So you have ADS-B installed in time for the mandate that took effect Jan. 1, 2020, requiring ADS-B Out in certain controlled airspace. But are you sure it’s working properly?
The mandate requires aircraft owners to use equipment meeting the requirements of FAR Part 91.225 and 91.227 when flying in what the FAA is calling “rule airspace.”

The technical requirements that establish the performance requirements for ADS-B equipment were finalized by the FAA in 2011.
In 2018, the FAA developed “Exemption 12555,” which addresses performance requirements of some GPS receivers used to support ADS-B equipment.
Unfortunately, for some aircraft owners, the performance of their GPS receivers falls below the requirement stated in the rule.
The good news? The FAA is allowing continued use of this GPS equipment to meet the rule requirements when backup FAA surveillance is available, according to officials with the National Business Aviation Association.
This exemption, which expires on Dec. 31, 2024, “is not a time extension for compliance with the ADS-B rule for aircraft, nor a general relaxation of the rule performance requirements,” NBAA officials advise.
“In other words, this exemption does not extend the compliance date for ADS-B transponder equipment meeting current standards,” they explain.
A small number of aircraft with pre-2011 ADS-B equipment — or “Version 1” — will need to use the FAA’s ADS-B Deviation Authorization Preflight Tool (ADAPT) to seek permission on a flight-by-flight basis to operate in rule airspace.
This resource is also available for aircraft owners who haven’t had a chance to equip yet — or who don’t plan to, but want to make a flight requiring they enter rule airspace.
Exemptions will be granted online at FAA.gov/NextGen/EquipADSB/Adapt. That page also includes a video that walks you through how to fill out the ADAPT form.
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AvWeb explains it well
I’m still confused. It appears to me that the Class C Airspace has a floor around Anchorage. As long as we stay under the class C we should be able to come and go into the Class D Airports associated with Anchorage. Please correct me if I’m wrong