AD FAA-2015-3139

We are adopting a new airworthiness directive (AD) for all BAE Systems (Operations) Limited Model ATP airplanes. This AD requires a one-time inspection for solder deposited on the frangible plug of certain engine and auxiliary power unit (APU) fire extinguishers. This AD was prompted by reports of a fire extinguisher that failed to discharge due to solder deposited on the frangible plug of the fire extinguisher. We are issuing this AD to detect and correct solder deposited on the frangible plug of the fire extinguisher, which could result in failure of the fire extinguisher to discharge, and consequent inability to put out a fire in an engine or in the APU.