Narrative:

My work package included a nose landing gear strut service. I have done strut services on B737 aircraft; but not on md-80's. I looked through my task card and it started off telling me to determine if the strut had only an upper fill valve; or it had both an upper and lower fill valve. The task card didn't provide very specific graphics for this. The strut itself had the usual upper fill valve; and it had a plug where it appeared a lower fill valve should be. This led me to believe that the strut had both the upper and lower fill valve confign. I consulted the mechanic's reference on the front of the task card; and it had a picture showing a check valve where I saw the plug. I was then convinced that a check valve was supposed to go there. I had my lead order one; and I installed it after stores delivered it. I completed the task; and figured I should leave the check valve on the strut because the maintenance manual reference listed on the front of the task card showed it being part of the strut assembly. I didn't realize that the strut on this aircraft was configured slightly different than most; and the check vale was big enough to cause gear retraction difficulty. Callback conversation with reporter revealed the following information: reporter stated this aircraft's nose landing gear has (4) different servicing configurations. Those with a single service schraeder valve at the top of the strut; others with a top valve and lower machined drilled port with service valve installed; some with top valve and only a plug installed at the lower service port and others with only a service valve at the strut top without any port hole on the lower side. Reporter noted his task card did not differentiate the fact that some struts with a lower side service port were machined drilled with a downward angled thread as opposed to most struts with an upward angled threaded section. Installing a service valve in the lower port with the downward angle threading would not provide enough clearance for the nose gear to fully retract into the wheel well due to contact with drag brace and beam. Post service gear swings are not required even after full strut service. Instead a deferral is created to later check the strut extension is within limits. Reporter also stated the job card and references; including diagrams; are being revised to reflect the upward and downward angled ports and when the lower service port should or should not; have a service valve.

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Original NASA ASRS Text

Title: AN MD-80 ACFT HAD A NOSE LNDG GEAR STRUT SERVICE AND A LOWER FILL VALVE INSTALLED. STRUT NOT CONFIGURED FOR THIS VALVE.

Narrative: MY WORK PACKAGE INCLUDED A NOSE LNDG GEAR STRUT SVC. I HAVE DONE STRUT SVCS ON B737 ACFT; BUT NOT ON MD-80'S. I LOOKED THROUGH MY TASK CARD AND IT STARTED OFF TELLING ME TO DETERMINE IF THE STRUT HAD ONLY AN UPPER FILL VALVE; OR IT HAD BOTH AN UPPER AND LOWER FILL VALVE. THE TASK CARD DIDN'T PROVIDE VERY SPECIFIC GRAPHICS FOR THIS. THE STRUT ITSELF HAD THE USUAL UPPER FILL VALVE; AND IT HAD A PLUG WHERE IT APPEARED A LOWER FILL VALVE SHOULD BE. THIS LED ME TO BELIEVE THAT THE STRUT HAD BOTH THE UPPER AND LOWER FILL VALVE CONFIGN. I CONSULTED THE MECH'S REF ON THE FRONT OF THE TASK CARD; AND IT HAD A PICTURE SHOWING A CHK VALVE WHERE I SAW THE PLUG. I WAS THEN CONVINCED THAT A CHK VALVE WAS SUPPOSED TO GO THERE. I HAD MY LEAD ORDER ONE; AND I INSTALLED IT AFTER STORES DELIVERED IT. I COMPLETED THE TASK; AND FIGURED I SHOULD LEAVE THE CHK VALVE ON THE STRUT BECAUSE THE MAINT MANUAL REF LISTED ON THE FRONT OF THE TASK CARD SHOWED IT BEING PART OF THE STRUT ASSEMBLY. I DIDN'T REALIZE THAT THE STRUT ON THIS ACFT WAS CONFIGURED SLIGHTLY DIFFERENT THAN MOST; AND THE CHK VALE WAS BIG ENOUGH TO CAUSE GEAR RETRACTION DIFFICULTY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED THIS AIRCRAFT'S NOSE LANDING GEAR HAS (4) DIFFERENT SERVICING CONFIGURATIONS. THOSE WITH A SINGLE SERVICE SCHRAEDER VALVE AT THE TOP OF THE STRUT; OTHERS WITH A TOP VALVE AND LOWER MACHINED DRILLED PORT WITH SERVICE VALVE INSTALLED; SOME WITH TOP VALVE AND ONLY A PLUG INSTALLED AT THE LOWER SERVICE PORT AND OTHERS WITH ONLY A SERVICE VALVE AT THE STRUT TOP WITHOUT ANY PORT HOLE ON THE LOWER SIDE. REPORTER NOTED HIS TASK CARD DID NOT DIFFERENTIATE THE FACT THAT SOME STRUTS WITH A LOWER SIDE SERVICE PORT WERE MACHINED DRILLED WITH A DOWNWARD ANGLED THREAD AS OPPOSED TO MOST STRUTS WITH AN UPWARD ANGLED THREADED SECTION. INSTALLING A SERVICE VALVE IN THE LOWER PORT WITH THE DOWNWARD ANGLE THREADING WOULD NOT PROVIDE ENOUGH CLEARANCE FOR THE NOSE GEAR TO FULLY RETRACT INTO THE WHEEL WELL DUE TO CONTACT WITH DRAG BRACE AND BEAM. POST SERVICE GEAR SWINGS ARE NOT REQUIRED EVEN AFTER FULL STRUT SERVICE. INSTEAD A DEFERRAL IS CREATED TO LATER CHECK THE STRUT EXTENSION IS WITHIN LIMITS. REPORTER ALSO STATED THE JOB CARD AND REFERENCES; INCLUDING DIAGRAMS; ARE BEING REVISED TO REFLECT THE UPWARD AND DOWNWARD ANGLED PORTS AND WHEN THE LOWER SERVICE PORT SHOULD OR SHOULD NOT; HAVE A SERVICE VALVE.

Data retrieved from NASA's ASRS site as of January 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.