Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to all Short Brothers Model SD3-60 SHERPA and SD3 SHERPA series airplanes. This proposal would require removing the aluminum alloy oxygen pipe assembly and replacing it with a stainless steel assembly. This proposal is prompted by the issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by the proposed AD are intended to prevent aluminum oxygen tubing from bursting and releasing a high-pressure oxygen flow into the passenger cabin, which could result in a fire hazard during flight.