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Orbiter Body Flap Cove Refurbishment

Problem: Body flap cove structure incurs significant corrosion and turnaround repair costs. Evaluation of corrosion mechanisms shows several contributors: deterioration of corrosion inhibiting primer because of age and operational wear on rub plate. Presence of galvanic couples through various dissimilar metals. Exposure to corrosive environment. Turnaround ops damage caused by personnel activity in body flap cove area when covers removed.
Solution: Refurbishment program eliminates corrosion. Aft fuselage: Titanium BF attach fittings. Remove, inspect and prime. Provide RTV fillet between fitting and aluminum aft fuselage frame. Replace aluminum rivets with A286 Rivets. Strip Koropon from aft fuselage stub (media blasting), reprime and apply RTV polyurethane top coat (body flap assy removed). Rub plate mod: machine rub surface. Hot bond .020 CRES doubler to surface as a scuff plate to eliminate galvanic couple. Wear test will be conducted to verify seal life. Body flap assy. Remove chain seals and accordion seals. Clean and inspect body flap interior (OMRSD V30GA0.060) - Rework as required. Hot bond acreage doublers over thin face sheet honeycomb in bottom of cove. Reprime and apply RTV in lower area of cove, covering acreage doublers.

Apply polyurethane top coat in remaining AL area--including forward face of spar, ribs and inboard surface of upper skin. Damage reduction. Produce "shop aid" body flap covers - 4 sets of 13 covers. Similar to method used to protect boron/aluminum tubes in midbody, soft plastic but rigid. More durable than plain "elephant hide" covers. Job card for installation and removal ensures coverage of damage prone areas at all times when cove is open.

Initial Operation Date: Phase II Upgrade
OV-102, J3;
OV-103, F24;
OV-104, J2;
OV-105, J2.
Technology Goal: Minimum weight and CG impact. Modification is straightforward approach. Will protect body and flap associated elements and reduce rate of deterioration and potential component damage for vehicle life.
Goals Supported: 1) Fly Safely
2) Meet the Manifest
3) Improve Supportability
4) Reduce Cost

Curator: Kim Dismukes | Responsible NASA Official: John Ira Petty | Updated: 04/07/2002
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