In the months leading up to the looming ADS-B Out mandate, many operators were scrambling to get their aircraft compliant. Those with Collins Flight Management Systems (Pro Line IV, Pro Line 21, and Pro Line Fusion) upgraded their GPS-4000 sensors to the new, WAAS-compliant GPS-4000S, part number 822-2189-100. These upgrades may have also been done during LPV approach capability upgrades on Collins FMC-X000 systems.

In June of 2020, operators of aircraft equipped with these GPS sensors were forced to ground their aircraft during GPS Week 128 (June 12 thru 19, 2020) due to the potential hard failure of these sensors during that week. Some of those operators that did power up their aircraft during that week were forced to send in their sensors to Collins for reboot. The issue corrected itself after June 19, with the issuance of the new GPS Almanac.

For those aircraft with 822-2189-100 GPS-4000S sensors still installed, the next date there could be an impact due to this issue will be June 2023 unless prior corrective action is taken.

That corrective action will be to exchange the current GPS-4000S sensor with part number 822-2189-101. This is a no-charge component upgrade through Collins approved by their Approved Model List (AML) STC. Labor will be minimal as there are no wiring changes and only a Maintenance Manual check-out required. The upgrade will have no effect on ADS-B Out, LPV, and TCAS STCs.

Because of the timeline of the next possible failure event, there is plenty of time to get this upgrade scheduled during your next maintenance event so as to not affect the availability of your aircraft. Currently, Collins Aerospace has exchange units ready to ship, so this upgrade can be done during the next 12-month inspection, with prior scheduling. If that should change in the future, prior planning will be required to send your units in for the no-charge upgrade.

This issue is not present on GPS-4000S part numbers 822-2189-004 and 822-2189-010.