Resolving a database dilemma

As you’ll soon discover, however, departing as cleared requires understanding and correlating information from several key sources, including the Aeronautical Information Manual and advisory circulars, and the approved flight manual supplement (AFMS) and pilot guide for your GPS navigator.

The SCAPO SEVEN is a conventional DP that requires only a VOR receiver, but you noticed a notam in the preflight briefing that renders the procedure “NA EXCEPT FOR ACFT EQUIPPED WITH SUITABLE RNAV SYSTEM WITH GPS, UBG VOR/DME OUT OF SERVICE.”

That restriction shouldn’t be a problem, because your panel includes a Garmin GTN 750, which qualifies as a “suitable RNAV system” according to AIM 1-2-3 and the AFMS that the avionics shop provided when you installed the GTN. That section of the AIM and its fraternal twin, AC 90-108, also confirm that you can use the GTN to fly the SCAPO SEVEN, because you can substitute GPS for VOR radials, five-letter fixes, and DME, even when navaids are out of service.

With the propeller turning, you read back the clearance and start to load the route in the GTN, only to discover that the SCAPO SEVEN isn’t in the database, probably because of a quirk in how some DPs are coded. Now what?

You recall admonitions that require loading IFR procedures by name from the database. For example, AIM 1-1-17 says that “All approach procedures to be flown must be retrievable from the current airborne navigation database....The system must be able to retrieve the procedure by name from the aircraft navigation database, not just as a manually entered series of waypoints.” AC 90-108 and the AFMS include similar language. But the SCAPO SEVEN is a departure, not an approach. And the notam seems like a blessing—indeed a directive—from the FAA to use your GTN to comply with the clearance.

The section “IFR Use of GPS” in AIM 1-1-17 hints at a solution, but it apparently still leaves you in IFR limbo. Under “Departures and Instrument Departure Procedures (DPs),” the AIM says, “The navigation routes [must be] contained in the database in order to fly published IFR charted departures and DPs,” while also noting that “Certain segments of a DP may require some manual intervention by the pilot, especially when radar vectored to a course or required to intercept a specific course to a waypoint. The database may not contain all the transitions or departures from all runways and some GPS receivers do not contain DPs in the database.”

The AFMS for the GTN, however, goes further. Section 2.4 of that document explains that “Whenever possible, RNP and RNAV routes including Standard Instrument Departures (SIDs)…should be loaded into the flight plan from the database in their entirety…[But] selecting and inserting individual named fixes from the database is permitted, provided all fixes along the published route to be flown are inserted.” Later, in Section 2.8 Navigation Database, the AFMS adds that “GPS/SBAS based IFR enroute, oceanic, and terminal navigation is prohibited unless the flight crew verifies and uses a valid, compatible, and current navigation database or verifies each waypoint for accuracy by reference to current approved data.”

In other words, if you can verify the required waypoints against a current chart, you can build a conventional departure. The AFMS specifically prohibits manual entry of fixes only when loading an approach.

So, to fly the SCAPO SEVEN and comply with your clearance and the notam, you must add the appropriate fixes by name to your flight plan. The best technique is to create a leg between UBG and SCAPO, so that after the climb via the charted headings you can join and fly the UBG 334 radial to SCAPO (a fix also identifiable via the BTG 250 radial or the IPDX localizer). Or you could press direct and set a course of 334 to SCAPO.

Those techniques—creating and activating a leg or specifying a course direct to a fix—are often misunderstood and infrequently practiced skills. You can learn about them in the user guide for your avionics, but it’s best to practice the steps with simulations, such as the free Garmin PC Trainer Suite and Garmin iPad avionics trainers. Even better, run through this and similar scenarios in an aviation training device (ATD) with an instructor.

If the multiple references and FAA-speak seem daunting, don’t despair. The FAA expects to release AC 90-119 Performance-Based Navigation Operations before the end of 2025. That AC, currently in final review and coordination, consolidates and clarifies guidance about using GPS (the only “suitable RNAV system” in most light GA aircraft) that is now scattered among several ACs, the AIM, and other handbooks. In particular, if the final version of AC 90-119 reflects the drafts released for public comment in 2021 and 2023, pilots and instructors will welcome clear explanations of how you can use GPS as an alternate means of navigation or as a substitute for conventional navaids, whether you’re climbing out on a departure, cruising en route, descending on an arrival, or flying an approach. Check back here for a detailed review of AC 90-119 when it is published.

Bruce Williams is a CFI. Find him at youtube.com/@BruceAirFlying and bruceair.wordpress.com.