# NTSB DEN84LA165: Cessna 172M, N73561, Cheyenne, WY, May 31, 1984

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: May 30, 1984, 20:00 local (May 31, 1984, 02:00 UTC)
- Place: Cheyenne, WY
- Coordinates: 41.140094, -104.790061 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=41.1401&lon=-104.7901&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor, 3 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 16388
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN84LA165
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/16388/pdf
- Page: https://openairdocs.org/ntsb/DEN84LA165

## Sequence of events

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

- In flight encounter with weather, takeoff - initial climb
  - weather evaluation - improper, pilot in command (cause)
  - flight into known adverse weather - initiated
  - weather condition - high density altitude (contributing factor)
  - weather condition - thunderstorm (contributing factor)
  - weather condition - downdraft (contributing factor)
  - weather condition - turbulence(thunderstorms) (contributing factor)
- Loss of control - in flight, takeoff
  - climb - not possible
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

BEFORE THE FLIGHT THE PILOT OBTAINED A WEATHER BRIEFING AND WAS INFORMED OF AN APPROACHING THUNDERSTORM WHICH WAS 10 MILES NORTHWEST OF THE AIRPORT. THE PILOT STATED THAT AFTER A NORMAL TAKEOFF HE CLIMED TO A ALTITUDE OF ABOUT 250 FT AGL, AT 70 KIAS, WHEN HE EXPERIENCED MODERATE TURBULENCE AND THE CLIMB LEVELED OFF. THE PLT THEN CHECKED THE ALTIMETER AND VERTICAL SPEED INDICATOR WHICH HE SAID INDICATED A DESCENT EVEN THOUGH HIS AIRSPEED AND ATTITUDE INDICATED THE ACFT SHOULD BE CLIMBING. UNABLE TO ARREST THE DESCENT, THE ACFT SETTLED INTO AN OPEN FIELD. THE REPORTED CHEYENNE WINDS AT 1959 MDT WERE FROM 340 DEGREES AT 25 KTS GUSTING TO 38 KTS. AT 2052 MDT THE WINDS WERE REPORTED TO BE FROM 020 DEGREES AT 8 KTS. THE THUNDERSTORM WHICH PASSED OVER CHEYENNE AT 1907 MDT WAS REPORTED TO BE A STORM OF LEVEL 1 INTENSITY. THE ELEVATION OFTHE ARPT WAS 6156 FT.

## Aircraft

- Registration: N73561 (not matched to a registry record)
- Reported make and model: CESSNA 172M
- Category: Airplane
- Serial number: 17267540
- Airframe hours: 765
- Engines: LYCOMING O-320-E2D 150 horsepower reciprocating
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Operator: Chemaire Corp
- Registered owner: Diversity Investments
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, April 21, 1984, 507 hours before
- Destination: 7V5, BRUSH, CO
- Airport: CYS, Cheyenne, runway 30, 6,691 × 150 ft, grass/turf

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 26; flight instructor, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: right; flight hours: 575 total, 328 in this make and model, 333 as pilot in command, 82 in the last 90 days, 5 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 340° at 25 knots, gusting 38
- Visibility: 60 statute miles
- Lowest ceiling: 8,000 ft broken
- Temperature: 73 °F
- Altimeter: 30.00 inHg
- Observed at: CYS, 1 nm away

## 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 19840530020209A](https://openairdocs.org/incident/19840530020209A), May 30, 1984: Cessna 172M, Cheyenne, WY, Substantial damage. Encountered a windshear on initial climb. Settled to ground off end of the runway. A thunderstorm was nearby.

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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