A Line Mechanic was informed [that] a CRJ-200 was out of service due to a right engine fire bottle light would not illuminate during a cockpit preflight test. Mechanic had replaced the same fire bottle two weeks earlier; but the cockpit 'press to test' procedure was not part of the maintenance manual fire bottle installation procedures.
Synopsis
A Line Mechanic was informed [that] a CRJ-200 was out of service due to a right engine fire bottle light would not illuminate during a cockpit preflight test. Mechanic had replaced the same fire bottle two weeks earlier; but the cockpit 'press to test' procedure was not part of the maintenance manual fire bottle installation procedures.
Narrative
I was notified that aircraft X; a CRJ-200; was broke all day for a right engine fire bottle light [that] would not illuminate. I was informed that a [Line] Mechanic stated he found a cap that was not removed [from fire bottle]. This was the only engine fire bottle that I have ever replaced. Because of that; I printed the Aircraft Maintenance Manual (AMM) task 26-21-07 (removal/install) to make sure I had the correct fire bottle.I followed each step and removed the caps and placed them on the returned [removed] fire bottle. I installed three cannon plugs and two discharge lines and four bolts as required. I then printed AMM task 26-21-07. I followed the task and all tested good. I received both squib messages on both tests. The was no 'ENG BTL LO' message either. The procedure that this pilot performed is; [to] my understanding; done before each flight; as well as every #2 line check.I am not sure if anything could be done differently since I know I followed procedures. I would suggest adding the procedure that the flight crews perform to the AMM task. I am surprised that after reading it again that it isn't part of that task.
NASA callback
Reporter stated the problem with the right engine fire bottle cockpit light not illuminating did not show up on the CRJ-200 aircraft until two weeks after he replaced the same fire bottle. The two tests he did involved testing the squibs. But the cockpit preflight tests [that] flight crew perform are a 'press to test' for the engine fire warning and fire bottle continuity test.Reporter stated no one has been able to tell him which cap on the fire bottle was not removed from the bottle he installed that was suppose to be the cause of the failed fire bottle 'press to test'; especially since the problem did not show up for two weeks. Reporter stated since that incident; his air carrier has added the 'press to test' cockpit test to the Maintenance Manual fire bottle installation procedure.
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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.