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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Attributes
ACN	808773
Time
Date	200810
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Person 1
Affiliation	company : air carrier
Function	maintenance : technician
ASRS Report	808773
Events
Anomaly	aircraft equipment problem : critical maintenance problem : improper documentation maintenance problem : improper maintenance non adherence : published procedure non adherence : far
Independent Detector	other other : 1
Resolutory Action	none taken : detected after the fact
Consequence	other
Factors
Maintenance	contributing factor : briefing contributing factor : engineering procedure performance deficiency : installation performance deficiency : scheduled maintenance performance deficiency : repair performance deficiency : non compliance with legal requirements
Supplementary
Problem Areas	Maintenance Human Performance Chart Or Publication Aircraft
Primary Problem	Maintenance Human Performance

Narrative:

We have been doing aft pressure bulkhead t-cap replacements due to them being cracked. Where the engine 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 aircraft. Also; I believe there might be a couple of aircraft that the 5/32 fasteners were put back in inside of the pylon between the upper and lower skins which are accessible but a little difficult to get in. Another mechanic 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 aircraft 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.

Original NASA ASRS Text

Title: 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.

Narrative: 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.

Data retrieved from NASA's ASRS site as of May 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.