Piper PA18 accident near Boulder, Colorado, September 23, 2019
On September 23, 2019 at about 8:20 pm local time, a 1962 Piper PA18, registered N4785F, was substantially damaged in an accident during landing near Boulder, Colorado (Boulder Muni 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 pilot's failure to maintain directional control during the landing roll, which resulted in a ground loop.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 23, 2019 · about 8:20 pm local time
- Place
- Boulder, Colorado · Boulder Muni · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Piper PA18 150, built 1962 · all PA18s on the register
- Registration
- N4785F · registry record · serial 18-7906
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported that he conducted a normal three-point landing. During the landing roll, the airplane ground looped to the left, and the left wing struck the ground. The airplane sustained substantial damage to the left wing spar and the rudder. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.
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
- Loss of control on ground during landing defining event
The NTSB's findings
- cause Personnel issues › Task performance › Use of equip/info › Aircraft control › Pilot
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Directional control › Not attained/maintained
Pilot
- Certificate: airline transport pilot, flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane; rotorcraft: glider
- Flight time: 20,403 hours in all; 24 in this make and model; 58 in the last 90 days; 5 in the last 30 days; 6,169 as pilot in command; 3,824 on instruments
- Last flight review: August 16, 2019
- Medical certificate: Class 1 (with waivers/limitations)
- Seat: frt
- Injury: no injuries
The aircraft
- Airframe total time: 15,624.7 hours
- Last inspection: annual inspection, June 7, 2019
- Maximum gross weight: 1,750 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming O-360-A3A (piston); 2,567 hours total
- Operator: Soaring Society Of Boulder Inc
The flight
- Departed from: BDU Boulder CO at 7:38 pm
- Destination: BDU Boulder CO
- Flight plan: none
- Runway 08, 4,100 ft by 75 ft
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 77°F (25°C), dew point 28°F (-2°C)
- Altimeter: 30.07 inHg
- Observation at 8:12 pm from KBDU, 1 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
2 documents, released by the NTSB on January 3, 2020. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 9 pages | View Download |
| 2 | Photo | PDF, 1 page | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Other NTSB records under N4785F 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.