Learjet: Common Exchanged Aircraft Parts

October 2013

Duncan Aviation has built and maintained one of the largest business aircraft parts inventory in the industry. Our team of aviation professionals has the experience, contacts and connections to identify and secure some of the hardest to find business aircraft parts.

Because of our long history and experience with the Learjet aircraft, we know the most commonly exchanged parts and keep an inventory available to meet customer needs.

Below are some of the more commonly exchanged life-limited parts on a Learjet airframe that have been known to not make the next Time Before Overhaul (TBO).

Stab Actuator 2332540-214 The stab actuator adjusts the horizontal stabilizer to provide longitudinal trim. The actuator comes due for overhaul every 600 hours. Failures that sometimes occur are unit trips autopilot off line, & no manual trim.

	Modulating Valve 6600202-1, -3 The modulating valve regulates the mixing of bleed air to control temperature. If it becomes stuck open or closed, aircraft cabin temperatures can become uncomfortable. The value is spring-loaded and sometimes fails to compress on run-up. It is not uncommon for these valves to leak over time.
	Hydraulic Pump 6600301-3 The hydraulic pump controls the flow of hydraulic fluid through the system. Hydraulic fluid leaking at the drive shaft is a symptom of the nose seal failing to make a proper seal.
	Static Inverter 6608109-3 The static inverter powers all onboard instruments that need aircraft power. Failures include unit being intermittent, pops breaker, and low or no output.
	NWS Servo 6608278-2 The nose wheel steering servo controls the rate of turn while aircraft is being taxied. Common failures are time change, pops breaker, low torque and pulls to the right or left.