So I was just in PHL today, and watched what was going on in the evening rush. One thing I saw didn't make sense to me.
27L and R were the actives, and 27R was being used for all arrivals, while 27L was being used for all departures. It was a perfect VFR day. I'm trying to understand why both runways can't be used for both functions simultaneously.
Here's how I could envision something like this working:
Instead of arrivals being spaced along the glide path at minimum separation (I don't have MATS handy so I forget exactly how far apart they're supposed to be...three miles comes to mind), add an additional, say, 25%. Then departures could fit in this window between arrivals, with enough room to spare to handle the delay in getting the departing aircraft's takeoff roll started.
Now we've cut this one runway's landing capacity by to 75% of its original value. But there's a second runway where we can put more flights! If we implement the exact same strategy on the other, we now have 150% of the original landing capacity of the airport. I know simultaneous landings can be done on runways closer than PHL's during VFR conditions; SFO does it all the time.
The cool part is we've done exactly the same thing with takeoffs. Cut each runway to 75%, but the sum total is 150% of the original capacity.
So, can anyone explain why this hasn't been done?
27L and R were the actives, and 27R was being used for all arrivals, while 27L was being used for all departures. It was a perfect VFR day. I'm trying to understand why both runways can't be used for both functions simultaneously.
Here's how I could envision something like this working:
Instead of arrivals being spaced along the glide path at minimum separation (I don't have MATS handy so I forget exactly how far apart they're supposed to be...three miles comes to mind), add an additional, say, 25%. Then departures could fit in this window between arrivals, with enough room to spare to handle the delay in getting the departing aircraft's takeoff roll started.
Now we've cut this one runway's landing capacity by to 75% of its original value. But there's a second runway where we can put more flights! If we implement the exact same strategy on the other, we now have 150% of the original landing capacity of the airport. I know simultaneous landings can be done on runways closer than PHL's during VFR conditions; SFO does it all the time.
The cool part is we've done exactly the same thing with takeoffs. Cut each runway to 75%, but the sum total is 150% of the original capacity.
So, can anyone explain why this hasn't been done?
