Citation 560XL/XLS: Keeping Avionics Online During Engine Startup

Contributed by Chuck Zahnow, Airframe Tech Rep

The normal engine startup sequence for Citation 560XL aircraft removes power from the avionics system, causing it to drop offline. The reason for this is the avionics are isolated from the start system. SB560XL-24-14R2 allows the avionics to stay online by using the APU generator during engine start.

This service bulletin (SB) is a really great modification for the airplane, but there are still aircraft that have not been modified and time is running out. Cessna warranty covers all affected aircraft until February 2012. If the SB has not been accomplished yet, it is not too late.

The modification requires removal of the aft J-box and access to the aft baggage floor and cockpit PCB box. The best option for this to be done is at a major inspection, since it won’t add downtime and the inspection improves access to these areas. If the SB is done alone, it will take about one week.

If there is not a major inspection to be done prior to February, that is not an issue. We have been able to get this done and get it covered by warranty, including the hours of access.

Affected serial numbers include:

  • 560XL: 5002-5372 (if APU is installed)
  • 560XLS: 5501-5799 (all)

If your aircraft is affected and you haven’t done this SB, I strongly recommend you get it done before the warranty expires.

Duncan Aviation is a Cessna authorized service center for Citation 500 and 600 series. For a list of our Citation service capabilities, technical support and service sales contacts, please visit

Chuck Zahnow serves as an Airframe Technical Representative at Duncan Aviation’s Battle Creek, Mich. (BTL) facility, specializing in Citation and Hawker aircraft. He began his career in aviation in 1996.

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