The NTSB issued a rare urgent safety recommendation on Tuesday, warning pilots that Piper PA-31T-series aircraft may have unsafe wiring that could lead to arcing and cause fires. The urgent safety recommendation is based upon preliminary findings in the ongoing investigation of the July 29, 2016, inflight breakup of a Piper PA-31T medical transport flight in California. Investigators found evidence of thermal damage near the airplane's main electrical bus circuit breaker panel. This enclosed space also includes hydraulic lines that run directly below the panel. Further examination of the wiring in this area showed evidence of electrical arcing, and sections of the adjacent hydraulic lines were consumed by inflight fire. Evidence thus far indicates that the inflight fire occurred in the area where these electrical wires and adjacent hydraulic lines may have been in contact, the NTSB said. NTSB urgent safety recommendations are issued in advance of the completion of an investigation when the Board believes an imminent threat to life and safety exists, based upon findings of the ongoing investigation.
This is a companion discussion topic for the original entry at https://www.avweb.com/news/ntsb-warns-of-possible-fires-from-piper-pa-31t-wiring