# NTSB FTW84LA373: Cessna 172M, N9646H, Bethany, OK, August 30, 1984

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: August 30, 1984, 14:25 local (19:25 UTC)
- Place: Bethany, OK
- Coordinates: 35.50069, -97.639106 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=35.5007&lon=-97.6391&mi=10
- Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 4 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 21448
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW84LA373
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/21448/pdf
- Page: https://openairdocs.org/ntsb/FTW84LA373

## Sequence of events

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

- On ground/water collision with object, taxi - to takeoff
  - object - aircraft moving on ground (contributing factor)
  - visual lookout - inadequate, pilot of other aircraft (cause)
- On ground/water collision with object, taxi - to takeoff
  - object - aircraft moving on ground (contributing factor)
  - visual lookout - inadequate, pilot in command (cause)

## Analysis (aircraft 2)

ACCORDING TO THE PLT OF N9646H, WHILE HE WAS TAXIING UNDER THE DIRECTION OF GROUND CONTROL THE ACFT WAS STRUCK FROM BEHIND BY N1PN. THE PLT OF N1PN STATED THAT HE WAS CLEARED TO TAXI AND DID NOT SEE ANY OTHER ACFT AS HE ENTERED THE TAXIWAY. SEATED IN THE REAR SEAT OF THE TANDEM SEAT ACFT THE PLT OF N1PN WAS PERFORMING 'S' TURNS IN AN EFFORT TO MAINTAIN VISUAL CLEARANCE WHEN THE WING OF N9646H WAS SEEN ALMOST SIMULTANEOUS WITH THE COLLISION. INITIAL CONTACT OCCURRED BETWEEN THE PROP OF THE OVERTAKING ACFT AND THE EMPENNAGE OF THE LEADING ACFT.

## Aircraft 1

- Registration: [N9646H](https://openairdocs.org/deregistered/N9646H-1991-04-10), registration cancelled 1991-04-10, S/N 17266293 (OpenAirDocs)
- Reported make and model: CESSNA 172M
- Registry model: [Cessna 172M](https://openairdocs.org/model/cessna-172m) (registry code 2072418) (OpenAirDocs)
- Category: Airplane
- Serial number: 17266293
- Airframe hours: 3121
- Engines: LYCOMING O-320-E2D 150 horsepower reciprocating
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Operator: Ollis B Harrison
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, August 23, 1984
- Airport: Wiley Post Airport

## Aircraft 2

- Registration: N1PN (not matched to a registry record)
- Reported make and model: de Havilland DHC-1B-2-S5 (DHC-1B-2-S)
- Category: Airplane
- Serial number: 231
- Airframe hours: 3290
- Engines: LYCOMING O-540 235 horsepower reciprocating
- Damage: Minor damage
- Flight: Personal, Part 91
- Operator: Thunderbird Park Inc
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Annual, June 8, 1984, 0 hours before
- Airport: Wiley Post Airport

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot, aircraft N9646H; age 37; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 4,034 total, 482 in this make and model, 3,793 as pilot in command, 56 in the last 90 days, 1 in the last 24 hours
- Pilot, aircraft N1PN; age 58; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, valid medical--w/ waivers/lim; seat: rear; flight hours: 1,031 total, 5 in this make and model, 810 as pilot in command, 25 in the last 90 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 230° at 5 knots
- Visibility: 25 statute miles
- Lowest ceiling: none
- Temperature: -0 °F, dew point -0 °F
- Altimeter: 30.00 inHg
- Observed at: PWA

## FAA reports on this event (2)

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

- [Accident 19840830071722A](https://openairdocs.org/incident/19840830071722A), Aug 30, 1984: Cessna 172M, Bethany, OK, Substantial damage. Was overtaken on the taxiway and struck from behind by a chipmunk N1PN. Tower personel failed to warn both pilots.
- [Accident 19840830071721A](https://openairdocs.org/incident/19840830071721A), Aug 30, 1984: Dhav DHC1B2S5, Bethany, OK, Minor damage. Overtook and struck the tail of N9646H on the taxiway. Tower failed to warn pilots. Tail wheel aircraft blind.

## Other investigations on N9646H (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 MKC89FA117](https://openairdocs.org/ntsb/MKC89FA117), May 28, 1989: Cessna 172M (N9646H), Oakland, AR, substantial damage. Probable cause: PILOT ELECTING TO BUZZ PERSONS ON THE LAKE AT LOW ALTITUDE AND COLLIDING WITH POWER LINES.

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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