Learjet Winter 2000

SB 35/36-24-20 Replace Your Splices
Is Your Autopilot Developing A Mind Of Its Own?
Take Off Warning For 31s, 55Cs & 60s
Installing Hard Erosion Boots
Learjet Market Info Provided By JetResources / Call 800.228.4277 Ask For JetResources

Download PDF Version

SB 35/36-24-20 Replace Your Splices

SB 35/36-24-20 is a recommended bulletin that involves replacement SB 35/36-24-20 Replace Your Splices of nylon insulated wire splices with higher temperature resistant PVF2 insulated splices. The bulletin applies to later 35 and 36 series aircraft (refer to the SB for effectivity). As we have accomplished this bulletin, we have found the affected splices to be discolored and brittle. All were definitely in need of replacement. Operators should also be aware that the access time, as refered to in the bulletin, can be considerably more than stated.

For more information, please contact Bill Schroeder in LNK at 800.228.4277 or contact Pete Kilmartin in BTL at 800.525.2376.

Is Your Autopilot Developing A Mind Of Its Own?

Just as we need our sense of sight to fly an aircraft, an autopilot needs to know what attitude the aircraft is at and the rate of change in attitude to compute a proper response. The vertical gyro acts as the “eyes” of the autopilot. If this information is missing, the autopilot will give a “hard-over” response in whatever direction drive is required. If the gyro is sluggish or slow, the rate information will not be correct for the autopilot and the result will be wing-rock or pitch porpoise. This symptom is usually fairly slow and constant. The attitude information is electrically picked off slip rings in the gyro by brushes. If the contact between brush and slip ring becomes intermittent due to tension or resistive contact, the autopilot interprets this as change in attitude and attempts to respond accordingly, resulting in jittery or rapid oscillation. Depending on the gyro installed there may also be Service Bulletins addressing this problem.

For more info, contact Larry Troyer in LNK at 800.228.4277 or contact Pete Kilmartin in BTL at 800.525.2376.

Take Off Warning For 31s, 55Cs & 60s

Duncan technicians have seen several cases of the warning horn going off when everything is in take off configuration. In every case we have found that the park brake warning light bulb was burned out.

So make sure the parking brake light bulb is good before jumping head long into troubleshooting.

Also, don’t look for a warning box in the 55Cs and 60s because you won’t find one; Learjet put the circuitry in the autopilot electric box.

For info, contact Bill Schroeder in LNK at 800.228.4277.

Installing Hard Erosion Boots

When installing hard erosion boots on Learjet radomes and tip tanks, make sure there is a one-inch gap in the adhesive at the bottom of the boot. This allows drainage of moisture, reducing the chance for corrosion or freezing causing damage to tip tank or radome. Also apply a 1/4 bead of sealer around the anti-ice hole on the radome to stop alcohol and water from entering the voided area under the boot.

Learjet Market Info Provided By JetResources / Call 800.228.4277 Ask For JetResources

A/C Model	For Sale/% of Fleet	Change from Last Six Months	Asking Price Range	Comments
35/A	63/10%	+31%	<$2 to mid $4s	Pricing 6-8% off peak
31/A	16/8%	+100%	low $3s to mid $5s	Sales have slowed to a halt
55	18/15%	+38%	mid $4s to mid $5s	Good selection of aircraft
60	413%	-33%	low $8s to low $9s	1-2 selling per month