Maintenance technician reported that when electrical power was reapplied following the routine repla...

Narrative:

Maintenance personnel were instructed to [remove and replace] the #1 engine fire bottle that was due for scheduled maintenance. [The] acting lead mechanic called and stated that during the fire bottle change on the aircraft; power was applied and the fire bottle was discharged. Upon investigation it was found that the power and the ground wires on the fire bottle squib had been swapped and the squib was not wired properly. During investigation the mechanic performing the work stated that the wires were pre labeled but the following day when another fire bottle was installed no labels were noted on the wires and a full run down of the wiring print had to take place prior to installing the replacement bottle. Mechanic was counseled on the need to label everything removed no matter how small it may be.

Original NASA ASRS Text

Title: Maintenance Technician reported that when electrical power was reapplied following the routine replacement of a Metroliner engine fire extinguisher bottle; the bottle was unexpectedly discharged. He revealed that wires had been incorrectly connected due to mislabeling of the wires.

Narrative: Maintenance personnel were instructed to [remove and replace] the #1 engine fire bottle that was due for scheduled maintenance. [The] acting lead mechanic called and stated that during the fire bottle change on the aircraft; power was applied and the fire bottle was discharged. Upon investigation it was found that the power and the ground wires on the fire bottle squib had been swapped and the squib was not wired properly. During investigation the mechanic performing the work stated that the wires were pre labeled but the following day when another fire bottle was installed no labels were noted on the wires and a full run down of the wiring print had to take place prior to installing the replacement bottle. Mechanic was counseled on the need to label everything removed no matter how small it may be.

Data retrieved from NASA's ASRS site 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.

Attributes
ACN	1293413
Time
Date	201508
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Light	Daylight
Aircraft 1
Make Model Name	SA-227 AC Metro III
Operating Under FAR Part	Part 121
Flight Phase	Parked
Component
Aircraft Component	Powerplant Fire Extinguishing
Person 1
Function	Other / Unknown
Qualification	Maintenance Airframe Maintenance Powerplant
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy

Maintenance technician reported that when electrical power was reapplied following the routine replacement of a metroliner engine fire extinguisher bottle; the bottle was unexpectedly discharged. He revealed that wires had been incorrectly connected due to mislabeling of the wires.