Narrative:

While accomplishing engineering change order X, section involving torque values came up. It has always been my perception that if a nut was accessible that it should be torqued by the nut. After determining that the nut was accessible but difficult to torque, we continued. We torqued the nuts to 215 inch-pounds but brought to the attention of the supervisor if there was an appropriate value we could torque the bolts since torqueing the nuts was difficult. Supervisor stated that the srm states that a 10% increase in torque value would be sufficient for the bolt. As we torqued the nuts to 215 inch-pounds, we tested the bolts at 160 inch-pounds and they did not move, leading us to believe that 10% was incorrect. We finished torqueing all the nuts to 215 inch-pounds. The following day, engineering stated that the bolts should have been torqued in what I believe to be the proper way of torqueing. However, it may have been incorrect, in this task, due to unclr torqueing procedures. Now my feeling is that if the bolts were to be torqued instead of the nuts, that we may have over-torqued the bolts. What I would like to see is a better or clrer procedure of what is to be torqued, the bolt head or nut, so that there will not be a misunderstanding involving this engineering change order.

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Original NASA ASRS Text

Title: WHILE ACCOMPLISHING AN ENGINEERING CHANGE ORDER TO THE FAN BLADE STOPS ON A B737-500, THE PAPERWORK INDICATED NO TORQUE VALUES. THE BOLTS MAY HAVE BEEN OVER TORQUED.

Narrative: WHILE ACCOMPLISHING ENGINEERING CHANGE ORDER X, SECTION INVOLVING TORQUE VALUES CAME UP. IT HAS ALWAYS BEEN MY PERCEPTION THAT IF A NUT WAS ACCESSIBLE THAT IT SHOULD BE TORQUED BY THE NUT. AFTER DETERMINING THAT THE NUT WAS ACCESSIBLE BUT DIFFICULT TO TORQUE, WE CONTINUED. WE TORQUED THE NUTS TO 215 INCH-LBS BUT BROUGHT TO THE ATTN OF THE SUPVR IF THERE WAS AN APPROPRIATE VALUE WE COULD TORQUE THE BOLTS SINCE TORQUEING THE NUTS WAS DIFFICULT. SUPVR STATED THAT THE SRM STATES THAT A 10% INCREASE IN TORQUE VALUE WOULD BE SUFFICIENT FOR THE BOLT. AS WE TORQUED THE NUTS TO 215 INCH-LBS, WE TESTED THE BOLTS AT 160 INCH-LBS AND THEY DID NOT MOVE, LEADING US TO BELIEVE THAT 10% WAS INCORRECT. WE FINISHED TORQUEING ALL THE NUTS TO 215 INCH-LBS. THE FOLLOWING DAY, ENGINEERING STATED THAT THE BOLTS SHOULD HAVE BEEN TORQUED IN WHAT I BELIEVE TO BE THE PROPER WAY OF TORQUEING. HOWEVER, IT MAY HAVE BEEN INCORRECT, IN THIS TASK, DUE TO UNCLR TORQUEING PROCS. NOW MY FEELING IS THAT IF THE BOLTS WERE TO BE TORQUED INSTEAD OF THE NUTS, THAT WE MAY HAVE OVER-TORQUED THE BOLTS. WHAT I WOULD LIKE TO SEE IS A BETTER OR CLRER PROC OF WHAT IS TO BE TORQUED, THE BOLT HEAD OR NUT, SO THAT THERE WILL NOT BE A MISUNDERSTANDING INVOLVING THIS ENGINEERING CHANGE ORDER.

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.