Learjet Winter 2005

• 35 Model RVSM Stall Computer Settings
• RVSM and Continued Airworthiness
• Shear Web AD 2004-03-08
• Battery Technology

35 Model RVSM Stall Computer Settings

— Dave Schiver

Ongoing confusion exists on the Stall Warning Computer settings after the Bombardier RVSM STC (ST00321WI-D) has been accomplished. As part of the STC, Rosemount pitot static probes are installed, if not previously complied with. This is usually on the FC-200 autopilot aircraft. The FC- 530 autopilot aircraft have Rosemount probes as part of the system configuration. The supplemental maintenance manual (M100165ICT-SMM-3) calls out the stall computer settings for the FC-200 aircraft to be the same as the FC-530 aircraft. A simple way to remember is to look for Rosemount probes, then the autopilot control head. If it is a FC-530 autopilot, use the Learjet maintenance manual. If there is a FC-200 autopilot, use the STC’s supplemental maintenance manual.

RVSM and Continued Airworthiness

— Dave Lewis

As DRVSM takes affect, continued maintenance will be an ongoing concern. The age and the method by which the aircraft was made RVSM capable will determine how maintenance will be performed. New aircraft are delivered RVSM capable, middle aged aircraft will typically have a factory solution through a factory service bulletin or STC, and older aircraft find their solution through an independent STC.

Some models have more than one solution and this is where the confusion lies. When an aircraft is in for maintenance, the service center must know the exact RVSM solution used.Without this information, wrong procedures could be applied, resulting in an unsafe aircraft or lost schedule.

Duncan Aviation and the local FAA FSDOs strongly encourage operators to carry the RVSM Operations Manual on the aircraft at all times. This includes all the information the facility needs to maintain RVSM to proper standards. The manual will direct technicians to factory maintenance manuals or identify an STC which will have its own instructions for continued airworthiness (ICA). A copy of the STC is typically kept in the RVSM Ops Manual.

Shear Web AD 2004-03-08

— Brad Lennemann

Learjet 31 & 35 model aircraft that have not accomplished Shear Web inspections by March 15, 2005, will be grounded. Repairs/reinspection will be necessary under three different criteria, based upon initial inspection results:

1. Repeat the inspection at intervals not to exceed 1,200 flight hours,
2. Repair and modify shear web within the next 1,200 flight hours, or
3. Repair and modify the shear web before further flight.

March 15th is quickly approaching. If you are not yet in compliance, contact Brad Lennemann for schedule availability at 800.228.4277 ext. 4279.

Battery Technology

— Karl Detweiler

Securaplane and Enersys have developed a true, solid lead acid main aircraft battery. Batteries have been installed on Learjet aircraft and many other corporate aircraft models.

This battery has many advantages. It can be stored fully charged for 24 months with no required maintenance.When in use, it only requires servicing every 18 months. Since it is a true, solid battery, it is rated non-hazardous and can be shipped by standard means.

A 30 month warranty (not pro-rated) begins at the time of installation, and is in addition to the 24 month shelf life. This battery should have the same life span as that of a NiCad battery.

Manufacturers rate their batteries at full capacity when new.When Securaplane says its battery is a 25 amp/hour battery, it is rated 25 amp/hour at 80% of battery capacity, so a new Securaplane 25 amp/hour battery will have a 31 amp/hour performance.

The cost is approximately 1/2 that of a NiCad battery and there is no need to replace it. If cells are needed, the battery can be “reblocked” for about 2/3 the cost of a new battery and has a 30 month warranty. For further information please contact Chris Gress at 800.228.4277 ext. 1664.

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