GWH

I'm afraid I must support the submission of my learned friend MR HD.

Comment on your previous point - if I have understood you correctly...

The proposal for full mixed-mode is that, unlike TWASS, the runways are completely independent once BOTH sides are established. That is to say that one side can be doing 3nm (2.5 not approved during parallel ops) and the other side could be doing 5, or 6 or 8 or anything you like.

Where there is an imbalance of demand to the extent that one side has airborne delay and the other doesn't the traffic will be 'managed' on to the other runway (in ways I wont go into here) so that the spare capacity is given to the delayed side, balancing the delays.

The very reason for joining at High-side glide-path plus 5nm is that it then doesn't matter what the loading is on each side; both sides will always be able to operate independently because at the time the High-side needs to descend on its glide path any traffic on the Low-side MUST be already established.

The draw back of this is that, theoretically, if you are the only aircraft for the Low-side but there is a continuous flow onto the High-side, you must still join at High-side glide path range plus 5nm - you cannot join short. (In reality of course, that is not going to happen because there will always enough demand to fill both approaches and if there weren't then the traffic would be balanced up so that there would be.) Of course the High-side can turn in short, providing it is willing to stay 1000' above any traffic on the Low-side until Loc established.

So, because your suggested blunder would always be occurring outside the High-side Glide path range (because that is where ATC will vector it to, even if number one) it will always be vertically separated from any traffic on the other side that not yet established and cannot affect the descent of the traffic that is established. Speeds difference, catch-up, overtake - no problem. This is why TWASS doesn't work; we must go for the full option because it is the easiest, safest and highest capacity but carries this one penalty. Clear as mud eh? :)

.4

.4

I think I understand what you are getting at. My concern is for traffic that has been established, THEN blunders. Not a frequent occurance I grant you, but on a clear day, we can often see who is flying on raw data down the approach. I suppose as long as 1 dot of LOC deviation does not trigger a blunder, then we'll be OK. I can't remember if use of the autopilot/flight director is mandated or advised when using this procedure.

HD

You are right I don't have the knowledge and I never meant to get drawn in to a discussion about TEAMing. I was using it to illustrate that I can no longer in good conscience use Heathrow as an example of all the best ATC practices combined and how the new proposal simply confirms this.

I could also have used the runway crossing/line up phraseology as as example. The constant stream of clearances, including the traffic to be followed plus the entry point to the runway for all departures means that it is no longer obvious when someone is lining up from an intersection because their clearance sounds the same as everyone else's. Hardly a major issue, but it does show that SA has been reduced by the procedure adopted, and thus Heathrow can no longer be used as an example of where the phraseology used is excellent.

It is important to point out that it is not the ATCOs fault. They are doing a great job. It is the procedures that are less than perfect, and I don't understand the reluctance to change them or consider alternatives.

G W-H

GWH,

Most, if not all, of us would agree with you about the relatively new phraseology for line-ups.

The fact we are now restricted to one conditional (also needing more marshalling at the hold), added to the longer R/T transmission which has to include the entry point means that R/T loading on Air Deps has increased, and we've lost a lot of our ability to manage that R/T time.

As you say we've also lost the added SA of only mentioning entry point for intersection departures.:ugh:

GWH

Thanks. In my 26 years in ATC I don't recall ever seeing traffic that has become satisfactorily established subsequently deviate from the localiser course to the extent that it would infringe the "No Transgression Zone" (2000ft wide, in between the approaches.) I have seen many fail to satisfactorily establish though.

I think autopilot/flight director may be mandated because we are going to need to operate parallel and without vertical separation for at least 5nm outside the current ICAO limitations. These require that 1000' vertical is maintained down to 10nm from touch down, which basically means using 2000' and 3000' as joining altitudes - not an option for Heathrow. Airspace limitations around Heathrow means that vertical will have to be thrown away at 15nm minimum. What is not yet know is the technical implication of that - the localiser beam is obviously wider that far out. The quesiton is can we guarantee sufficient navigational accuracy until traffic reaches the 10nm point, from which curent ICAO standards can be met.

The UK CAA seem very reluctant indeed to move on any of this stuff without unending studies and proof. If they can't be moved on this then mixed-mode is dead in the water, as would be alternation if runway 3 is built. The only realistic operating option in a 3 runway Heathrow would be (from the north) Mixed-mode, Departures, Arrivals.

.4

Now a 3 runway Heathrow operation operating as you suggest is something I could really get behind. I do realise that there will be a lot of understandable local opposition, but to my mind it is the safest (and at the risk of sounding cheesy) most orderly solution. Politically difficult I grant you, but safety costs and the cost is not always in purely monetary terms.

But what do I know!

G W-H