Automatic Dependent Surveillance-Broadcast in Retrofit Spacing trial
Albuquerque Air route traffic control center
MARCH 1, 2023 until november 6, 2023
Albuquerque Air Route Traffic Control Center (ZAB) has been conducting a trial for Automatic Dependent Surveillance-Broadcast (ADS-B) In Retrofit Spacing (AIRS) since November 7, 2022. The trial is specific to American Airlines (AAL) A321 aircraft. AAL A321s may space themselves behind a lead aircraft with ADS-B Out using avionics-command speed control after controller-specified in trail spacing is issued. This is known as Initial-Interval Management (I-IM).
Air Traffic Control instructions for IM may include callsigns of non-participating aircraft while an Air Traffic Clearance is being issued to participating aircraft. No action is to be taken by non-participating aircraft during these trials.
ADS-B In Retrofit Spacing (AIRS) procedures at zab
- IM procedures are defined for ZAB controllers and qualified aircrews to utilize avionic command speeds to conduct operations within ZAB airspace. This operation allows flight crews to accept speed commands from the IM avionics to achieve controller issued Assigned Spacing Goals (ASG).
- IM operations in ZAB airspace:
(1) IM clearances will either have a crossing instruction or a maintain instruction.
Examples:
“AAL755 cross SLIDR (eight miles/eighty-two seconds) behind UAL345”
“AAL755 maintain (eight miles/eighty-two seconds) behind UAL345”
(2) The flight crew of the Trail aircraft will check on frequency and advise they are spacing behind the Lead aircraft. The Lead aircraft may be a non-participating aircraft and no action is necessary. Example: “AAL457 checking on FL330 spacing behind UAL587”
([TCAB1 ZAB ZAB530], [March 1, 2023])
