# NTSB SEA93GA041: Cessna 550, N6887Y, Billings, MT, December 18, 1992

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Final report
- Date: December 18, 1992, 16:45 local (23:45 UTC)
- Place: Billings, MT
- Coordinates: 45.649234, -108.379302 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=45.6492&lon=-108.3793&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 8 fatal
- Status: Completed, report December 9, 1993
- Report: Approved by Office Director
- Safety recommendations: Yes
- NTSB case key (mKey): 42941
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA93GA041
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/42941/pdf
- Page: https://openairdocs.org/ntsb/SEA93GA041

## Probable cause

THE PILOT-IN-COMMAND'S FAILURE TO FOLLOW ESTABLISHED VORTEX AVOIDANCE PROCEDURES, AS PUBLISHED IN THE AIRMAN'S INFORMATION MANUAL, TO PROVIDE HIS OWN WAKE TURBULENCE SEPARATION.

## Sequence of events

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

- Vortex turbulence encountered, approach
  - procedures/directives - not followed, pilot in command (cause)
  - wake turbulence - encountered (cause)
- Loss of control - in flight, approach
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

DURING DESCENT INTO BILLINGS, THE CITATION WAS SEQUENCED BEHIND A BOEING 757, AND BOTH AIRPLANES WERE EVENTUALLY CLEARED FOR VISUAL APPROACHES. ABOUT 1-1/2 MI FROM THE RUNWAY THE CITATION WAS OBSERVED TO ROLL RAPIDLY TO THE INVERTED POSITION & DESCEND ALMOST VERTICALLY INTO THE GROUND. ACCORDING TO ATC TRANSCRIPTS AND THE AIRPLANES'S COCKPIT VOICE RECORDER, THE CREW OF THE CITATION HAD MAINTAINED VISUAL AWARENESS OF THE POSITION OF THE B-757 THROUGHOUT THE APPROACH. AT THE TIME OF THE UPSET, THE VERTICAL SEPARATION BETWEEN AIRPLANES WAS 600-1000 FT, AND THE HORIZONTAL SEPARATION WAS DECREASING BELOW 2.6 MI. ONE OF THE CITATION CAPTAIN'S LAST COMMENTS WAS 'ALMOST RAN OVER A SEVEN FIFTY SEVEN.' WINDS WERE 5 KTS.

## Aircraft

- Registration: [N6887Y](https://openairdocs.org/deregistered/N6887Y-1993-05-20), registration cancelled 1993-05-20, S/N 5500293 (OpenAirDocs)
- Reported make and model: CESSNA 550
- Registry model: [Cessna 550](https://openairdocs.org/model/cessna-550) (registry code 2076604) (OpenAirDocs)
- Category: Airplane
- Serial number: 550-0293
- Airframe hours: 5275
- Engines: P&W JT15D-4 2500 lbs thrust turbo fan
- Damage: Destroyed
- Fire: On-Ground
- Flight: Public aircraft, Public use
- Operator: Department Of Energy (Wapa)
- Registered owner: Department Of Energy (Wapa)
- Airworthiness certificate: Standard, Normal
- Last inspection: Continuous airworthiness, November 6, 1992, 45 hours before
- Departed: ATY, WATERTOWN, SD
- Flight plan: IFR
- Airport: BIL, Billings Logan Intl., runway 27R, 10,528 × 150 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 39; commercial, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; toxicology performed; flight hours: 6,200 total, 4,415 in this make and model

## Weather

- Conditions: Visual (VMC), Dusk
- Wind: 350° at 5 knots
- Visibility: 40 statute miles
- Lowest ceiling: none
- Temperature: 1 °F, dew point 5 °F
- Altimeter: 29.00 inHg
- Observed at: BIL, 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 19921218050929A](https://openairdocs.org/incident/19921218050929A), Dec 18, 1992: Cessna 550, Billings, MT, Destroyed, 8 fatal. Landing to close behind landing plane rolled inverted, dived into ground. Pilot last words. Almost ran over a 757.

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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