Narrative:

At ZZZ maintenance base; I was the assigned inspector on a crj-900; responsible for performing inspection duties on a job card for the functional check of the elevator control cable tension. Because of a shortage of maintenance personnel on that night; I was asked to train technician 'X' in performing the job card. It was a difficult responsibility because I was never sure if he understood all of the questions I would ask him since this was the first time he had performed this job card. There was an uneasiness inside me during the entire night that almost became distractive. As we worked our way through the job card; it became apparent that technician 'X' was going to have to work overtime. He asked for permission and received it. We continued with the job card and prepared to take the elevator cable tensions as required by the job card. The P-1 pins were installed at this time. I was becoming increasingly tired at that point. Technician 'X' asked me if we needed to install rig pin P-2. Because of what I had observed on an earlier occasion I said 'no'. I took the tensions in the aft compartment as instructed by the job card and found all tensions to be within limits except one cable and it was two pounds low. I wanted it to be within specifications so I made the decision to give the turnbuckle a quarter of a turn. I wasn't sure that technician 'X' understood me but he said yes; he did. I was standing there but could not see him working. As he turned the turnbuckle; I heard him say something. I ask him to repeat what he said and he said the cable had 'gotten looser'. Because of my lack of knowledge of the crj-900 elevator system; I determined that he loosened the turnbuckle. I told him to tighten the turnbuckle. He did and brought it up to 60 lbs tension as called out in the job card. I checked all tensions and found them to be within limits. We pulled the P-1 pins. Because of my lack of experience; I did not know how to handle step 11. I should have not signed it off the way I did. I think the reason this event occurred lands on several factors: the time period of the working day. We started the job card very late and we were both tired. There is always pressure to get the job card done and completed on the required shift. A combination of the tiredness and pressure to get the job done I believe contributed to what occurred. Another factor is the language barrier. Sometimes I would get a 'yes' to a question that couldn't have a yes answer. Another factor is my lack of experience and understanding of the elevator system on a crj- 900. I handled this like I did when I was rigging and tensioning lear jets. When the cable loosened; that should have been a red flag for me. Another factor is I really acted as a mechanic and not as an inspector. I believe I kept them separated as necessary but if it wouldn't have been for the shortage of mechanics that night I might have suggested that another trained mechanic might have assisted technician 'X' in his training. Another factor is I had observed on another aircraft that the P-2 pin had not been installed during the process. I think there should be a warning stating what could happen to the elevator system if the P-2 pin is not installed. For example: warning: adjustment of cable tension without proper length rig pin (P2) installed into and completely inserted into the rear quadrant assembly; will cause asymmetrical deflection of left and right elevators. I think that maybe panel 325EL should also be listed in the access part of the job card. I think there should be a statement labeled 6a; stating that panels 325 dl and 325 el should be removed at this time. I think there should be a training class on cable tensions given to all aircraft inspectors who have never performed this job card. This could be at each facility if necessary to cut down on costs.

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Original NASA ASRS Text

Title: A Mechanic and an Inspector report about factors that contributed to their mis-rigging the Elevator Control Cable Tensions on a CRJ-900 aircraft. The Inspector was asked to train the Mechanic in the Tension procedure; but neither had done an actual rig of the -900 Elevator cables before.

Narrative: At ZZZ Maintenance Base; I was the assigned Inspector on a CRJ-900; responsible for performing inspection duties on a Job Card for the Functional Check of the Elevator Control Cable Tension. Because of a shortage of Maintenance personnel on that night; I was asked to train Technician 'X' in performing the Job Card. It was a difficult responsibility because I was never sure if he understood all of the questions I would ask him since this was the first time he had performed this Job Card. There was an uneasiness inside me during the entire night that almost became distractive. As we worked our way through the Job Card; it became apparent that Technician 'X' was going to have to work overtime. He asked for permission and received it. We continued with the Job Card and prepared to take the elevator Cable Tensions as required by the Job Card. The P-1 pins were installed at this time. I was becoming increasingly tired at that point. Technician 'X' asked me if we needed to install rig pin P-2. Because of what I had observed on an earlier occasion I said 'no'. I took the Tensions in the aft compartment as instructed by the Job Card and found all Tensions to be within limits except one cable and it was two pounds low. I wanted it to be within specifications so I made the decision to give the Turnbuckle a quarter of a turn. I wasn't sure that Technician 'X' understood me but he said yes; he did. I was standing there but could not see him working. As he turned the Turnbuckle; I heard him say something. I ask him to repeat what he said and he said the cable had 'gotten looser'. Because of my lack of knowledge of the CRJ-900 Elevator system; I determined that he loosened the Turnbuckle. I told him to tighten the Turnbuckle. He did and brought it up to 60 lbs tension as called out in the Job Card. I checked all Tensions and found them to be within limits. We pulled the P-1 pins. Because of my lack of experience; I did not know how to handle Step 11. I should have not signed it off the way I did. I think the reason this event occurred lands on several factors: The time period of the working day. We started the Job Card very late and we were both tired. There is always pressure to get the Job Card done and completed on the required shift. A combination of the tiredness and pressure to get the job done I believe contributed to what occurred. Another factor is the language barrier. Sometimes I would get a 'yes' to a question that couldn't have a yes answer. Another factor is my lack of experience and understanding of the Elevator system on a CRJ- 900. I handled this like I did when I was rigging and tensioning Lear Jets. When the cable loosened; that should have been a red flag for me. Another factor is I really acted as a Mechanic and not as an Inspector. I believe I kept them separated as necessary but if it wouldn't have been for the shortage of Mechanics that night I might have suggested that another trained Mechanic might have assisted Technician 'X' in his training. Another factor is I had observed on another aircraft that the P-2 pin had not been installed during the process. I think there should be a warning stating what could happen to the Elevator System if the P-2 pin is not installed. For example: WARNING: adjustment of cable tension without proper length Rig pin (P2) installed into and completely inserted into the rear quadrant assembly; will cause asymmetrical deflection of left and right elevators. I think that maybe Panel 325EL should also be listed in the access part of the Job Card. I think there should be a statement labeled 6a; stating that Panels 325 DL and 325 EL should be removed at this time. I think there should be a Training class on cable tensions given to all Aircraft Inspectors who have never performed this Job Card. This could be at each facility if necessary to cut down on costs.

Data retrieved from NASA's ASRS site as of April 2012 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.