Narrative:
The takeoff warning horn sounded shortly after commencing takeoff from runway 09R. The takeoff was continued as the crew tried to figure out what caused the warning. The horn ceased prior to reaching rotate speed. The stickshaker came on and thrust was added, but the aircraft failed to climb and the captain elected to discontinue the takeoff. The 727 settled back to the macadam shoulder off the right side of the runway and struck a ditch, coming to rest 1100 feet beyond the runway end and 300 feet right of the extended centreline. The flaps had been set at 2deg instead of takeoff range of 5-25 degrees.
PROBABLE CAUSE: "The failure of the crew to abort the takeoff after being warned of an unsafe takeoff condition."
| Status: | Accident investigation report completed and information captured |
| Date: | Thursday 21 March 1968 |
| Time: | 03:53 |
| Type: |  Boeing 727-22C |
| Operator: | United Airlines |
| Registration: | N7425U |
| MSN: | 19200/416 |
| First flight: | 1967-05-25 (10 months) |
| Total airframe hrs: | 2208 |
| Engines: | 3 Pratt & Whitney JT8D-1 |
| Crew: | Fatalities: 0 / Occupants: 3 |
| Passengers: | Fatalities: 0 / Occupants: 0 |
| Total: | Fatalities: 0 / Occupants: 3 |
| Aircraft damage: | Damaged beyond repair |
| Location: | Chicago-O'Hare International Airport, IL (ORD) ( United States of America)
|
| Phase: | Takeoff (TOF) |
| Nature: | Cargo |
| Departure airport: | Chicago-O'Hare International Airport, IL (ORD/KORD), United States of America |
| San Francisco International Airport, CA (SFO/KSFO), United States of America | |
| Flightnumber: | UA9963 |
The takeoff warning horn sounded shortly after commencing takeoff from runway 09R. The takeoff was continued as the crew tried to figure out what caused the warning. The horn ceased prior to reaching rotate speed. The stickshaker came on and thrust was added, but the aircraft failed to climb and the captain elected to discontinue the takeoff. The 727 settled back to the macadam shoulder off the right side of the runway and struck a ditch, coming to rest 1100 feet beyond the runway end and 300 feet right of the extended centreline. The flaps had been set at 2deg instead of takeoff range of 5-25 degrees.
Probable Cause:
PROBABLE CAUSE: "The failure of the crew to abort the takeoff after being warned of an unsafe takeoff condition."
Accident investigation:
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Follow-up / safety actions
Following a recommendation by the NTSB, the FAA reviewed the procedures prescribed in U.S. air carrier's manuals to ensure that takeoffs will be aborted whenever the takeoff warning horn sounds prior to reaching V1, unless there are other overriding factors. NTSB issued 2 Safety Recommendations
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Photos
Map
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 Chicago-O'Hare International Airport, IL to San Francisco International Airport, CA as the crow flies is 2943 km (1840 miles).
Distance from Chicago-O'Hare International Airport, IL to San Francisco International Airport, CA as the crow flies is 2943 km (1840 miles).
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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