Summary
We propose to adopt a new airworthiness directive (AD) for all EADS CASA (Type Certificate Previously Held by Construcciones Aeron[aacute]uticas, S.A.) Model CN-235, CN-235-100, CN-235-200, and CN-235-300 airplanes. This proposed AD was prompted by reports of incorrect electrical polarity connections on engine fire extinguishing discharge cartridges. This proposed AD would require a one-time inspection to identify the correct polarity for each pair of electrical connectors on each engine fire extinguisher cartridge, and repair if necessary. We are proposing this AD to detect and correct incorrect polarity connections, which could prevent the actuation of the discharge cartridge in case of automatic fire detection or manual initiation during a potential engine fire, and could result in damage to the airplane and injury to passengers.