# Accident 20190923013579A: Piper PA-18-150, Boulder, CO, September 23, 2019

- Type: FAA accident report (Accident/Incident Data System), as reported
- Date: September 23, 2019, 14:20 local time
- Place: Boulder, CO
- Airport: Boulder Municipal
- Damage: Substantial damage
- Phase of flight: Landing: Rollout
- Operating rules: General operating rules (Part 91)
- Location: 40.0394° N, 105.2261° W: From the FAA
- Nearby events: https://openairdocs.org/map.md?lat=40.0394&lon=-105.2261&mi=10
- Aircraft: N4785F, registered now (https://openairdocs.org/aircraft/N4785F) (OpenAirDocs)
- Registry model: Piper PA-18-150 (registry code 7101828, https://openairdocs.org/model/piper-pa-18-150) (OpenAirDocs)
- Registry engine: Lycoming O&VO-360 series (registry code 41514, https://openairdocs.org/engine/lycoming-o-vo-360-series) (OpenAirDocs)
- Reported make and model: PIPER PA-18-150
- Reported engine: LYCOMING O&VO-360 SER
- People aboard: 2
- Fatal injuries: 0
- Other injuries: 0
- Pilot certificates: Airline transport, flight instructor
- Pilot flight hours: 20,382 total, 24 in this make and model, 58 in the last 90 days
- NTSB investigation: [NTSB GAA19CA572](https://openairdocs.org/ntsb/GAA19CA572) (OpenAirDocs)
- FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/)
- Page: https://openairdocs.org/incident/20190923013579A

## Narrative

As the FAA filed it, in capitals; the FAA replaces private details with ^PRIVACY DATA OMITTED^.

THE PIC STATED THAT ON SEPTEMBER 23, 2019 AT APPROXIMATELY 1400 LOCAL, HE HAD A STABILIZED APPROACH TO RUNWAY 08 AT KBDU IN BOULDER, CO. THE PILOT STATED AND IT WAS CONFIRMED THAT WINDS WERE CALM AT THE TIME OF THE ACCIDENT. THE PILOT STATED THAT THE LANDING WAS NORMAL AND THEN FOR AN UNKNOWN REASON HE LOST DIRECTIONAL CONTROL OF THE AIRCRAFT RESULTING IN A GROUND LOOP. VISUAL OBSERVATIONS OF THE AIRCRAFT SHOW EXPECTED GROUND LOOP DAMAGE.

SLIGHT SCUFF MARKS ON THE LEFT HAND MAIN TIRE OUTBOARD SIDEWALL AND MINOR DAMAGE TO THE OUTBOARD WHEEL HALF RIM.

DAMAGE AT THE LEFT HAND WING TIP WITH THE TRAILING EDGE OF THE WING TIP BEND UPWARD WITH PROBABLE DAMAGE TO THE AFT SPAR.

TORN FABRIC ON THE LOWER SURFACE OF THE TRAILING EDGE OF THE WING TIPS EXPOSING THE INTERNAL STRUCTURE OF THE WING.

VISIBLE WRINKLING IN THE UPPER LEFT WING FABRIC, TRAILING EDGE OF THE WING INBOARD OF THE UPPER AILERON CABLE FEED THROUGH.

DAMAGE TO THE LEFT HAND AILERON, VISIBLE CREASE AT THE AILERON UPPER CABLE ATTACH POINT WITH THE OUTBOARD OF THE ATTACH POINT DEFLECTING UPWARD.

MINOR SCRAP DAMAGE TO THE LOWER OUTBOARD TRAILING EDGE OF THE LEFT HAND ELEVATOR, AND

DAMAGE TO THE RUDDER WITH THE LOWER 1/3 OF THE RUDDER DEFLECTING TO THE RIGHT.

NO OTHER NOTABLE OBSERVATIONS AFTER LOOKING AT THE TAILWHEEL, BRAKES, RUDDER PEDALS, HEEL BRAKES AND MASTER CYLINDERS.

## The NTSB's investigation of this event (1)

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB GAA19CA572](https://openairdocs.org/ntsb/GAA19CA572), Sep 23, 2019: Piper PA18 (N4785F), Boulder, CO, substantial damage. Probable cause: The pilot's failure to maintain directional control during the landing roll, which resulted in a ground loop.

## Other reports on N4785F (3)

Matched to the same aircraft by N-number and date.

- [Accident 20150316003149A](https://openairdocs.org/incident/20150316003149A), Mar 16, 2015: Piper PA-18-150 (N4785F), Boulder, CO, Substantial damage. On 03/16/2015 at 0815 hrs MDT,N4785F a Piper PA-18-150 was damaged when the aircraft left the runway an impacted a berm. Single pilot was uninjured. Weather at…
- [Accident 20000708010469A](https://openairdocs.org/incident/20000708010469A), Jul 8, 2000: Piper PA18150 (N4785F), Erie, CO, No damage. (-23) Pilot terry was checking pilot mainero out in the glider club's tow plane and during landing mainero lost control of the aircraft. Pilot terry took…
- [Accident 19990701007999A](https://openairdocs.org/incident/19990701007999A), Jul 1, 1999: Piper PA18150 (N4785F), Boulder, CO, Substantial damage. Acft flipped over on landing, other circumstances are unknown. (-23)no narrative

From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. For accidents, the NTSB's own investigation is the fuller record.

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