No navigation system symbolizes old-school technology more than the nondirectional beacon. But as NDBs fade from the scene in most U.S. airspace, they still play key navigational roles in Alaska, making the FAA’s reluctance to invest in their upkeep a cause for pilots’ concern.
Most NDBs and all instrument approaches based on them will likely be gone from the National Airspace System by 2030. To keep the disappearance of NDBs from undermining Alaska’s beacon-dependent colored airways, several aviation organizations will soon join with the FAA as part of a working group to develop a new en route structure built on a foundation of GPS-based airways called T-routes.
The working group, consisting of AOPA, the Alaska Airmen Association, the Alaska Air Carriers Association, the National Business Aviation Association, the FAA, and other stakeholders, will begin meeting in May to review Alaska’s colored airways and identify where T-routes will be needed.
The NDB-based routes are referred to as colored airways because they “are identified as green, red, amber, or blue,” according to the Aeronautical Information Manual.
The urgency of the situation is revealed in a key statistic: As of August 2018, approximately 25 percent of NDBs in the Alaska en route structure were out of service, according to a review of notices to airmen.
Also, a study showed that in many cases, NDB-based routes offer lower minimum en route altitudes than satellite-based substitutes—meaning that aircraft without icing protection could be forced to fly at higher minimum en route altitudes, at higher risk, on some T-routes. AOPA is working to ensure the new T-routes in Alaska offer equally good or better en route altitudes.
The aviation organizations requested the route modifications last fall because the FAA, with little public notice, had dialed back efforts to repair and maintain NDBs with airway functions.
“We believed action was needed to mitigate the effect of what was quickly becoming an unusable en route structure,” said Rune Duke, AOPA senior director of airspace, air traffic, and aviation security. “The FAA agreed, and funded the effort to address this safety issue.”
Pilots interested in suggesting how the NDB-based routes can be enhanced with new, extended, or modified T-routes, adjacent to or overlying all existing colored airways in Alaska, should email their recommendations to AOPA. With colored airways being phased out when the supporting NDBs fail, AOPA must identify what route structure is needed in the state to support modern general aviation operations.
Whether a pilot flies under VFR or IFR, all that’s needed is to include a beginning point and ending point of the route, or an explanation that the recommendation is to overlay a T-route on an existing colored airway.
There will be additional opportunities for pilots to provide feedback in April through a series of webinars. Later, it will be possible to submit formal comments to the FAA with routing suggestions. Pilots should email AOPA to be sure to be added to the webinar attendance list.
When making their “time sensitive” request to the FAA to switch Alaska’s airways away from dependency on NDBs, the aviation organizations noted that their goal was consistent with an RTCA Tactical Operations Committee’s Performance Based Navigation Route Structure recommendation that states, “The FAA should evaluate all Colored Airways for: (a) direct replacement (i.e., overlay) with a T-Route that offers a similar or lower MEA; (b) the replacement of the colored airway with a T-Route in an optimized but similar geographic area while retaining similar or lower MEA; or (c) removal with no route structure (T-Route) restored in that area because value was determined to be insignificant.”
Duke also noted that the proposed evaluation would be appropriate given fleet data included in an AOPA white paper indicating that the majority of the IFR aircraft fleet has become GPS-equipped; 85 percent use GPS as the primary IFR en route navigation source; 73 percent use GPS substitution exclusively to navigate colored airways; and more than 90 percent of IFR flight plans in Alaska include an RNAV or GNSS aircraft equipment suffix.
“We believe this request for T-Routes is exigent to mitigate the forecasted decommissioning of NDBs and cancellation of Colored Airways in Alaska,” the group said in its submission to the FAA.