registered N2739N, was substantially damaged in an accident near Helena, Montana (Silver City 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
Separation of the left main landing gear. Factors include inadequate preflight inspection by the pilot, and inadequate inspection at the time of annual inspection by maintenance personnel.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- December 15, 1999 · about 10:30 pm local time
- Place
- Helena, Montana · Silver City · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 140 · all 140s on the register
- Registration
- N2739N · no longer on the register · serial 12997
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot stated that on his second touch-and-go landing at the airstrip, about half way down the runway, the left wheel separated and the airplane nosed over. FAA inspectors observed that the left wheel and gear extension had separated from the left main landing gear leg and were found off the runway on the left side. Surface tracks indicated that the airplane had been tracking along the centerline of the runway, and that the airplane had continued to track down the centerline for an additional 30 yards before it nosed over. The four left main landing gear extension attachment bolts were inspected by the NTSB's material laboratory. Examination revealed that all four bolts were bent through the shank portion; however, none of the bolts were separated. Additionally, the threads in each bolt were scraped on the convex side of the bend, as if from sliding out of the bolt hole. Three of the four bolts exhibited what appeared to be stripped threads of their corresponding nuts in their thread grooves. No evidence was found of the presence of a nut on the fourth bolt. Records revealed that the airplane had received an annual inspection on November 11, 1999, and it had accumulated seven hours of operation since that 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: 216 hours in all; 8 in this make and model; 10 in the last 90 days; 8 in the last 30 days; 169 as pilot in command
- Medical certificate: Class 3 (expired)
- Seat: left
The aircraft
- Airframe total time: 2,341 hours
- Last inspection: annual inspection, November 11, 1999; 7 hours since
- Maximum gross weight: 1,450 lb
- Seats: 2
- Landing gear: fixed
- Engine: Continental C-85-12 (piston); 0 hours total
The flight
- Departed from: HLN Helena MT at 9:00 pm
- Flight plan: none
- Runway 8, 4,000 ft by 85 ft
Weather at the time
- Light: daylight
- Visibility: 20 statute miles
- Sky: clear
- Temperature: 30°F (-1°C), dew point 0°F (-18°C)
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.