Date: 201501
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: MD-83
Operator: Air Carrier
Operating under: Part 121
Flight phase: Parked
Aircraft component: Powerplant Fire Extinguishing
Reporter organization: Air Carrier
Reporter function: Technician
Reporter qualification: Maintenance Airframe; Maintenance Powerplant
Human factors: Communication Breakdown; Situational Awareness
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Maintenance
When detected: Other During Maintenance
Result: General Maintenance Action
Contributing factors: Manuals; Incorrect / Not Installed / Unavailable Part; Aircraft; Human Factors
Primary problem: Human Factors

Narrative: I was made aware through my company's compliance department that the installation of extinguisher deployment lines may have been incorrectly routed by me. I am also aware that maintenance on the same extinguisher deployment lines occurred after me and before the lines were said to be discovered incorrectly routed. I removed and replaced the Number-Two fire extinguisher bottle as a result of a low pressure indication in the cockpit. I performed this maintenance task at the standards which I have practiced all of my career. At no time in my career have I ever knowingly performed tasks counter to written procedures. My approach to my work has always been of a serious nature treating each task as if my own family's life depended on it. To the best of my recollection I installed the lines as the figure showed them to be and I was reassured when the very large flex lines aligned for fitting. I am aware however that the improper routing of these lines can have very serious consequences.

Callback: Reporter stated that part of the fire bottle installation includes a specific leak check that pressurizes the large metal braided discharge flex lines that connect to each fire bottle. There are only two fire bottles (total) that supply fire extinguishing for the left and right engines and APU. The large flex lines are disconnected and pressurized air is applied to each line routed from each fire bottle to the left or right engine discharge nozzles in each engine compartment. The exit nozzles are also capped off during the test. The purpose is to verify that no leaks occur in the discharge lines that reduce the available fire extinguishing agent.Reporter stated he could not accomplish the leak test of the discharge lines because his station did not have the proper equipment to perform the test. He believes that either the Maintenance Manual or some other document allowed for the leak test to be deferred for a period of time. The leak check was actually accomplished later at a different Maintenance Station. Not until the MD-83 was brought into one of their Base Maintenance Stations did the crossed-connections of the fire bottle large flex lines become known. Had an engine fire occurred with the cross-connections he's not sure if each engine would have had only one fire bottle available; or if discharge would have gone to the engine not on fire.



Synopsis: An Aircraft Maintenance Technician (AMT) was inform by his Quality Assurance department that he may have incorrectly routed the # 2 Fire Extinguisher bottle discharge lines on an MD-83 aircraft. Technician noted that other maintenance had occurred on the same fire bottle discharge lines he had previously connected prior to their Base Maintenance technicians discovering the cross-connected lines.