Maintenance Powerplant; Maintenance Airframe
Situational Awareness; Time Pressure; Workload; Distraction
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Aircraft; Human Factors
Aircraft X; an ERJ-170; had a failed Generator Input/Output Module-2 card (GEN I/O 2) and needed to leave soon for a flight to a larger Maintenance Base for scheduled maintenance that night. We didn't have a card here to replace it with; but had Aircraft-Y (ACFT-Y) with the same type of card. So I took ACFT-Y's GEN I/O 2 card out; noting the arrow was facing UP. Took it to Aircraft-X (ACFT-X) to replace it (with the arrow facing Up; the way I removed it) with the canned (cannibalized) [card] from ACFT-Y. Loaded the card [into Aircraft-X] and ran the Ops Check; everything tested good at the time. We went AOG for a new card for ACFT-Y.  Once we received it; I installed the new card in ACFT-Y with the arrow; face Up; the way I removed it. Loaded the card and ran the Ops Check and everything passed. We had the Aircraft Maintenance Manual (AMM) with us to locate the card slot number in the Modular Avionics Unit (MAU2); but in the rush of getting the card out [of Aircraft-Y] and loaded into our Maintenance Tracking and Parts computer program to be [considered] Serviceable to be installed on ACFT-X; we did not notice the step annotating the arrow [on the card] should be in the DOWN position. With both Aircraft passing the Operational Checks we went about thinking it was correct until there was an error a few days later that it was then brought to my attention it was installed upside down on both aircraft.[Contributor] Wanting to make sure the aircraft was fixed before the flight crew timed out; to get it to a Base for its scheduled workload; the task was done without full notice to the AMM stating the direction of the arrows. [Recommend] Be sure to fully read all steps of the AMM. Do not believe [assume] that the current installation of a part is the correct configuration for it to be in. Cannibalize part for another aircraft. Ramp. Gate.
A Line Aircraft Maintenance Technician (AMT) was informed he had installed a cannibalized Generator Input/Output module-2 card (GEN I/O-2) upside down into the Modular Avionics Unit-2 (MAU2) on an outbound ERJ-170 aircraft. Technician noted that even though both cards were removed and reinstalled with the arrows facing up; instead of down; they still passed the AMM Operational Checks.