Aviation Accident Summaries

Aviation Accident Summary ANC02IA007

Anchorage, AK, USA

Aircraft #1

N825BX

Douglas DC-8-71F

Analysis

The crew of Douglas DC-8-71F airplane reported a partial flight control malfunction during takeoff. The captain reported that just after the airplane became airborne, the airplane rolled hard to the left. He said that he had to apply full right aileron control, in conjunction with right rudder, to keep the airplane from continuing to roll to the left. The crew immediately declared an in-flight emergency, returned to the airport using left turns only, and made an emergency, high speed landing, without the use of any wing flaps. After landing, the flight crew discovered that the left wing outboard spoiler had deployed just after takeoff. A postincident inspection revealed a broken outboard left wing spoiler retraction cable. An NTSB Metallurgist reported that a magnified optical examination of the broken cable revealed that the area adjacent to the fracture site was severely worn, and reduced in size. He added that many individual wire strands were worn to a knife-edge. The remaining broken strands appeared typical of overstress separations, with no indication of external corrosion. Currently, the subject cable is considered to be an "on condition" component, and has no required life limit assigned. In response to this incident the airplane's manufacture sent a safety notice to all DC-8 operators. In the notice, the manufacturer recommends that all operators review their maintenance procedures with respect to the scheduled inspection of all aircraft cables. A special emphasis was placed on the proper cable condition and cable routing.

Factual Information

On December 14, 2001, about 0515 Alaska standard time, the flight crew of N825BX, a Douglas DC-8-71F airplane, reported a partial flight control malfunction during takeoff from the Ted Stevens International Airport, Anchorage, Alaska. The airplane was being operated as an instrument (IFR) cross-country cargo flight under Title 14, CFR Part 121 supplemental, by Air Transport International, Inc., as Flight 8101. There were no injuries to the two pilots, or the one flight engineer aboard. Visual meteorological conditions prevailed, and an instrument flight plan had been filed. The flight originated about 0515, from the Ted Stevens International Airport, and was en route to the Seattle-Tacoma International Airport, Seattle, Washington. The captain reported to his company maintenance personnel that during takeoff on runway 32, just after the airplane became airborne, the airplane rolled hard to the left. He said that he had to apply full right aileron control, in conjunction with right rudder, to keep the airplane from continuing to roll to the left. The crew immediately declared an in-flight emergency, returned to the Ted Stevens International Airport using left turns only, and made an emergency, high speed landing on runway 6L, without the use of any wing flaps. After landing, the flight crew discovered that the left wing outboard spoiler had deployed just after takeoff. A postincident maintenance inspection revealed a broken outboard left wing spoiler retraction cable. The cable was removed from the incident airplane and sent to the National Transportation Safety Boards Materials Laboratory in Washington, D.C. for examination. A Senior Safety Board Metallurgist reported that a magnified optical examination of the fractured cable revealed no indications of external corrosion. He added that the area adjacent to the fracture site on the cable was severely worn and reduced in size. Many of the individual wire strands were worn to a knife-edge. The remaining cross sections appeared typical of overstress separations. The nature of the wear indicated that it was from both internal (wire to wire) contact, and by external contact with another body. He reported that a majority of the damage was internal wear. Currently, the subject cable is considered to be an "on condition" component, and has no required life limit assigned. On July 19, 2002, Boeing Aircraft Company of Long Beach, California, sent a safety notice to all DC-8 operators, and Boeing Field Service bases. In the notice, Boeing recommends that all operators review their maintenance procedures with respect to the scheduled inspection of all aircraft cables. A special emphasis was placed on the proper cable condition and cable routing.

Probable Cause and Findings

The asymmetrical activation of the left wing spoiler due to a broken retraction cable during takeoff. A factor associated with the incident was the operator's inadequate inspection of the cable.

 

Source: NTSB Aviation Accident Database

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