AD FAA-2007-27980

The FAA is adopting a new airworthiness directive (AD) for certain Learjet Model 45 airplanes. This AD requires deactivating the auxiliary power unit (APU), capping/plugging the fuel lines to the APU, and removing the APU fuel shutoff valve. This AD results from reports of fuel leaking from the APU fuel shutoff valve into a flammable fluid fire protection area that is also interconnected with the main landing gear's wheel well bay. We are issuing this AD to prevent fuel leaking from the fuel shutoff valve of the APU, which could result in an uncontrollable fire and adversely affect the airplane's continued safe flight and landing.