Narrative:

A dhc-8-100 arrived in the morning with a pilot write-up of the aileron controls feeling a bit rough. My supervisor advised me to check tensions within the system. I took (cable) readings at the left-hand (left/H) rear spar and found them to be a bit low. Prior to tightening (cables) to proper tensions; my supervisor also advised me to check for roughness in the terminating quadrant in the left/H wing.I slackened the cable enough to disconnect the cable from the quadrant; to spin the quadrant by hand and check for worn or migrating bearings. The quadrant checked out fine and the cable was reattached and tensioned to the proper level. The night shift ended up changing the right-hand (right/H) aileron terminating quadrant and the next morning it departed on an test flight.upon return from the test flight; the controls were still found to be a little rough and further troubleshooting commenced. A fellow mechanic; mr. X; found the left/H aileron rear spar lower cable misrouted. Reference illustrated parts catalog (ipc) 27-12-00. The lower cable was found to be running outside and against the pulley guard (item # 440). After routing the cable on the correct side of the pulley guard; the ailerons worked properly.afterwards the question came about as to whether or not I caused the misrouting of the cable during my rigging procedures and I replied that it was unlikely. Granted; I should have been able to diagnose the problem on my own; but as admitted earlier; this was the first time I've rigged cables since airframe and powerplant school two and a half years ago. I thought it was unlikely that I caused the misrouting of the cable because the lower cable would have had to been pulled (when disconnected); inboard past the pulley guard and fed back through on the opposite side (outside) of the guard. When I disconnected the lower cable from the left/H terminating quadrant; the cable was left dangling just underneath the quadrant. There was no need for me to pull the cable inboard past the guard in order to check the bearings in the quadrant.I believe this was a pre-existing error and commend mr. X on his abilities as a mechanic to find and fix the problem. One last reason I believe the cable being on the opposite side of the pulley guard to be pre-existing is that it seemed to be the only error that had a solution to the original write-up.mr. X determined the cable to be misrouted. My lack of personal experience with rigging and routing of cables; along with our quality control department for not seeing the mis-routed cable and my supervisor for administering a task I had no real experience in; and left un-supervised; contributed to the situation.I suggest that proper in-house training or supervision be included; when administering new tasks; or work unfamiliar to a mechanic.

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Original NASA ASRS Text

Title: A Mechanic inexperienced with the aileron cable runs on a DeHavilland DHC-8-100 and an Inspector; did not notice a left-hand aileron cable was previously routed on the outside of an aileron Terminating Quadrant Guard. The aircraft had arrived with a pilot write-up for aileron controls feeling rough.

Narrative: A DHC-8-100 arrived in the morning with a pilot write-up of the aileron controls feeling a bit rough. My Supervisor advised me to check Tensions within the system. I took (cable) readings at the left-hand (L/H) Rear spar and found them to be a bit low. Prior to tightening (cables) to proper Tensions; my Supervisor also advised me to check for roughness in the Terminating Quadrant in the L/H wing.I slackened the cable enough to disconnect the cable from the Quadrant; to spin the Quadrant by hand and check for worn or migrating bearings. The Quadrant checked out fine and the cable was reattached and Tensioned to the proper level. The night shift ended up changing the right-hand (R/H) Aileron Terminating Quadrant and the next morning it departed on an Test Flight.Upon return from the Test Flight; the Controls were still found to be a little rough and further troubleshooting commenced. A fellow Mechanic; Mr. X; found the L/H aileron Rear spar lower cable misrouted. Reference Illustrated Parts Catalog (IPC) 27-12-00. The lower cable was found to be running outside and against the Pulley Guard (item # 440). After routing the cable on the correct side of the Pulley Guard; the ailerons worked properly.Afterwards the question came about as to whether or not I caused the misrouting of the cable during my rigging procedures and I replied that it was unlikely. Granted; I should have been able to diagnose the problem on my own; but as admitted earlier; this was the first time I've rigged cables since Airframe and Powerplant school two and a half years ago. I thought it was unlikely that I caused the misrouting of the cable because the lower cable would have had to been pulled (when disconnected); inboard past the Pulley Guard and fed back through on the opposite side (outside) of the Guard. When I disconnected the lower cable from the L/H Terminating Quadrant; the cable was left dangling just underneath the Quadrant. There was no need for me to pull the cable inboard past the Guard in order to check the bearings in the Quadrant.I believe this was a pre-existing error and commend Mr. X on his abilities as a Mechanic to find and fix the problem. One last reason I believe the cable being on the opposite side of the pulley guard to be pre-existing is that it seemed to be the only error that had a solution to the original Write-up.Mr. X determined the cable to be misrouted. My lack of personal experience with rigging and routing of cables; along with our Quality Control Department for not seeing the mis-routed cable and my Supervisor for administering a Task I had no real experience in; and left un-supervised; contributed to the situation.I suggest that proper in-house Training or Supervision be included; when administering new Tasks; or work unfamiliar to a Mechanic.

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.