Narrative:

Mechanic 'X' and I got called to the gate because a crj-900 was returning with a mechanical issue. Crew told us 'left TR unsafe' (left thrust reverser) message came on. Since the passengers were waiting; we proceeded immediately to stow and defer left-hand TR. While installing the lock-out kit we could not start one of the four bolts on the outboard (ob) lock plate (damaged bolt).remembering being done before (that an aircraft was released with only three bolts on one of the lock plate's); we decided to install the other three bolts; safety them and release the airplane with a deferred TR per MEL 78-30-1 (C). We did not realize that in order to do this we should get an engineering order (eo) for each airplane; (there is no generic eo to release all crj-900's with only three bolts installed); and put item on short watch list.when we got back to the hanger; I immediately called ZZZ1 mechanics to tell them (aircraft was flying to ZZZ1) and address the issue. ZZZ1 mechanics found and installed missing bolt.we did this because people were waiting in the airplane; it was really cold and windy in ZZZ; and since I knew it was done before; try to do the same; yet forgot to do proper paper work.I suggest reminding people that one eo for one crj-900 cannot be used on other same type of aircraft.

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Original NASA ASRS Text

Title: A Line Mechanic reports about a CRJ-900 that returned to gate with a (left Thrust Reverser) 'L TR unsafe' message. The Left engine Reverser was deferred; but Mechanics failed to get an Engineering Order to allow for Maintenance Release; with only three of the four Reverser Lock-out bolts installed on the outboard Lock plate.

Narrative: Mechanic 'X' and I got called to the gate because a CRJ-900 was returning with a mechanical issue. Crew told us 'L TR unsafe' (left Thrust Reverser) message came on. Since the passengers were waiting; we proceeded immediately to stow and defer Left-hand TR. While installing the Lock-Out kit we could not start one of the four bolts on the outboard (OB) Lock plate (damaged bolt).Remembering being done before (that an aircraft was released with only three bolts on one of the Lock plate's); we decided to install the other three bolts; safety them and Release the airplane with a deferred TR per MEL 78-30-1 (C). We did not realize that in order to do this we should get an Engineering Order (EO) for each airplane; (there is no generic EO to Release all CRJ-900's with only three bolts installed); and put item on short watch list.When we got back to the Hanger; I immediately called ZZZ1 Mechanics to tell them (aircraft was flying to ZZZ1) and address the issue. ZZZ1 Mechanics found and installed missing bolt.We did this because people were waiting in the airplane; it was really cold and windy in ZZZ; and since I knew it was done before; try to do the same; yet forgot to do proper paper work.I suggest reminding people that one EO for one CRJ-900 cannot be used on other same type of aircraft.

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.