Narrative:

Before the aircraft arrived; maintenance control advised us that aircraft X will arrive with pressurization issues. I was the lead [mechanic] in charge during the overnight shift. I assigned two technicians to remove the controller from aircraft Y; also an A320; which was aircraft out of service (aos) in ZZZ in preparation for the arrival of aircraft X. The aircraft maintenance manual (amm) reference [chapter] (21-31-34) for the cabin pressure controller (cpc) was printed from airnav [airbus manual]. The cpc and pack temperature (temp) controller (ptc) were located next to each other in the forward electronic compartment. The placard identifier next to each controller had the number two [#2] written and it was taken for granted that the part was the correct part that was removed without realizing that it was the incorrect part. I told the technician to remove the cpc and the ptc was removed instead; without realizing. The technicians may have misunderstood exactly what part was to be removed. I went to the flight deck and debriefed the flight crew and told the technicians that I will pull the circuit breakers (C/B) and let them know when it would be safe to replace the controller on aircraft X. They installed the part and I proceeded to perform the operational (ops) check per the amm. The ops check passed and no ctc faults were present. Since the controller had an intermittent fault; it was not currently faulting. I also ran both engines per maintenance control's request to verify that no faults returned after [electrical] power swap. All checked ok. I verified the effectivity of the cpc before aircraft X arrived and it was effective to both aircraft X and Y. However; the incorrect part was removed from aircraft Y; that was located next to the cpc and that part was not effective for aircraft X. I was made aware of the configuration issue after aircraft departed.

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Original NASA ASRS Text

Title: A Line Lead Mechanic explains how a Pack Temperature Controller (PTC) was removed and replaced (R/R) instead of a Cabin Pressure Controller (CPC) for cabin faults appearing after engine starts on an A320 aircraft. Aircraft later diverted after incorrect part replaced.

Narrative: Before the aircraft arrived; Maintenance Control advised us that Aircraft X will arrive with pressurization issues. I was the Lead [Mechanic] in charge during the overnight shift. I assigned two technicians to remove the controller from Aircraft Y; also an A320; which was Aircraft Out of Service (AOS) in ZZZ in preparation for the arrival of Aircraft X. The Aircraft Maintenance Manual (AMM) reference [Chapter] (21-31-34) for the Cabin Pressure Controller (CPC) was printed from Airnav [Airbus Manual]. The CPC and Pack Temperature (Temp) Controller (PTC) were located next to each other in the Forward Electronic Compartment. The placard identifier next to each controller had the Number Two [#2] written and it was taken for granted that the part was the correct part that was removed without realizing that it was the incorrect part. I told the Technician to remove the CPC and the PTC was removed instead; without realizing. The Technicians may have misunderstood exactly what part was to be removed. I went to the flight deck and debriefed the flight crew and told the technicians that I will pull the Circuit Breakers (C/B) and let them know when it would be safe to replace the controller on Aircraft X. They installed the part and I proceeded to perform the Operational (Ops) Check per the AMM. The Ops Check passed and no CTC faults were present. Since the controller had an intermittent fault; it was not currently faulting. I also ran both engines per Maintenance Control's request to verify that no faults returned after [electrical] power swap. All checked OK. I verified the effectivity of the CPC before Aircraft X arrived and it was effective to both Aircraft X and Y. However; the incorrect part was removed from Aircraft Y; that was located next to the CPC and that part was not effective for Aircraft X. I was made aware of the configuration issue after aircraft departed.

Data retrieved from NASA's ASRS site as of July 2013 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.