What happened
Shortly after becoming airborne, the crew of a Douglas DC-8-71F experienced a hard roll to the left. To prevent the aircraft from continuing this roll, the captain was forced to apply full right aileron control along with right rudder input. The flight crew declared an in-flight emergency and returned to the airport, performing only left turns during the approach. The aircraft completed an emergency, high-speed landing without the use of wing flaps. Following the landing, the crew identified that the left wing outboard spoiler had deployed immediately after takeoff.
The investigation
A post-incident inspection of the aircraft revealed a broken retraction cable for the outboard left wing spoiler. An NTSB metallurgist performed a magnified optical examination of the fractured cable, finding that the area adjacent to the fracture site was severely worn and reduced in size. The examination showed that many individual wire strands had been worn down to a knife-edge. The remaining strands at the break appeared consistent with overstress separations, and there was no evidence of external corrosion. The cable in question is currently classified as an "on condition" component with no specific life limit.
Findings
- Deployment of the left wing outboard spoiler during takeoff.
- A broken outboard left wing spoiler retraction cable caused by wear and subsequent overstress.