# NTSB DEN92LA009: Cessna 172N, N80893, Boulder, CO, November 20, 1991

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: November 20, 1991, 10:10 local (17:10 UTC)
- Place: Boulder, CO
- Coordinates: 40.019565, -105.250221 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=40.0196&lon=-105.2502&mi=10
- Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report July 13, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 18180
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN92LA009
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/18180/pdf
- Page: https://openairdocs.org/ntsb/DEN92LA009

## Probable cause

FAILURE OF THE PILOT TO MAINTAIN CLEARANCE FROM THE SIGN.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- On ground/water collision with object, taxi - from landing
  - object - sign
  - clearance - not maintained, pilot in command (cause)

## Analysis

WITH THE EXCEPTION OF THE FIRST RUNWAY TURNOFF, ALL RUNWAY TURNOFFS WERE SUPPOSED TO BE BARRICADED CLOSED FOR TAXIWAY MAINTENANCE.  THE PILOT LANDED BUT WAS UNABLE TO EXIT AT THE FIRST TURNOFF.  THE SECOND TURNOFF WAS BARRICADED CLOSED. THE PILOT TAXIED TO THE END OF THE RUNWAY AND FOUND THIS TURNOFF WAS NOT BARRICADED.  IT SHOULD HAVE BEEN.  THE PILOT TAXIED BACK TOWARDS BACK OF THE AREA OF THE FIRST TURNOFF, HE FOUND THE TAXIWAY WAS BARRICADED.  HE SAW A SMALL DIRT ROAD EXITING THE TAXIWAY AND THOUGHT IT WAS A TEMPORARY TAXIWAY ERECTED BY THE MAINTENANCE CREW.  WHILE TAXIING TOWARDS THE RAMP ON THIS ROAD, THE AIRPLANE'S RIGHT WING STRUCK A SIGN.  THE AIRPLANE SPUN AROUND AND THE TAIL STRUCK A BARBED WIRE FENCE.

## Aircraft

- Registration: [N80893](https://openairdocs.org/deregistered/N80893-2012-01-05), registration cancelled 2012-01-05, S/N 17266791, built 1976 (OpenAirDocs)
- Reported make and model: CESSNA 172N
- Registry model: [Cessna 172M](https://openairdocs.org/model/cessna-172m) (registry code 2072418) (OpenAirDocs)
- Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 17266791
- Engines: LYCOMING O-320-H2AD 160 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Dakota Ridge Aviation
- Airport: IV5, Boulder Municipal

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 25; private; airplane ratings: single-engine land; medical: class 3, valid medical--no waivers/lim.; flight hours: 66 total, 66 in this make and model, 43 as pilot in command, 5 in the last 90 days, 2 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 50 statute miles
- Lowest ceiling: none
- Temperature: -0 °F, dew point -0 °F

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19911120056759A](https://openairdocs.org/incident/19911120056759A), Nov 20, 1991: Cessna 172N, Boulder, CO, Substantial damage. Wing struck a sign while taxiing to ramp. Had tried to circumnavigate a closed taxiway. NOTAMS on closed taxiways.

## Other investigations on N80893 (2)

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 FTW95LA110](https://openairdocs.org/ntsb/FTW95LA110), Feb 6, 1995: Cessna 172M (N80893), Boulder, CO, substantial damage. Probable cause: THE PILOT'S PREMATURE ROTATION.
- [NTSB DEN89LA143](https://openairdocs.org/ntsb/DEN89LA143), Jun 20, 1989: Cessna 172M (N80893), Boulder, CO, substantial damage. Probable cause: INADEQUATE COMPENSATION FOR WIND CONDITIONS BY THE (PRIVATE RATED) DUAL STUDENT AND HIS FAILURE TO MAINTAIN DIRECTIONAL CONTROL, WHICH RESULTED IN AN INADVERTENT GROUND SWERVE, AND INADEQUATE…

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.

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