Originally Posted by
Easy Street
Class B is not used in Europe, which is probably where your confusion comes from. The starting point in Class B is that ATC is responsible for separating all traffic, including VFR from VFR, so the "type of service" is not really a relevant concept. You must talk to ATC and you must do what they say, regardless of flight rules.
How ATC apply that control to VFR traffic is all there in part 7-9 of the link. I suggest reading the whole part from 7-9-1, including the notes. It's not long and is quite clear, but to summarise:
A) Helos at DCA are VFR in Class B. This means they must squawk and talk (7-9-1) and follow route and altitude clearances given by ATC (7-9-2). This could be a procedural route clearance, but the controller will monitor, separate and sequence by radar (7-9-2a note 2) and may instruct aircraft to hold (7-9-2c). The separation standard is 1.5nm vs large aircraft (7-9-4b1), radar target resolution vs small aircraft (7-9-4d1) or 500ft vertical vs any aircraft (7-9-4b2 and d2).
B) The controller and pilot may agree upon visual separation (7-9-4b3 and d3), in which case the separation minima no longer apply and it becomes the pilot's responsibility to avoid collision. Throughout, traffic advisories must be given (7-9-5) and any vectors given by ATC must meet minimum altitude criteria (7-9-7) which are much higher than 200 feet.
In European terms, my paragraph A) is what you would understand as radar control and probably reflects your London experience. However, as the separation standards are difficult or impossible to achieve close to DCA, the pilot must become visual with the factor traffic, request visual separation, and be granted it by ATC in order to proceed along that part of the route. If traffic is not sighted then the controller must maintain separation by other means such as holding (vectoring being constrained by the 7-9-7 restrictions at low altitude).
The DCA airspace design didn't just incentivise pilots to report visual with traffic and request visual separation: it actively required them to, with no realistic alternative course of action besides holding. In this sort of environment, one can see how pilots might learn to respond reflexively to traffic calls by requesting visual separation to avoid their progress being impeded.
The sort of thing that happens when you don't accept visual separation when required to in Class B is well illustrated by a hotly debated event at SFO a while back. A Lufthansa aircraft refused an ATC request to accept visual separation against parallel approach traffic. Although he reported the traffic in sight, he stated that company policy did not allow him to accept visual separation at night. This left ATC no option for maintaining separation minima besides sending him around and into what some saw as a punishment hold. Lufthansa backed the pilot's decision, but changed their policy as there is no other practical way of operating into some US airports.
So,...Lufthansa will only land on a parallel runway at night, if no one is landing on the other runway? That's a tough policy at busy airports.