Widebody Transport
Flight Crew Air Transport Pilot (ATP)
Workload; Communication Breakdown; Human-Machine Interface
Deviation - Speed All Types; Deviation / Discrepancy - Procedural FAR
General None Reported / Taken
Aircraft; Airspace Structure; Human Factors; Procedure
We were being vectored from the north for a visual approach to Runway 27 at MEM. During the descent from 4;000 FT to 3;000 FT the  Controller told us we were re-entering Class B airspace and that we had been out of Class B airspace for about 1 mile.  The threat was (and continues to be) the lack of a practical; real-time means for pilots to detect where they are in relation to the base of Class B airspace around an airport. It is totally impractical (too attention consuming during a critical phase of flight) to try to monitor on the EFB the aircraft's position relative to the varying radials; DMEs and altitudes.  Suggestions from a piloting standpoint:  1) Slow to 200 KTS whenever approaching a Class B airspace. The downside of this approach is increased delays at airports; as Class B starts a considerable distance from airports.  2) Never descend before it is required to make altitude restrictions on the approach. The downside here is the increased potential for being high/fast if there is any misjudgment.  From an automation standpoint; enhance automation; showing Class B airspace on the PFD or; perhaps better (to avoid excessive data on the PFD); showing aircraft location on a moving map on the Class B page of the EFB.  From a regulatory standpoint: simplify the speed requirement; perhaps to be similar to that used by Canada (200 KTS if below 3;000 AGL within 10 miles of an airport).
Wide Body Aircraft Captain is informed by ATC aircraft is reentering Class B after having been out of it. Reporter comments on the difficulty of monitoring Class B in the flight deck with current instruments.