Learjet Summer 2005

• 60 Model 3-Rotor Brake Actuators
• 45 Model SB 45-32-12
• Enhanced Surveillance Mandate
• Lear 60 - IBR Inspection

60 Model 3-Rotor Brake Actuators

— Dave Schiver

Now that SB 60-32-12 is released and being installed in the field, take note that there is a change in Chapter 5 in regards to the lubrication schedule of the down-lock switch ball. When installing the new style actuators for the 3-rotor brake, the part number changes from 6027100-XXX to 6600264-XXX. The requirement to lubricate the down-lock switch ball is removed with the new actuator. The old style actuator remains at the C5 inspection but the IRN changes from a H1221015 to a M1221040 due to the part number call-out. Please note that when removing and re-installing the down-lock switch ball on the new actuator that the lubricant also changes from LPS3 to NYOSIL M25.

45 Model SB 45-32-12

— Dave Schiver

On SB 45-32-12, which installs a break plug for the WOW switch on the nose strut, there are issues to be aware of.

The first appears on page four of the SB. In step (8) (a) 2), two holes are to be drilled for attaching the bracket for J1/P1 into the aircraft structure. If measurements are not very precise, there is a chance of drilling into the ”waffle” structure of the forward pressure bulkhead. This area is aft of the #1 AHRS and is very difficult to see.

Another issue is found in the next step, page four, (8) (b) 1). Here two existing fasteners are to be drilled for installation of another bracket to support the 90° strain relief for J1/P1. There is a wire bundle routed behind that area in a “U” channel. This is also hidden by the #1 AHRS and is located inboard of the AHRS.

Remember that the aircraft structure is more important than the location of brackets to install clamps. When drilling, always be aware of what may be on the other side.

Enhanced Surveillance Mandate

— Dave Pleskac

Enhanced Surveillance (EHS) is now mandatory for all IFR flights within the airspace of Germany and Great Britain, and will be mandatory in France March 31, 2006. However, EUROCONTROL has established a transition period until March 31, 2007. Operators who do not currently have Enhanced Mode S Surveillance must apply for an exemption. For more information about this installation, please contact Dave Pleskac at 800.228.4277.

Lear 60 - IBR Inspection

— Bill Walker

Duncan Aviation has worked closely with Learjet and Pratt & Whitney to acquire all necessary tooling for this inspection and Pratt & Whitney- Canada has trained Duncan Aviation technicians from both our Lincoln and Battle Creek facilities for the IBR Inspection.

For engines that are pre-SB 24425, initial inspections must be by 2500 hours TT (total time). and for engines post-SB 24425, the inspection must be done by 1200 hours TT. Be sure to read chapter 05-20-00, Table 1 of the maintenance manual to determine your exact requirement and in either case, track the hours the engines have accumulated since January 30, 2004. This inspection requires the removal of the aircraft inlet as well as the engine spinner and the LP compressor. NDT will perform an eddy current inspection of the 1st stage HP compressor rotor. This is a repetitive 300 hour inspection with an allowance of 25 hours to schedule the inspection. There is a program that pays for this inspection, however, it does not pay for travel expenses to bring technicians to the aircraft, for inspection performed outside of an authorized facility nor does it pay for a functional check.

To discuss this topic further please contact Bill Walker or Jon Dodson at 800.228.4277.

( Return to top )