scope:

Description of Driving Event:

The trunnion covers used to support Extra-vehicular activity (EVA) were reportedly altered late in the flow of STS-88 preparations. The modification included the addition of a tether point and changing a part number. The part number was used in the EVA checklist to allow the crew to properly determine on which cover to install each trunnion; the changed part number was not picked up for the checklist. This change resulted in confusion during EVA-2. Additionally, the tether point was not included in the NBL mockups.

While implementing this Lessons Learned, it was further reported the change to the trunnion covers developed out of a fit check done at KSC with a VITT representative from the Crew Office in attendance. Velcro was added to the cover to make it fit better per ECP BHE 1780 (Note: the tether points have been in the design of the trunnion covers since June of 1997 although they were not included in the NBL mockup). Additionally, as part of the coordination on this change, photographs of the before and after covers were taken in the Huntsville shop and sent to Houston. This information further underscores the breakdown in the configuration control processes within the program.)

Root cause: Lack of configuration control processes for changes that do not require Program level change requests.