Narrative:

A B767-300 inbound crew wrote up the following irregularity: left eng eec C1; left eng air/oil valve; dispatch was approved for MEL 75-21-02A. The left pimu was interrogated and verified the fault as follows: eec \ch-a and ch-B aoc TR-ck fail and aoc FD-bk fail - flight leg 1.the dispatch manual states to verify that the valve is open and if so; remove and stow the electrical connector from the air/oil heat exchanger. Amt verified that valve was indeed open; but removed the electrical connector from the idg air/oil heat exchanger by mistake. The respective valves are located opposite of each other on the engine; (idg valve is on the right side and engine a/O valve is on the left). Both coolers and valves are of the same type and style.previous experience not withstanding and an incorrect judgment (human error) by the amt; along with a miscommunication from maintenance control over the phone; resulted in the error. Problem was discovered by the flight crew; after taxi out and departure. Maintenance control was notified by maintenance; with additional corrective action to be addressed at the flights destination. Aircraft did not return to gate; or off land at another airport enroute. Flight proceeded normally and on schedule.

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Original NASA ASRS Text

Title: A Mechanic reports about verifying a left engine air/oil heat exchanger valve was open; as a requirement for an MEL 75-21 deferral on a B767-300; but mistakenly disconnected the electrical connector for the PW-4000 IDG air/ oil heat exchanger valve instead.

Narrative: A B767-300 inbound crew wrote up the following irregularity: L Eng EEC C1; L Eng Air/Oil Valve; dispatch was approved for MEL 75-21-02A. The Left PIMU was interrogated and verified the fault as follows: EEC \Ch-A and Ch-B AOC TR-CK Fail and AOC FD-BK Fail - Flight Leg 1.The dispatch manual states to verify that the valve is open and if so; remove and stow the electrical connector from the Air/Oil Heat Exchanger. AMT verified that valve was indeed open; but removed the electrical connector from the IDG Air/Oil Heat Exchanger by mistake. The respective valves are located opposite of each other on the engine; (IDG valve is on the right side and engine A/O valve is on the left). Both coolers and valves are of the same type and style.Previous experience not withstanding and an incorrect judgment (human error) by the AMT; along with a miscommunication from Maintenance Control over the phone; resulted in the error. Problem was discovered by the flight crew; after taxi out and departure. Maintenance Control was notified by Maintenance; with additional corrective action to be addressed at the flights destination. Aircraft did not return to gate; or off land at another airport enroute. Flight proceeded normally and on schedule.

Data retrieved from NASA's ASRS site as of April 2012 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.