My final thoughts on this thread. The original scenario in question was H60 vs H60 vs H60 in the pattern. When working a 100% helicopter operation things are different. That is why the 7110.65 has a special section for helicopter operations. You are able to break the airport up into numerous landing areas. A couple of landing area examples would be breaking up and assigning portions of runways or Sod areas. When doing this with helicopters everything becomes simultaneous. You must keep in mind that the only helicopter that could be cleared for the option would be the #1 helicopter and the helicopters behind the #1 going to an assigned landing area that could be in conflict with the #1 helicopter such as a portion of the runway behind the #1 need to be cleared to land. You never want the #2 helicopter to do a low approach over the #1 guy ahead of him who decided to do a stop and go. That would not be legal and not even Visual Separation would get you out of that when the #1 guy started climbing into the #2 guy.
With all that being said, when you are mixing helicopters and airplanes things do change. Such as, when the succeeding aircraft is a helicopter, visual separtaion may be applied in lieu of using distance minima. The original post was not on mixing airplanes and helicopters, it was on running 3 H60 helicopters around the pattern and staying legal. Chapter 3 section 11 of the 7110.65 was the area of concern and where the answer to the question is found. Of course the aircraft needed to be sequenced and separtared by the 200ft minima either by assigning landing areas at least 200ft from other helicopters and not having conflicting courses or instructing the pilot to land 200ft from the helicopter that he is following. Keeping in mind that the #2 helicopter is cleared to land and only cleared to land unless the #1 helicopter has exited the landing area ahead. Working a large volume of helicopters can be a ton of fun if it is done right.
This is a wonderful site if it is used right. I have just been an observer over the past years and this subject and a couple others just started to catch my attention a bit more. This site would be better served if people start making sure that they are 100% correct when giving advise. You don't have to answer every thread. The thread that caught my attention most was an aircraft being instructed to follow another aircraft on a Visual Approach. It was said by a contributor that you had to tell the #2 aircraft to Maintain Visual Separation from that traffic, follow that traffic to the airport, Cleared Visual Approach Runway 35L. If I had to say that to every aircraft that I was sequencing in a busy terminal environment I would never stop talking and the pilots would never have the chance to put in a request or try to declare an emergency on a nice VFR day.
My point is the answer should be spelled out nice and clear. When visually following a preceding aircraft, acceptance of the visual approach clearance constitutes acceptance of pilot resposibility for maintaining a safe approach interval and adequate wake turbulence separation (AIM 5-4-23.d). Our job as ATC is to issue the Visual Approach clearance. For example (Call sign) (control instructions as required/follow the Boeing 757 to the airport) Cleared Visual Approach Runway 35L.
Thank you for your time and I hope that we can all work together to provide the best ATC service possible to our users, the pilots.