Accident Boeing 707-321B N761PA, Monday 28 June 1965
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Date:Monday 28 June 1965
Time:14:13
Type:Silhouette image of generic B703 model; specific model in this crash may look slightly different    
Boeing 707-321B
Owner/operator:Pan American World Airways (Pan Am)
Registration: N761PA
MSN: 18336/270
Year of manufacture:1962
Total airframe hrs:12789 hours
Fatalities:Fatalities: 0 / Occupants: 153
Other fatalities:0
Aircraft damage: Substantial, repaired
Category:Accident
Location:near San Francisco, CA -   United States of America
Phase: Take off
Nature:Passenger - Scheduled
Departure airport:San Francisco International Airport, CA (SFO/KSFO)
Destination airport:Honolulu International Airport, HI (HNL/PHNL)
Investigating agency: CAB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
Pan Am flight 843 experienced an explosive disintegration of the third stage turbine disk of the No. 4 engine. The accident occurred shortly after takeoff from San Francisco, at an altitude of about 800 feet above the ground.
Disintegration of the turbine disk was followed by a fire in the No. 4 engine area and an explosion in the outboard reserve fuel tank. The No. 4 engine and approximately 25 feet of the right outer wing separated from the aircraft.
The fire was extinguished and a successful emergency landing was accomplished at Travis Air Force Base, California, with no injuries to the 143 passengers or 10 crewmembers aboard the flight.

PROBABLE CAUSE: "The failure of the third stage turbine disk. This failure was caused by a transient loss of operating clearance between the third stage turbine disk and the third stage inner sealing ring. This loss of clearance resulted from a combination of improper turbine rotor positioning during engine assembly, the use of serviceable worn parts, and an operating clearance which was less than predicted in design analysis."

Accident investigation:
  
Investigating agency: CAB
Report number: OAK65A0076
Status: Investigation completed
Duration: 1 year and 4 months
Download report: Final report

Sources:

CAB accident report
Life 26.7.1965

Images:


photo (c) Roger Stewart; Travis AFB; 30 June 1965

Revision history:

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