Groups Warn Loss of SID Waypoints in FMS May Lead to Departure Deviations

June 29, 2022

A recent spate of pilot deviations on the RUDDY 6 SID procedure at New Jersey’s Teterboro Airport (TEB) has led NBAA and other stakeholders to advise further caution to flight crews when setting up their aircrafts’ flight management systems (FMS) to fly a SID.

“We’ve seen more than a half-dozen issues [on RUDDY 6] over the past couple of weeks, which clearly shows a need to dig in deeper into what may be going on here,” said Heidi Williams, NBAA senior director for air traffic services and infrastructure.

According to the Teterboro Users Group (TUG) the issue appears to lie in a limitation in the practical application of CPDLC DCL (Controller-Pilot Data Link Communications – Departure Clearance) within the U.S.

“When issued a CPDLC DCL other than ‘cleared as filed,’ the clearance will include a loadable route, which the crew must insert and activate,” TUG stated. “This loaded route will not contain the assigned SID. If the runway and SID had been previously loaded into the FMS, this action may retain the runway and associated performance information, but will drop the SID and its associated waypoint list segments and constraints.”

Flightcrews face a potential deviation on departure unless they reinsert and activate the SID for which they’ve been cleared. This limitation appears to be specific to the FAA Data Comm system, TUG added, impacting all users and all FMS regardless of manufacturer.

Further, there appears to be “no easy solution” to rectify the issue, noted Rich Boll, chair of the Airspace, ATC and Flight Technologies Working Group of the NBAA Access Committee, due to the runway-independent nature of U.S. SIDs.

“In Europe and elsewhere in the world, SIDs are runway-specific,” he explained. “This issue wouldn’t occur under that system, though at TEB alone that would mean we’d now have four SIDs instead of one. It’s a difficult problem to address.”

The FAA is working with stakeholders to identify potential mitigations for the issue. In the meantime, Boll reiterated the importance of operators verifying they have the correct information uploaded to their FMS prior to departing on RUDDY 6 and other SIDs at airports across the country.

“As one who has fallen victim to a re-route when the SID was deleted and didn’t realize it, it’s an easy trap to fall into,” he said. “I’m probably more familiar with this subject than most, and I should have known better, yet I still made the mistake. Those not aware will fall into the trap more easily.”