Updated June 17, 2019

NBAA continues to monitor the ongoing service disruption affecting certain Collins Aerospace (formerly Rockwell Collins) GPS receivers, and operators should also familiarize themselves with how those systems work on their aircraft, what capabilities are actually affected and how the disruption may impact their operations.

According to Collins Aerospace, the affected GPS receivers are GPS-4000S part number 822-2189-100 and GLU-2100 part number 822-2532-100, used in several business aircraft types equipped with Collins Pro Line 4, Pro Line 21 and Pro Line Fusion avionics.

On Sunday, June 16, 2019, at 00:00 the U.S. GPS Constellation update was released, which returned many Collins GPS-4000S units to an operational state. For more information on this issue, review Operator Bulletin OPSB 0195-19, available on the Collins Aerospace Publications and Training Online Index.

“This is a rapidly evolving situation, and the NBAA Air Traffic Services (ATS) team is seeing the nationwide operational effects from this disruption from the FAA’s Air Traffic Control System Command Center,” said Heidi Williams, NBAA director for air traffic services and infrastructure. “We continue to be engaged with the FAA, Collins Aerospace, aircraft manufacturers and other affected stakeholders to determine the best route forward in resolving these complications.”

In addition to the loss of GPS navigation capabilities, the disruption also affects automatic dependent surveillance-broadcast (ADS-B) information fed to the aircraft’s transponder. Williams noted that may lead operators to see a transponder “INOP” message and erroneously believe their aircraft are grounded.

“Although the transponder isn’t receiving ADS-B position information from the affected receiver, we’re finding that in many cases the fundamental Mode C or Mode S transponder function itself is not affected,” she explained. “In essence, the system is in conflict with itself.”

The FAA has issued two blanket exemptions for affected aircraft, one allowing continued flights via “traditional airways and/or navaids” if pilots are unable to utilize GPS navigation. The second limits operations to at or below FL280 (remaining outside of RVSM airspace) until the GPS receiver disruption and transponder issues are resolved and those systems are returned to full service.

In the interim, operators should perform a detailed assessment of the impact from the GPS disruption to their flight operations, based on their mission, certificate and ops approvals. Williams also emphasized that flight crews must use the correct ICAO equipment codes when filing flight plans, rather than relying on their aircraft’s default ICAO flight plan codes

“It’s critically important that flight crews properly communicate their current navigation, communication, and surveillance equipment capabilities to ATC in order to ensure safe operations,” she added.

Service-related inquiries may be directed to Collins Aerospace at avionicssupport@collins.com or by calling 319-295-5000. Operators should include aircraft type, GPS/GLU model number, GPS/GLU part number, serial number and modification status.