Narrative:

I fell victim to the dirty dozen; complacency. I was reading the amm (aircraft maintenance manual) to perform the leak test of the P1 and pitot S1 system when; in the middle of the test; I realized the airspeed indicator was not indicating correctly. I went back through the manual to realize that I had read it incorrectly. I saw that the circuit breakers needed to be 'opened' instead of 'closed;' which conflicted with what I thought I read. When I inspected the left and right pitot probes I saw the inner sleeve of our test equipment had melted around it and entered the probes; which caused the erroneous readings. After removing the damaged sleeves I realized that the test equipment; DPS1000; had a maximum limit of 60 HZ and should not have been plugged in to the aircraft galley outlet;which exceeds that limit. I did not see the limit on the test device due to it being on when I plugged it in. It booted up and tested normally so I did not look at that part of the device. I detected the problem by realizing the airspeed indication was not lining up correctly with the test equipment.it was my first time doing any work on pitot probes so I wanted to move slowly and read the manual; after being on the task for 6 hours and at the final stretch to finish it I began to lose focus. After I found the problem I began talking to my partner about writing a report and doing damage control by removing the damaged equipment.when I was looking through the manual my eyes went right to the breakers; glossing over the warnings and cautions. Maybe having those color coded; since we no longer have to print out papers due to the electronic systems in place; would be beneficial and more eye catching.

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Original NASA ASRS Text

Title: CRJ900 Maintenance Technician reported incorrectly performing maintenance procedure.

Narrative: I fell victim to the dirty dozen; complacency. I was reading the AMM (Aircraft Maintenance Manual) to perform the leak test of the P1 and pitot S1 system when; in the middle of the test; I realized the airspeed indicator was not indicating correctly. I went back through the manual to realize that I had read it incorrectly. I saw that the circuit breakers needed to be 'opened' instead of 'closed;' which conflicted with what I thought I read. When I inspected the left and right pitot probes I saw the inner sleeve of our test equipment had melted around it and entered the probes; which caused the erroneous readings. After removing the damaged sleeves I realized that the test equipment; DPS1000; had a maximum limit of 60 HZ and should not have been plugged in to the aircraft galley outlet;which exceeds that limit. I did not see the limit on the test device due to it being on when I plugged it in. It booted up and tested normally so I did not look at that part of the device. I detected the problem by realizing the airspeed indication was not lining up correctly with the test equipment.It was my first time doing any work on pitot probes so I wanted to move slowly and read the manual; after being on the task for 6 hours and at the final stretch to finish it I began to lose focus. After I found the problem I began talking to my partner about writing a report and doing damage control by removing the damaged equipment.When I was looking through the manual my eyes went right to the breakers; glossing over the warnings and cautions. Maybe having those color coded; since we no longer have to print out papers due to the electronic systems in place; would be beneficial and more eye catching.

Data retrieved from NASA's ASRS site 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.