Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Raytheon Model DH.125- 400A; BH.125-400A and -600A; HS.125-600A and -700A; BAe 125-800A; and Hawker 800, and Hawker 800 XP series airplanes including military variants (C29A, U125, U125A). This proposal would require a one-time inspection to determine if certain high pressure oxygen hose assemblies are installed, and, if installed, replacement of those hose assemblies with new, improved hose assemblies. This proposal is prompted by a report that certain high pressure oxygen hose assemblies are susceptible to leakage due to those hose assemblies not meeting design specifications during manufacturing. The actions specified by the proposed AD are intended to prevent leaks in high pressure oxygen hose assemblies, which, if not detected and corrected, could result in insufficient oxygen available to the passengers or crew if the cabin pressure altitude should rise to a level requiring emergency oxygen.