AIM ¶ 3-5-6 — Terminal Radar Service Area
AIM 3-5-6 explains Terminal Radar Service Areas (TRSAs): non-Part 71 airspace, voluntary VFR participation, Class D primary airport, and chart depiction.
In Plain English
A Terminal Radar Service Area (TRSA) is a leftover from the original Terminal Radar Program. Because TRSAs were never created through the rulemaking process, they are not regulatory airspace — they don't appear in 14 CFR Part 71, and there are no TRSA operating rules in Part 91. As a result, TRSAs do not fit into any of the standard U.S. airspace classes (A, B, C, D, E, or G).
Key points to remember:
- The primary airport inside a TRSA is Class D airspace.
- The rest of the TRSA overlies other controlled airspace, typically Class E starting at 700 or 1,200 feet AGL, used to transition between the en route and terminal environment.
- Pilot participation is voluntary for VFR pilots, but ATC encourages you to contact radar approach control to receive TRSA Services (additional radar services like sequencing and separation).
- On VFR sectional and terminal area charts, the TRSA boundary is drawn with a solid black line with altitudes for each segment, and the Class D portion uses a blue segmented (dashed) line.
Operationally, flying through a TRSA is a great opportunity to use radar advisories — but you're not legally required to participate.
AIM Source Text
FAA AIM ¶ 3-5-63-5-6. 3-5-6. Terminal Radar Service Area (TRSA)
Background. TRSAs were originally established as part of the Terminal Radar Program at selected airports. TRSAs were never controlled airspace from a regulatory standpoint because the establishment of TRSAs was never subject to the rulemaking process; consequently, TRSAs are not contained in 14 CFR part 71 nor are there any TRSA operating rules in 14 CFR part 91. Part of the Airport Radar Service Area (ARSA) program was to eventually replace all TRSAs. However, the ARSA requirements became relatively stringent and it was subsequently decided that TRSAs would have to meet ARSA criteria before they would be converted. TRSAs do not fit into any of the U.S. airspace classes; therefore, they will continue to be non-part 71 airspace areas where participating pilots can receive additional radar services which have been redefined as TRSA Service. TRSAs. The primary airport(s) within the TRSA become(s) Class D airspace. The remaining portion of the TRSA overlies other controlled airspace which is normally Class E airspace beginning at 700 or 1,200 feet and established to transition to/from the en route/terminal environment. Participation. Pilots operating under VFR are encouraged to contact the radar approach control and avail themselves of the TRSA Services. However, participation is voluntary on the part of the pilot. See Chapter 4 , Air Traffic Control, for details and procedures. Charts. TRSAs are depicted on VFR sectional and terminal area charts with a solid black line and altitudes for each segment. The Class D portion is charted with a blue segmented line.
Oral Exam Questions a DPE Might Ask
Q1Is a TRSA regulatory airspace, and what airspace class is it?
Per AIM 3-5-6, a TRSA is not regulatory airspace — it was never subjected to rulemaking, so it is not in 14 CFR Part 71 and has no operating rules in Part 91. It does not fit into any U.S. airspace class. The primary airport within the TRSA is Class D, and the surrounding area overlies other controlled airspace (typically Class E at 700 or 1,200 feet).
Q2Is pilot participation in TRSA Services mandatory?
Per AIM 3-5-6, participation is voluntary. VFR pilots are encouraged to contact radar approach control to receive TRSA Services, but they are not required to do so.
Q3How is a TRSA depicted on a VFR sectional chart?
Per AIM 3-5-6, TRSAs are charted with a solid black line showing the boundary along with altitudes for each segment, while the Class D portion (the primary airport) is depicted with a blue segmented (dashed) line.
Related Paragraphs in AIM Chapter 3