If you are one of the many operators who have the Collins Aerospace GPS-4000S-101 as part of your current flight deck equipment, the following information may be useful to you.

There has been a second revision of Service Bulletin (SB) GPS-4×00()-34-515 for the GPS-4000S Global Positioning System.  This service bulletin is recommended to prevent significant operational disruptions.

Affected aircraft and systems include, but are not limited to:

• Bombardier Challenger: The Challenger 300, Challengers 604 and 605 equipped with the Pro Line 21 or Fusion
• King Air: The King Air B200 and 350 equipped with the Pro Line 21 or Fusion avionics system
• Hawker: The Hawker 700, 800XP, 850XP, 750, and 900XP equipped with the Pro Line 21
• Embraer Legacy: 450, 500 and 550 equipped with Fusion
• Learjet: The Learjet 60XR equipped with the Pro Line 21 avionics system
• Gulfstream: The Gulfstream 150 and 200 equipped with Pro Line 21 or Proline 4
• Falcon: 50EX, 2000, and 2000EX equipped with the Pro Line 21
• Citation CJ: The CJ1+, CJ2+, CJ3, and CJ4 equipped with the Pro Line 21
• Citation 560 Encore+: The Encore+ equipped with the Pro Line 21
• Citation 560 XLS+:  The 560 XLX+ equipped with the Pro Line 21

Collins Aerospace is recommending the software update to bring -101 to -102, then remove and replace the identification plate.  The expected benefits of the update include improved availability of LPV, navigation in SBAS Region, and robustness to RFI.  The implementation of this service bulletin is total and permanent.