An MD87 during a heavy maintenance check it was found the horizontal stabilizer jackscrew acme nut could be installed 180 degrees off with stop pad aft.

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Attributes
ACN	519443
Time
Date	200108
Day	Sun
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl bound lower : 0
Aircraft 1
Controlling Facilities	tower : zzz.tower
Operator	common carrier : air carrier
Make Model Name	MD-87
Operating Under FAR Part	Part 121
Flight Phase	ground : maintenance
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	maintenance : technician
Qualification	technician : powerplant technician : airframe
ASRS Report	519443
Person 2
Affiliation	company : air carrier
Function	maintenance : technician
Events
Anomaly	aircraft equipment problem : critical maintenance problem : improper maintenance maintenance problem : improper documentation non adherence : published procedure non adherence : far
Independent Detector	other other : person 1
Resolutory Action	none taken : detected after the fact
Consequence	other other
Factors
Maintenance	contributing factor : work cards contributing factor : manuals performance deficiency : testing performance deficiency : scheduled maintenance performance deficiency : inspection performance deficiency : installation
Supplementary
Problem Areas	Maintenance Human Performance Chart Or Publication Aircraft
Primary Problem	Chart Or Publication
Situations
Publication	Maint Manual Job Card

Narrative:

Jackscrew acme nut. On airplane in dock, ask to remove jackscrew assembly. For structure repair. After repair was complete, was assigned to reinstall jackscrew assembly. Upon installation noticed that acme nut or gimbal could be installed 180 degrees from proper position. In august of 2000 asked to go on a field trip to ZZZ for jackscrew assembly replacement. When installing jackscrew assembly per M/M MD87 we may have overlooked the proper position of acme nut. Callback conversation with reporter revealed the following information: the reporter stated the airplane worked on field service was rechecked and found the jackscrew installation correct. The reporter said the job card does not emphasize or underline the step to install the acme nut with the stop pad facing forward. The reporter stated the importance of this step being correct cannot be overstated. The reporter said with the stop pad facing aft the dimensions of the jackscrew are changed which changes the travel of the horizontal stabilizer.

Original NASA ASRS Text

Title: AN MD87 DURING A HEAVY MAINT CHECK IT WAS FOUND THE HORIZONTAL STABILIZER JACKSCREW ACME NUT COULD BE INSTALLED 180 DEGS OFF WITH STOP PAD AFT.

Narrative: JACKSCREW ACME NUT. ON AIRPLANE IN DOCK, ASK TO REMOVE JACKSCREW ASSEMBLY. FOR STRUCTURE REPAIR. AFTER REPAIR WAS COMPLETE, WAS ASSIGNED TO REINSTALL JACKSCREW ASSEMBLY. UPON INSTALLATION NOTICED THAT ACME NUT OR GIMBAL COULD BE INSTALLED 180 DEGS FROM PROPER POS. IN AUGUST OF 2000 ASKED TO GO ON A FIELD TRIP TO ZZZ FOR JACKSCREW ASSEMBLY REPLACEMENT. WHEN INSTALLING JACKSCREW ASSEMBLY PER M/M MD87 WE MAY HAVE OVERLOOKED THE PROPER POSITION OF ACME NUT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE AIRPLANE WORKED ON FIELD SERVICE WAS RECHECKED AND FOUND THE JACKSCREW INSTALLATION CORRECT. THE RPTR SAID THE JOB CARD DOES NOT EMPHASIZE OR UNDERLINE THE STEP TO INSTALL THE ACME NUT WITH THE STOP PAD FACING FORWARD. THE RPTR STATED THE IMPORTANCE OF THIS STEP BEING CORRECT CANNOT BE OVERSTATED. THE RPTR SAID WITH THE STOP PAD FACING AFT THE DIMENSIONS OF THE JACKSCREW ARE CHANGED WHICH CHANGES THE TRAVEL OF THE HORIZONTAL STABILIZER.

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.