Incident
The first officer, serving as the flying pilot, detected a right wing heavy condition with roll control difficulties during liftoff. The crew dumped fuel and returned for a landing. Post-landing inspection showed that three of the five spoilers on top of the right wing were fully deployed.
Findings
Mechanics found a general-purpose shop rag lodged in the spoiler control pulley system, jamming it in the deployed position. The pulley area where the rag was found was an open and unprotected area in the center body landing gear wheel well. The center gear doors are normally closed on the ground; however, maintenance personnel can open the doors to work in this area. The doors open and the center landing gear retracts forward into this area during normal operation.
Maintenance Background
The last maintenance completed in this area was two days prior to the incident, when a contract fuel systems repair company opened several lines in that area to check for leaks. Mechanics could not find any rags, so a supervisor brought rags from another hangar. The supervisor was positive that he provided diaper style rags rather than shop style rags. His company only used the diaper style rag because it was more absorbent than a regular shop rag. A mechanic for the carrier said they normally used colored general-purpose shop towels. They occasionally used white terrycloth towels. The airplane completed nine flights through various line stations prior to the mishap. On a walk around inspection, mechanics do not normally open the wheel well doors and look at the spoiler pulley system.