Communication Breakdown; Distraction; Troubleshooting; Situational Awareness
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural FAR
General Maintenance Action
Aircraft; Chart Or Publication; Human Factors; Procedure; Manuals; Logbook Entry
I received an ACARS transmission stating that Aircraft X; a B717; was experiencing an Altitude problem with its Integrated Standby Instrument System (ISIS). I searched the Fault Isolation Manual (FIM) for a procedure which mirrored the discrepancy described in the transmission. In my search I found FIM 34-11; Task 801; Attitude Problems-Fault Isolation which I inadvertently read as Altitude Problem. After reviewing the FIM Task; I did not feel the procedure included sufficient steps to perform a complete check of the system. Given that; I took an additional step and consulted the Aircraft Maintenance Manual (AMM) looking for a procedure that would perform a more thorough Check. I used Aircraft Maintenance Manual (AMM) reference XX-XX-XX; sub-task XX-XX-XX-XXX-XXX; Operational Test of the ISIS because it provided a more comprehensive system test than FIM 34-11; Task 801. I contacted the Mechanic on site and discussed the problem Aircraft X was experiencing. I faxed him the paperwork which included the FIM reference along with the AMM reference. In an effort to avoid confusion on page two of the AMM; I marked through the Functional Test procedures with an 'X' indicating that these steps will not be performed. When the Mechanic received the paperwork; he called and we discussed the current status and the [Flight] crew comments that the system was now functioning normally. I gave verbal instruction to the Mechanic on how to test the system even though it was reportedly not in working order. The Mechanic performed the test and reported that the system checked out and was operational; at which time we signed-off the discrepancy together. One week later; it was brought to my attention that some questions had been raised surrounding the incident; I was confident that the system was properly checked and felt the inquiry would be dismissed without merit. It was not until I looked more closely at the title of the [Test] procedure that I realized; to my dismay; it read Attitude and not Altitude.
A Maintenance Controller reports he inadvertently misread a Fault Isolation Manual (FIM) Chapter 34-11 AttitudeFault Isolation Problem as reading Altitude Problems; while researching a Test procedure he later used to sign-off a B717 aircraft with an Altitude discrepancy in the Integrated Standby Instrument System (ISIS).