EMB ERJ 190/195 ER/LR
Maintenance Airframe; Maintenance Powerplant
Communication Breakdown; Confusion; Workload; Time Pressure; Situational Awareness; Distraction
Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Became Reoriented; General Maintenance Action
Aircraft; Human Factors
I was assigned to taxi an ERJ-170 aircraft from the gate to the hangar for maintenance.  Number 2 engine had a Boroscope scheduled and I elected to perform a single engine taxi to allow the #2 engine to cool down for Inspection. I dry-motored the #2 engine once after pushback to cool the Interstage Turbine Temperature (ITT) closer to Boroscope allowable temperatures. [Performed] normal start on the opposite engine; and received taxi clearance. I began to dry-motor the #2 engine once again during taxi; at which point we received an amended taxi clearance. As my right seater read back the clearance; he was 'stepped-on' by another radio transmission and the Controller didn't hear him read back the hold short portion of the clearance. The Controller then asked 'Air Carrier X read back hold short'; and my right seater wasn't aware that his transmission was 'stepped on'; so I stepped in and read back the hold short portion of our amended clearance. At that time I looked back down at my chronograph (watch); which I had started to monitor my starter duty limits; and had exceeded the 30-second limit by 5-seconds. I quickly reached down to stop motoring the #2 engine; and accidentally turned the #1 Engine Start/Stop switch 'off' instead of #2. I brought the aircraft to a stop at the instructed hold short position; allowed the engine to spool down; and then restarted the #1 engine. A few minutes later; we received additional taxi clearance to the hangar; and proceeded with no problems.  I felt pressure from lack of time to accomplish maintenance. This was the last plane in; and the first plane out; and I foolishly decided to multi-task the dry-motor operation while the aircraft was under movement; to save time later.
A Line Mechanic describes his efforts to multi-task a #2 engine dry-motor operation while taxiing their ERJ-170 aircraft and communicating with Ground Control. He felt pressure from lack of time to accomplish all the scheduled maintenance work.