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Last updated: 7 December 2021
Date:Friday 24 August 1984
Type:Silhouette image of generic BE99 model; specific model in this crash may look slightly different
Beechcraft C99 Commuter
Operator:Wings West Airlines
Registration: N6399U
MSN: U-187
First flight: 1982
Engines: 2 Pratt & Whitney Canada PT6A-36
Crew:Fatalities: 2 / Occupants: 2
Passengers:Fatalities: 13 / Occupants: 13
Total:Fatalities: 15 / Occupants: 15
Collision casualties:Fatalities: 2
Aircraft damage: Destroyed
Aircraft fate: Written off (damaged beyond repair)
Location:11 km (6.9 mls) W of San Luis Obispo, CA (   United States of America)
Phase: En route (ENR)
Nature:Domestic Scheduled Passenger
Departure airport:San Luis Obispo-County Airport, CA (SBP/KSBP), United States of America
Destination airport:San Francisco International Airport, CA (SFO/KSFO), United States of America
Flightnumber: 628
Wings West Airlines Flight 628, a commuter flight, departed Los Angeles for San Francisco, with scheduled en route stops at Santa Maria and San Luis Obispo. At 11:10, Flight 628 left the gate at San Luis Obispo. The weather at the time was essentially clear and the visibility was 15 miles. At 11:16, after taking off from runway 29, Flight 628 called the Los Angeles ARTCC and reported that it was climbing through 2,700 feet 'IFR to San Francisco.' At 11:17:23, the Los Angeles ARTCC’s radar controller cleared Flight 628 to the San Francisco airport, as filed, to climb and maintain 7,000 feet. At 11:17:38 the aircraft collided head-on with Rockwell Commander N112SM at 3,400 feet. This single-engined aircraft had departed Paso Robles Airport on a training flight with two pilots on board. Nll2SM was flying in visual meteorological conditions and under VFR in the vicinity of the San Luis Obispo Airport just before the collision.

Probable Cause:

PROBABLE CAUSE: "The failure of the pilots of both aircraft to follow the recommended communications and traffic advisory practices for uncontrolled airports contained in the Airman’s Information Manual to alert each other to their presence and to enhance the controller’s ability to provide timely traffic advisories.
Underlying the accident were the physiological limitations of human vision and reaction time. Also underlying the accident was the short time available to the controller to detect and appraise radar data and to issue a safety advisory. Contributing to the accident was the Wings West Airlines policy which
required its pilots to tune one radio to the company frequency at all times."

Accident investigation:
Investigating agency: NTSB
Status: Investigation completed
Duration: 1 year
Accident number: NTSB/AAR-85-07
Download report: Final report

» NTSB/AAR-85/07
» Reasonable Doubt in the Matter of the Probable Cause of Accident Involving Wings West Airlines, Inc., Beech C99, N6399U, and Aesthetech, Inc., Rockwell Commander 112TC, N112SM, near San Luis Obispo, California on August 24, 1984 / Thomas Lusch

Follow-up / safety actions

NTSB issued 13 Safety Recommendations

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This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path.
Distance from San Luis Obispo-County Airport, CA to San Francisco International Airport, CA as the crow flies is 305 km (191 miles).
Accident location: Exact; as reported in the official accident report.

This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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Beech 99

  • 239 built
  • 21st loss
  • 11th fatal accident
  • 2nd worst accident (at the time)
  • 3rd worst accident (currently)
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