King Air Summer 2008

• Radar—Use it or Lose it
• Service Letter Update for Propellers
• Think About Your Batteries

Radar—Use it or Lose it

— Rick Conner

A key component of the Primus 300SL RADAR is the magnetron. Duncan Aviation has learned that magnetrons used in Primus 300SL radar units are no longer in production. We also believe the existing magnetrons have a limited shelf life and failure rates will increase with time.

What can operators do about this situation? The best option is to help your Primus 300SL last as long as possible. Duncan Aviation recommends turning it on at least once every month to keep it “in shape.” If/when it fails, magnetrons can be found. However, the parts/repair costs may steer you toward an upgrade. There are several upgrade options that add reliability and functionality.

For details about how to help your radar last longer and possible upgrade paths, we recommend calling any Duncan Aviation satellite shop or Dan Magnus at 800.228.1836 ext. 4217.

Service Letter Update for Propellers

— Bob Finke

"Reactionless mode," a specific vibratory resonant condition, cannot be felt by the flight crew. Left uncorrected, it could cause damage to the propeller. Illustration courtesy of McCauley Propeller Systems © Copyright 2006.

Duncan Aviation’s Component Solutions advises that King Air Operators Hartzell Service Letter 254, McCauley Service Letter 2005-07 and the FAA’s SAIB NE-06-13 are all more than two years old. It is important for turboprop operators that have propellers with four or more blades to verify that their minimum propeller RPM is adjusted properly. If your minimum propeller RPM is found to be in the restricted range, you need to refer to the applicable service information to determine the proper corrective action. The specific vibratory resonant condition known as “reactionless mode” (see animation above) cannot be felt by the flight crew and could be causing damage to the propeller unless corrected.

For more information about the proper corrective action needed for these service letters, please contact Bob Finke at 800.228.1836 ext. 1517.

Think About Your Batteries

— Michael Craft

The extremes of weather can quickly, and often without warning, shorten the life of your main ship batteries. Standard Nicad batteries require a high level of maintenance and are extremely costly to keep in service. Aircraft batteries that are commonly used today often fail without much warning. Extremely hot summers and cold winters can speed up the deterioration of these lead acid batteries.

There are options today that incorporate much advanced technology. New sealed lead acid battery technology developed by Securaplane provides dependable service from -55C to 75C. Cranking amps are very important within these ranges because no one wants to be left sitting on the ramp with a failed battery. Additionally, operators save money because of fewer “in service” maintenance requirements, lowering labor and service costs and downtime.

Duncan Aviation Component Solutions is recommending that operators switch to the new sealed lead acid battery technology at their earliest convenience. These batteries can save operators money and include many features.

For additional technical or sales information, please contact Component Solutions at 800.228.1836 and ask for Jerry Cable at ext. 8112 or Bob Tooker at ext. 4205.

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