Cessna 150
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Commercial
Flight Crew Last 90 Days 39.7; Flight Crew Total 12466; Flight Crew Type 1890
Communication Breakdown; Confusion; Human-Machine Interface; Situational Awareness
ATC Issue All Types; Airspace Violation All Types
Air Traffic Control Issued Advisory / Alert
ATC Equipment / Nav Facility / Buildings; Procedure; Human Factors; Chart Or Publication
A routine flight was made to SDM. This was one of nine flights performed to SDM for the month; tracking basically the same flight path as the previous flights. A Garmin 430 (certified for IFR flight with a current card) with a moving map display was programmed and activated to go GPS direct to SDM; the VOR (POGGI-109.8) radial 350 (170 heading). Upon departing we proceeded southbound to SDM via the eastern side over Sweetwater Reservoir. The course was flown underneath Class Bravo Airspace with the floor varying between 4;800 MSL and 1;800 MSL and 300 MSL. At all the times the aircraft was operated below the floor of class Bravo Airspace. Upon landing at SDM; the Controller asked that I contact the Approach Control Supervisor. I complied and contacted him via phone. I informed Approach Control that I remained clear of the Class Bravo Airspace at all times and had checked my position via GPS and VFR waypoints to ensure an incursion into the airspace would not and did not occur. As a result of events of the day; I retraced the flight later that evening with a Class Bravo clearance. Upon passing north of Sweetwater Reservoir; a VFR waypoint; and the point at which the floor of Class Bravo Airspace changes from 1;800 MSL to 3;000 MSL; the Controller was asked the verify the floor of the airspace above. The Controller stated 1;800 MSL. I verified my position via GPS and the VFR waypoint (Sweetwater Reservoir) and confirmed that pursuant to the marking of Class Bravo Airspace on the VFR chart; San Diego that the floor of Class Bravo Airspace indicated to be 3;000 MSL at that position. The overlay of Class Bravo Airspace as shown on the VFR terminal chart; San Diego with respect to ATC radar and GPS receiver should be verified.
When advised by Approach Control he had violated the floor of the San Diego Class B when transiting to SDM; the pilot of a GPS equipped C150 advised he had not and suggested the accuracy of local area charts compared to ATC radar be examined.