# NTSB WPR09CA348: Cessna 172M, N5461Q, Thermopolis, WY, July 16, 2009

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Data collection · Final report
- Date: July 15, 2009, 23:35 local (Jul 16, 2009, 05:35 UTC)
- Place: Thermopolis, WY
- Coordinates: 43.508609, -108.078056
- Nearby events: https://openairdocs.org/map.md?lat=43.5086&lon=-108.0781&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Defining event: [Enroute-descent: Controlled flight into terr/obj (CFIT)](https://openairdocs.org/ntsb-events/120)
- Highest injury: Serious injuries
- Injuries: 1 serious, 1 minor
- Status: Completed, report September 30, 2009
- Report: Approved by Office Director
- NTSB office: Western Pacific Region
- Parties: Casper FSFO
- NTSB case key (mKey): 74303
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR09CA348
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/74303/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=74303
- Page: https://openairdocs.org/ntsb/WPR09CA348

## Probable cause

The instructor pilot's failure to ensure that his dual student maintained clearance from the terrain during a dark night visual flight rules descent.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Performance/control parameters: descent/approach/glide path](https://openairdocs.org/ntsb-findings/01062040): Aircraft › Aircraft oper/perf/capability · Incorrect use/operation (probable cause); cases with it: [Cessna 172M, 15 cases](https://openairdocs.org/ntsb-findings/01062040/cases.md?model=2072418), [All aircraft, 809 cases](https://openairdocs.org/ntsb-findings/01062040/cases.md)
- [Attention/monitoring: monitoring environment](https://openairdocs.org/ntsb-findings/02021545): Personnel issues › Psychological · Student/instructed pilot; cases with it: [Cessna 172M, 15 cases](https://openairdocs.org/ntsb-findings/02021545/cases.md?model=2072418), [All aircraft, 809 cases](https://openairdocs.org/ntsb-findings/02021545/cases.md)
- [Attention/monitoring: monitoring other person](https://openairdocs.org/ntsb-findings/02021535): Personnel issues › Psychological · Instructor/check pilot (probable cause); cases with it: [Cessna 172M, 5 cases](https://openairdocs.org/ntsb-findings/02021535/cases.md?model=2072418), [All aircraft, 200 cases](https://openairdocs.org/ntsb-findings/02021535/cases.md)
- [Light condition: dark](https://openairdocs.org/ntsb-findings/03036020): Environmental issues › Conditions/weather/phenomena · Effect on personnel; cases with it: [Cessna 172M, 8 cases](https://openairdocs.org/ntsb-findings/03036020/cases.md?model=2072418), [All aircraft, 448 cases](https://openairdocs.org/ntsb-findings/03036020/cases.md)
- [Wind: downdraft](https://openairdocs.org/ntsb-findings/03034035): Environmental issues › Conditions/weather/phenomena · Effect on operation; cases with it: [Cessna 172M, 1 case](https://openairdocs.org/ntsb-findings/03034035/cases.md?model=2072418), [All aircraft, 178 cases](https://openairdocs.org/ntsb-findings/03034035/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Enroute-descent: Controlled flight into terr/obj (CFIT)](https://openairdocs.org/ntsb-events/120) (defining event); cases with it: [Cessna 172M, 12 cases](https://openairdocs.org/ntsb-events/120/sequence.md?model=2072418), [All aircraft, 1,074 cases](https://openairdocs.org/ntsb-events/120/sequence.md)

## Analysis

The student pilot and his instructor were returning to their home airport after a visual flight rules (VFR) night cross-country instructional fight. During the last segment of the flight, as the student was descending toward the airport, the airplane's wheels contacted the terrain on a ridge about nine miles from the planned destination, and about 1,650 feet higher than the airport elevation. Although the airplane initially rolled across the terrain at a high rate of speed, it soon encountered the elevated edge of a dirt road. The contact with the road edge resulted in a loss of control of the airplane and further contact with the terrain. The sequence of events resulted in substantial damage to the airplane's fuselage. Although the sky was clear with no restrictions to visibility, it was a dark night with no moonlight, and neither pilot saw the terrain prior to the accident. Although the instructor pilot did not specifically remember an unusual rate of descent or any sense of the airplane sinking, it was his opinion that a "mountain wave downwash" may have contributed to the accident.

## Factual narrative

The student pilot and his instructor were returning to their home airport after a visual flight rules (VFR) night cross-country instructional fight. During the last segment of the flight, as the student was descending toward the airport, the airplane's wheels contacted the terrain on a ridge about nine miles from the planned destination, and about 1,650 feet higher than the airport elevation. Although the airplane initially rolled across the terrain at a high rate of speed, it soon encountered the elevated edge of a dirt road. The contact with the road edge resulted in a loss of control of the airplane and further contact with the terrain. The sequence of events resulted in substantial damage to the airplane's fuselage. Although the sky was clear with no restrictions to visibility, it was a dark night with no moonlight, and neither pilot saw the terrain prior to the accident. Although the instructor pilot did not specifically remember an unusual rate of descent or any sense of the airplane sinking, it was his opinion that a "mountain wave downwash" may have contributed to the accident.

## Aircraft

- Registration: [N5461Q](https://openairdocs.org/deregistered/N5461Q-2013-04-18), registration cancelled 2013-04-18, S/N 17261791, built 1973 (OpenAirDocs)
- Reported make and model: CESSNA 172M
- 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: 17261791
- Engines: LYCOMING O-320 SERIES 180 horsepower reciprocating
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Operator: Round Top Flyers LLC
- Registered owner: Round Top Flyers LLC
- Airworthiness certificate: Standard, Normal
- Departed: KLND, Lander, WY
- Destination: KTHP, Thermopolis, WY
- Flight plan: Unknown

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Flight instructor; age 68; injuries: minor; commercial, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 3; seat: right; flight hours: 3,784 total, 1,800 in this make and model
- Student pilot; age 47; injuries: serious; student; medical: class 3; seat: left; flight hours: 27 total, 27 in this make and model

## Weather

- Conditions: Visual (VMC), Night/dark
- Wind: 330° at 15 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 50 °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 20090715011619A](https://openairdocs.org/incident/20090715011619A), Jul 15, 2009: Cessna 172M, Thermopolis, WY, Substantial damage. (-23) Student pilot decended into hight terrain during night approach to airport. Altimeter was set to 3020 and riverton AWOS reporting called out 3026.

## Other investigations on N5461Q (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 MKC77DCQ22](https://openairdocs.org/ntsb/MKC77DCQ22), Mar 10, 1977: Cessna 172 (N5461Q), Coats, KS, substantial damage

## Docket (1 files)

The files NTSB released with the investigation on July 28, 2009, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=74303. 1.9 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40316497&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF

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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