Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor
Flight Crew Last 90 Days 200; Flight Crew Total 25000; Flight Crew Type 3000
Training / Qualification
ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Human Factors; Procedure
During approach to ATL we were vectored out of the Class B airspace and told we would re-enter in 5 miles. The preceding aircraft was also vectored out of the Class B. The ILS was functional and all aircraft were on IFR  flight plans. I believe this was done by ATC in order to assign visual approaches. Part 121 IFR traffic should never be vectored out of the Class B. This extremely unsafe practice defeats the entire purpose for having Class B airspace. VFR traffic is excluded allowing the traffic to the Class B anchor airport separation from each other. Class B airspace (then TCA) came into being due to the midair collision causing great loss of life in a similar situation. It is apparent ATC believes the requirement for aircraft operating within the Mode C veil and under Class B airspace to have ADS-B Out capability allows them to see all aircraft. This is simply not true. There are many aircraft types which can legally operate in this airspace without ADS-B Out capability. Gliders; ultralights and any Part 91 aircraft never having had an electrical system are some of the types. A midair collision between an airliner on an IFR clearance and one of these VFR types operating legally in the airspace would be catastrophic. The presence of a Part 91 aircraft required to have ADS-B Out capability but with an ADS-B equipment failure unknown to the pilot in command would be another possibility. All of this is easily avoidable. Keep the traffic requiring the Class B confined to that airspace as ATC is supposed to do. Do not have airliners outside of their protected airspace infringing on airspace where other traffic may be. The price of an error on the part of a controller; pilot or equipment is simply too high. We should have been kept in the Class B and given clearance to fly the ILS we were told to expect and for which we were briefed and prepared.
Air carrier Captain reported ATL TRACON vectors commercial aircraft outside of Class B airspace on approach.