Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain Raytheon Model DH.125, HS.125, and BH.125 series airplanes; BAe.125 series 800A (C-29A and U-125) and 800B airplanes; and Hawker 800 (including variant U-125A) and 800XP airplanes. This proposed AD would require installing insulating blankets on the engine compartment firewall and the wire harness passing through the firewall fairlead. This proposed AD is prompted by a report indicating that insulation on the wire harness passing through the firewall fairlead ignited on the fuselage side of the firewall. We are proposing this AD to prevent a fire in the engine compartment from causing possible ignition of outgassing wire insulation on the fuselage side of the firewall, which could lead to an uncontrollable fire in the fuselage.