Date: 201206
Local time of day: 0601-1200
Location: ADS.Airport, TX
Flight conditions: VMC
Weather elements / visibility: 13
Light: Daylight
Aircraft: Small Aircraft
Operator: FBO
Operating under: Part 91
Flight plan: None
Mission: Training
Flight phase: Initial Approach
Airspace: Class D ADS
ATC / advisory: TRACON D10
Reporter organization: FBO
Reporter function: Instructor; Pilot Flying
Reporter qualification: Flight Crew Commercial; Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Flight Instructor
Human factors: Confusion; Workload; Communication Breakdown
Anomaly: ATC Issue All Types
Result: Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Procedure; Airspace Structure
Primary problem: Procedure

Narrative: I was returning to ADS from a training flight with a student and was in contact with Dallas Fort Worth 'Regional Approach' TRACON. I was conducting the flight under VFR at the time. I was in contact with Regional Approach because ADS is a unique Class D airport in that they require all pilots to contact Regional Approach for sequencing into the airport. At no time was I ever in the Class B airspace; however it is still required for VFR pilots to contact Regional Approach. This requirement is explicitly mentioned in all of ADS's ATIS broadcasts. After contacting Regional Approach; I was assigned a squawk code and given instructions to enter a left base for Runway 15. It should be noted that the Approach Controller was extremely busy from the point I made contact with him and the point where he switched me over to Tower. After being assigned a squawk code I was getting closer and closer to ADS as I was flying directly to the field to enter a left base for Runway 15. The Approach Controller never replied back to my squawk code with the standard procedure of identifying me as a radar contact and giving me my position. As I got closer and closer to ADS Class D airspace; I became concerned that I would enter the airspace without being switched over to Tower and having the chance to identify myself and have them read back my call sign. All that is required for an aircraft to enter Class D airspace is a readback of the aircraft's callsign by the air traffic controller in the ATC Tower. This is where my confusion began. I was not clear on whether the TRACON Controller's readback of my callsign allowed me to enter Class D airspace since that airspace does not belong to the TRACON Controller. Because of my concern I tried numerous times to clarify with the TRACON Controller whether or not I could enter the Class D airspace without talking to the Tower Controller. In my previous experience operating to and from ADS; I had always been switched to tower prior to entering Class D airspace. The TRACON Controller was too busy and did not respond for clarification. I decided that I would make a 360 turn at my current position about one mile outside of the Class D airspace boundary to ensure that I did not enter any airspace without acknowledgement. I announced that intention to the TRACON Controller and again received no response. The TRACON Controller finally acknowledged me as I was rolling out of my 360 degree turn and announced that I should enter a left base for Runway 15. About two miles outside of the Class D airspace I was finally told to contact the Tower and I landed without further confusion or incident. I believe that this set up of contacting Regional Approach prior to contacting ADS Tower provides a confusing and non-standard situation to pilots operating under VFR to ADS. Unlike a Class C airport or a Class D airport with TRSA; the VFR pilot assumes he must have his call sign acknowledged by the Class D ATC Tower prior to entering its airspace. There is no such guidance for the type of setup at ADS. The only information about this practice is included in the ATIS broadcast and is limited to the phrase 'all VFR arrivals contact Regional Approach on 124.25 prior to contacting Tower.'




Synopsis: Small aircraft Instructor Pilot; unable to obtain handoff from a busy Regional Approach Controller for entry into the ADS Class D airspace; executed a 360-degree turn outside of the airspace before being cleared to enter a left base for Runway 15. Pilot was not handed off to the Local Controller until two miles inside the Class D airspace and noted the lack of information available as to the proper airspace entry procedure for this airport.