Originally Posted by
UnableATC
Scenario one is easily avoided by not using conditional clearances relating to the runway.
Accepted, but if you like, we can modify the scenario a bit to say the landing aircraft has past the holding point, still on its landing roll when the departing aircraft is cleared to line up and wait. I take it from the second part of your response that in this case, the departing strip will be below the arrival (landed) strip...
In my location, I'm working combined procedural approach and Tower/Ground. The airspace isn't particularly big, only 31NM and up to 5500ft. In our runway bay in scenario one the departure will be below the arrival. Scenario two, the mid length above the full length. The reasoning behind this method is that it maintains the mechanics that are used in the active (airborne) bay with departures moving from the ground, up through the bay to get to the sky at the top and the arrivals are moving down through the bay to get to the ground. Scenario one, by having the departure below the arrival, it places a strip between the departing strip and the sky, blocking its progress up. Scenario two, the mid length is at the top, because it's closer to the sky than the full length (the mid length strip blocks the the full length strip from moving up the board).
This method is in contrast to the alternative of having the 'next to use' the runway at the bottom. So a departure strip has to move
down the runway bay before it can go
up through the board.
What I'd eventually like to know, and is the reason for starting this thread, is how far back in history it was when there was only one method of doing it, and what was the catalyst for the split into two methods. Obviously both methods work fine, and they both have their logical reasoning behind them. Has the two methods just always been the way it is, or is the divergence in response to a change in situational awareness methodology, ie paper strips as primary information moving to screen based situational awareness with strips for record keeping moving to screen based with integrated EFS? Does it stem from locations running airspace/approach and tower combined?
From what I've seen over the years, it depends...overall, though, the principle that the strip that represents the obstructing aircraft is oriented so that it impedes the one it is obstructing
Indeed, it depends is right, but for some, the strip below is seen as the one obstructing, for others it's the strip above, and I'd like to know why...
On that note, does anyone know of particular ICAO docs or similar that provide guidance on the topic? I've been looking but haven't found the answers I'm after yet.
Thanks for the inputs so far
Kieran