When blocking airspace, what is the designation for the track you start in the shelf?

When blocking airspace, what is the designation for the track you start in the shelf?

• A. Start a track named AOAXXX with XXX as the lower altitude
• B. Start a track named AOBXXX with XXX as the upper altitude
• C. Use an existing track
• D. Do not create any track

Answer: (B)

When you block airspace, you’re creating a vertical block in the shelf, which is a defined airspace layer with a ceiling. The track you start in that shelf is named with a prefix that indicates it’s a shelf track and you append the upper altitude of that shelf. This makes the track’s vertical extent clear: the designation communicates the ceiling up to which the track applies. That’s why the correct approach is to start a shelf track named AOBXXX, where XXX is the upper altitude. Using the lower altitude in the name would misrepresent the shelf’s ceiling, and starting with an existing track or not creating a track would fail to properly enclose the blocked airspace.

When you block airspace, you’re creating a vertical block in the shelf, which is a defined airspace layer with a ceiling. The track you start in that shelf is named with a prefix that indicates it’s a shelf track and you append the upper altitude of that shelf. This makes the track’s vertical extent clear: the designation communicates the ceiling up to which the track applies. That’s why the correct approach is to start a shelf track named AOBXXX, where XXX is the upper altitude. Using the lower altitude in the name would misrepresent the shelf’s ceiling, and starting with an existing track or not creating a track would fail to properly enclose the blocked airspace.