MECHANIC REPORTS THEY HAVE BEEN DOING AFT PRESSURE BULKHEAD T-CAP REPLACEMENTS DUE TO BEING CRACKED ON THEIR MD-80 AIRCRAFT. SAME SIZE FASTENERS WERE REINSTALLED WITH ONLY VERBAL APPROVAL; BUT LATER CONSIDERED UNACCEPTABLE.

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WE HAVE BEEN DOING AFT PRESSURE BULKHEAD T-CAP REPLACEMENTS DUE TO THEM BEING CRACKED. WHERE THE ENG PYLON UPPER AND LOWER SKINS INTERSECT THE T-CAP; THERE ARE 8 FASTENERS THAT LINE UP WITH THE PYLON SKINS AND ARE NEARLY IMPOSSIBLE TO GET IN. WE ASKED ENGINEERING IF WE COULD PUT THE ORIGINAL 5/32 FASTENERS BACK IN THESE LOCATIONS INSTEAD OF ENLARGING TO A 3/16 FASTENER AS STATED IN THE AIRWORTHINESS DIRECTIVE AND SRM AND WAS TOLD THAT WOULD BE OK; SO WE DID ON SEVERAL ACFT. ALSO; I BELIEVE THERE MIGHT BE A COUPLE OF ACFT THAT THE 5/32 FASTENERS WERE PUT BACK IN INSIDE OF THE PYLON BTWN THE UPPER AND LOWER SKINS WHICH ARE ACCESSIBLE BUT A LITTLE DIFFICULT TO GET IN. ANOTHER MECH TALKED TO THE ENGINEER AND HE WAS TOLD THIS PRACTICE WAS UNACCEPTABLE BECAUSE IT DEVIATED FROM THE AIRWORTHINESS DIRECTIVE AND WE ARE NOT ALLOWED TO DO THIS. I AM NOT SURE HOW MANY ACFT THIS INVOLVES; BUT IT COULD BE AS MANY AS 8. ENGINEERING GAVE US DIRECTIONS TO GO BY AND LATER RECANTED DIRECTIONS SAYING HE NEVER TOLD US.