Narrative:

On aug/xx/98 I was working overnight maintenance on air carrier aircraft xyz. This aircraft had MEL issued on the right thrust reverser accumulator low light. Pilot complaint was that accumulator low light came on in-flight with right engine hydrolock pump in the low position. Light extinguished when right engine hydrolock pump switch was positioned too high. This is a common complaint with the MD80 aircraft when the accumulator is low on pressure. Upon investigation, I found the accumulator pressure at 700 psi. I svced the accumulator with nitrogen to 1000 psi which is the operating pressure. After checking for leaks at the schrader valve and waiting a period of time to see if the accumulator was leaking through the diaphragm, I proceeded to the cockpit to run the right engine at idle and perform a check of the accumulator with the engine hydrolock pump switch. The light checked good in the high and low position of the hydrolock pump switch and felt no further action was required to clear this MEL. During and after engine run, I looked at the throttle handle to see if the reverser handle was secured and it did not appear that it was. The original complaint was for the accumulator low light and not for the reverser operation, therefore, I did not deploy the reverser during engine run or statically. Also, the MEL reflected this by the air traffic area that was issued, chapter xx not yy. The flight departed for XXX at XA35 flight yyz from ZZZ. While in-flight, the flight crew also did not notice any abnormalities with the right engine throttle handle till they landed and the right engine thrust reverser handle would not deploy. Upon close inspection of the reverse handle by XXX maintenance, it was noted that the handle was secured with safety wire in a manner that was not readily noticeable. I feel this situation could have been avoided if there was some visible means of detection on the reverser handle or a placard on the instrument panel bringing attention to this situation. Callback conversation with reporter revealed the following information: the reporter stated the MEL in chapters xx and yy requires rendering the thrust reverser inoperative when a reverser accumulator low pressure warning light is illuminated. The reporter said the procedure calls for safety wiring the thrust lever (throttle) in the forward thrust position. The reporter said the thrust reverser was not operated when the engine was run to check the accumulator and the wire on the thrust lever was not visible. The reporter stated the MEL does not require a placard on the throttle, reverser indication lights or any other cockpit panel. The reporter said the FAA is involved and the air carrier is now in the process of rewriting the MEL special procedures to require cockpit placards. The reporter stated the reverser accumulators are a recurring problem losing the nitrogen pressure charge.

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Original NASA ASRS Text

Title: AN MD80 WAS DISPATCHED WITH A CLRED DEFERRED ITEM ON THE R THRUST REVERSER SYS BUT THE THRUST REVERSER WAS NOT MADE OPERATIONAL DUE TO THE THRUST LEVER WIRED TO THE INOP POS.

Narrative: ON AUG/XX/98 I WAS WORKING OVERNIGHT MAINT ON ACR ACFT XYZ. THIS ACFT HAD MEL ISSUED ON THE R THRUST REVERSER ACCUMULATOR LOW LIGHT. PLT COMPLAINT WAS THAT ACCUMULATOR LOW LIGHT CAME ON INFLT WITH R ENG HYDROLOCK PUMP IN THE LOW POS. LIGHT EXTINGUISHED WHEN R ENG HYDROLOCK PUMP SWITCH WAS POSITIONED TOO HIGH. THIS IS A COMMON COMPLAINT WITH THE MD80 ACFT WHEN THE ACCUMULATOR IS LOW ON PRESSURE. UPON INVESTIGATION, I FOUND THE ACCUMULATOR PRESSURE AT 700 PSI. I SVCED THE ACCUMULATOR WITH NITROGEN TO 1000 PSI WHICH IS THE OPERATING PRESSURE. AFTER CHKING FOR LEAKS AT THE SCHRADER VALVE AND WAITING A PERIOD OF TIME TO SEE IF THE ACCUMULATOR WAS LEAKING THROUGH THE DIAPHRAGM, I PROCEEDED TO THE COCKPIT TO RUN THE R ENG AT IDLE AND PERFORM A CHK OF THE ACCUMULATOR WITH THE ENG HYDROLOCK PUMP SWITCH. THE LIGHT CHKED GOOD IN THE HIGH AND LOW POS OF THE HYDROLOCK PUMP SWITCH AND FELT NO FURTHER ACTION WAS REQUIRED TO CLR THIS MEL. DURING AND AFTER ENG RUN, I LOOKED AT THE THROTTLE HANDLE TO SEE IF THE REVERSER HANDLE WAS SECURED AND IT DID NOT APPEAR THAT IT WAS. THE ORIGINAL COMPLAINT WAS FOR THE ACCUMULATOR LOW LIGHT AND NOT FOR THE REVERSER OP, THEREFORE, I DID NOT DEPLOY THE REVERSER DURING ENG RUN OR STATICALLY. ALSO, THE MEL REFLECTED THIS BY THE ATA THAT WAS ISSUED, CHAPTER XX NOT YY. THE FLT DEPARTED FOR XXX AT XA35 FLT YYZ FROM ZZZ. WHILE INFLT, THE FLC ALSO DID NOT NOTICE ANY ABNORMALITIES WITH THE R ENG THROTTLE HANDLE TILL THEY LANDED AND THE R ENG THRUST REVERSER HANDLE WOULD NOT DEPLOY. UPON CLOSE INSPECTION OF THE REVERSE HANDLE BY XXX MAINT, IT WAS NOTED THAT THE HANDLE WAS SECURED WITH SAFETY WIRE IN A MANNER THAT WAS NOT READILY NOTICEABLE. I FEEL THIS SIT COULD HAVE BEEN AVOIDED IF THERE WAS SOME VISIBLE MEANS OF DETECTION ON THE REVERSER HANDLE OR A PLACARD ON THE INST PANEL BRINGING ATTN TO THIS SIT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE MEL IN CHAPTERS XX AND YY REQUIRES RENDERING THE THRUST REVERSER INOP WHEN A REVERSER ACCUMULATOR LOW PRESSURE WARNING LIGHT IS ILLUMINATED. THE RPTR SAID THE PROC CALLS FOR SAFETY WIRING THE THRUST LEVER (THROTTLE) IN THE FORWARD THRUST POS. THE RPTR SAID THE THRUST REVERSER WAS NOT OPERATED WHEN THE ENG WAS RUN TO CHK THE ACCUMULATOR AND THE WIRE ON THE THRUST LEVER WAS NOT VISIBLE. THE RPTR STATED THE MEL DOES NOT REQUIRE A PLACARD ON THE THROTTLE, REVERSER INDICATION LIGHTS OR ANY OTHER COCKPIT PANEL. THE RPTR SAID THE FAA IS INVOLVED AND THE ACR IS NOW IN THE PROCESS OF REWRITING THE MEL SPECIAL PROCS TO REQUIRE COCKPIT PLACARDS. THE RPTR STATED THE REVERSER ACCUMULATORS ARE A RECURRING PROB LOSING THE NITROGEN PRESSURE CHARGE.

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.