Narrative:

The PIC called in from smf with a mechanical discrepancy. During a flight attendant crew change there, an oncoming flight attendant noticed the aft pbe unit had an extended vsi, and further, had a 'spongy' feel to it, and did not meet svcability requirements per procedures noted on the unit's placard. Our MEL page (dated sep/xx/94) states that any in excess of those required by far (4) may be inoperative. As we only have 4 installed, all 4 are required. Our MEL also states that the vsi may be protruding (it was) and/or 1 (or both) tamper evident seals may be broken or missing provided the pbe is svcable as determined by the pbe check procedure placard affixed to the unit itself, which the flight attendant stated wasn't the case. Our MEL also makes reference to a maintenance department document (mpd 127), which is published separately, and is not readily available to line flcs. I initiated a 3-WAY phone conversation between myself, the PIC, and the maintenance controller, and the maintenance controller also referred to the mpd 127. I insisted that he facsimile me a copy, which he did *(pages 1 and 2), and I also faxed a copy to the PIC at smf. One of the mpd 127 pages was dated nov.xx.94 (subsequent to the MEL page), and the change bar on this newer page mentioned that a 'spongy' pbe must be replaced within 36 hours of discovery. On this basis, the PIC and I concurred on validity of the MEL item deferral, and the flight operated from smf-lax-las. A new pbe was installed at las, and the logbook cleared. Follow-up with technical support staff a few days later indicated quite a bit of confusion, mainly over which document (MEL or mpd 127) takes precedence, and whether a 'spongy' pbe is actually a svcable one, and thus legal for dispatch. The mpd 127 also had a 3RD and 4TH page (not faxed at the time of the original incident) and it mentions that a 'hard' pbe is svcable, thus one could reasonably conclude that a 'non- hard' (ie, spongy) pbe is not svcable. If true, this was not a legal deferral, thus this report. In closing, my opinion is that sits such as these could be minimized if airline management would word and otherwise construct operational manuals to be as specific as possible, rather than to imbed 'flexibility' that can be interpreted far too liberally. Additionally, all applicable information should be included into the line operating manual (MEL, in this case) rather than referenced to more obscure manuals that are not immediately available to PIC's and dispatchers.

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Original NASA ASRS Text

Title: MLG HAS PBE EQUIP PROB WHICH IS MEL'ED. DISPATCH LATER FINDS THIS WAS NOT LEGAL.

Narrative: THE PIC CALLED IN FROM SMF WITH A MECHANICAL DISCREPANCY. DURING A FLT ATTENDANT CREW CHANGE THERE, AN ONCOMING FLT ATTENDANT NOTICED THE AFT PBE UNIT HAD AN EXTENDED VSI, AND FURTHER, HAD A 'SPONGY' FEEL TO IT, AND DID NOT MEET SVCABILITY REQUIREMENTS PER PROCS NOTED ON THE UNIT'S PLACARD. OUR MEL PAGE (DATED SEP/XX/94) STATES THAT ANY IN EXCESS OF THOSE REQUIRED BY FAR (4) MAY BE INOP. AS WE ONLY HAVE 4 INSTALLED, ALL 4 ARE REQUIRED. OUR MEL ALSO STATES THAT THE VSI MAY BE PROTRUDING (IT WAS) AND/OR 1 (OR BOTH) TAMPER EVIDENT SEALS MAY BE BROKEN OR MISSING PROVIDED THE PBE IS SVCABLE AS DETERMINED BY THE PBE CHK PROC PLACARD AFFIXED TO THE UNIT ITSELF, WHICH THE FLT ATTENDANT STATED WASN'T THE CASE. OUR MEL ALSO MAKES REF TO A MAINT DEPT DOCUMENT (MPD 127), WHICH IS PUBLISHED SEPARATELY, AND IS NOT READILY AVAILABLE TO LINE FLCS. I INITIATED A 3-WAY PHONE CONVERSATION BTWN MYSELF, THE PIC, AND THE MAINT CTLR, AND THE MAINT CTLR ALSO REFERRED TO THE MPD 127. I INSISTED THAT HE FAX ME A COPY, WHICH HE DID *(PAGES 1 AND 2), AND I ALSO FAXED A COPY TO THE PIC AT SMF. ONE OF THE MPD 127 PAGES WAS DATED NOV.XX.94 (SUBSEQUENT TO THE MEL PAGE), AND THE CHANGE BAR ON THIS NEWER PAGE MENTIONED THAT A 'SPONGY' PBE MUST BE REPLACED WITHIN 36 HRS OF DISCOVERY. ON THIS BASIS, THE PIC AND I CONCURRED ON VALIDITY OF THE MEL ITEM DEFERRAL, AND THE FLT OPERATED FROM SMF-LAX-LAS. A NEW PBE WAS INSTALLED AT LAS, AND THE LOGBOOK CLRED. FOLLOW-UP WITH TECHNICAL SUPPORT STAFF A FEW DAYS LATER INDICATED QUITE A BIT OF CONFUSION, MAINLY OVER WHICH DOCUMENT (MEL OR MPD 127) TAKES PRECEDENCE, AND WHETHER A 'SPONGY' PBE IS ACTUALLY A SVCABLE ONE, AND THUS LEGAL FOR DISPATCH. THE MPD 127 ALSO HAD A 3RD AND 4TH PAGE (NOT FAXED AT THE TIME OF THE ORIGINAL INCIDENT) AND IT MENTIONS THAT A 'HARD' PBE IS SVCABLE, THUS ONE COULD REASONABLY CONCLUDE THAT A 'NON- HARD' (IE, SPONGY) PBE IS NOT SVCABLE. IF TRUE, THIS WAS NOT A LEGAL DEFERRAL, THUS THIS RPT. IN CLOSING, MY OPINION IS THAT SITS SUCH AS THESE COULD BE MINIMIZED IF AIRLINE MGMNT WOULD WORD AND OTHERWISE CONSTRUCT OPERATIONAL MANUALS TO BE AS SPECIFIC AS POSSIBLE, RATHER THAN TO IMBED 'FLEXIBILITY' THAT CAN BE INTERPRETED FAR TOO LIBERALLY. ADDITIONALLY, ALL APPLICABLE INFO SHOULD BE INCLUDED INTO THE LINE OPERATING MANUAL (MEL, IN THIS CASE) RATHER THAN REFED TO MORE OBSCURE MANUALS THAT ARE NOT IMMEDIATELY AVAILABLE TO PIC'S AND DISPATCHERS.

Data retrieved from NASA's ASRS site as of July 2007 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.