Date: 201202
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Light: Dusk
Aircraft: A319
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Parked
Aircraft component: Powerplant Fire Extinguishing
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Inspector; Technician
Reporter qualification: Maintenance Powerplant; Maintenance Airframe
Human factors: Fatigue; Situational Awareness; Troubleshooting; Workload; Communication Breakdown; Confusion; Distraction
Second reporter function: Technician
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Aircraft In Service At Gate
Result: General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Incorrect / Not Installed / Unavailable Part; Weather; Staffing; Procedure; MEL; Logbook Entry; Human Factors; Environment - Non Weather Related; Company Policy; Aircraft
Primary problem: Human Factors

Narrative: An aircraft was on delay for a maintenance discrepancy on another gate; that aircraft was subsequently taken out of service. Another aircraft was used as a replacement for this flight. The replacement aircraft was moved from the east auxiliary pad to the gate on short notice so the flight could dispatch. At departure time; the flight crew notified Maintenance that they had a malfunction with the Engine Fire Detection System. I arrived at the aircraft to assess the situation. I determined after some preliminary troubleshooting that the Number One Fire Bottle Squib indication light for the number two engine was not illuminating during testing. I determined that MEL 26-21-02A would be an effective solution; but it would require additional in-depth troubleshooting of the Fire Detection and Suppression System inside the engine pylon before the MEL could be applied. This would cause considerable delay in departure. I briefed the flight crew of the situation; they were obviously displeased. While troubleshooting the Fire Protection Indication on the Fire Control Panel in the cockpit; the Number One Fire Bottle for the #2 engine was inadvertently discharged. The fire bottle was replaced inside the engine pylon; but in the course of this maintenance procedure; the explosive squib used to activate the fire bottle was not replaced. A new Fire Bottle Squib was not included with the replacement Fire Bottle Assembly. The Troubleshooting Procedures were completed and it was determined that MEL 26.21.02A could be applied in this situation and the aircraft returned to service. Late in my shift with very low outdoor air temperatures and several through flight aircraft in my work area; I was tasked with troubleshooting the Fire Indication/Suppression System for an aircraft at departure time. Suggest adequate staffing to address the daily workload placed on maintenance personnel with adequate and complete parts availability and support. [We need] a work environment without the ongoing disruption and upheaval of multiple interests with differing agendas and divergent goals.


Second narrative: An aircraft was pulled from service earlier in the shift for mechanical issue and swapped with another spare aircraft. We moved the spare aircraft to the gate from the auxiliary (AUX) pad. After some time the same flight crew from the first aircraft called Maintenance with a problem and asked that we come talk with them. The #2 engine; Number-1 Fire Bottle Squib light would not test on pre-flight. Looking for an MEL it was found that it could be MEL'd if you first check the wiring system. During the testing of the squib wiring system; we inadvertently discharged the #1 fire bottle [for #2 engine]. A new fire bottle was ordered and after some time with the pilot standing and watching; the discharged bottle was replaced. The new fire bottle did not come with the plumbing coupling; so it was transferred from the old bottle and the unserviceable squib was mistakenly reinstalled at this point. When the job was completed; the Squib Test Light in the cockpit had the same issue; so the MEL 26-21-02A was applied and the aircraft was returned to service.Late in my shift the temperature dropped down to single digit; to the low teens and being a little fatigued; my alertness was compromised. With my fingers freezing with pain and the crew wanting the aircraft; the unserviceable squib was mistakenly installed.I feel that even though it would cause short term delays; frequent breaks need to be taken when the weather becomes intolerable and you feel fatigue setting in. This would give you a chance to warm up a bit and gather your thought process in order to perform the job at hand correctly. Although flight crews should not be ignored; they need to be made aware that when maintenance is being performed; to insure the safety of the aircraft/crew and passengers or any area of the aircraft that the distraction of them standing over you tapping their feet does not help. Insufficient manpower leads to high workload and task saturation. Perhaps a few more people could be hired to help spread out the workload.


Synopsis: Three Line Mechanics describe a chain of events that led to an inadvertent discharge of an A319 aircraft's forward (#1) Fire Bottle for #2 Engine. Mechanics were attempting to accomplish a Fire Bottle/Squib Firing Circuit Test Maintenance (M) procedure; required by their MEL; to defer a Squib Indication fault. Excessive cold and fatigue were also noted.