Originally Posted by
notam232
What was the ATC's plan for calling a go around if necessary? Look at his radar screen and hope that the departure becomes airborne before the arrival is over the threshold, otherwise call a go around? Wait until the arrival is 0.5 miles from the threshold and query the departure for their position on the runway? There needs to be a viable Plan B if the original plan doesn't work...
I don’t think the LC’s plan included a plan B. In another profession, we called this a “success-oriented plan.” I assume the LC’s mindset went something like this: I’ve got FDX at 3 miles and SWA is ready. I can meet my 2 mi increasing to 3 mi rule as long as I get SWA rolling in the next 30 seconds. How hard can that be? SWA should show up on my radar repeater within the next minute and life is good.
Note that in this plan, the LC has no way of establishing when SWA commences its takeoff roll. Then consider the following note from 7110.65, 5-8-4 (the 2 increasing to 3 rule):
NOTE−
1. This procedure permits a departing aircraft to be released so long as an arriving aircraft is no closer than 2 miles from the runway at the time. This separation is determined at the time the departing aircraft commences takeoff roll.
2. Consider the effect surface conditions, such as ice, snow, and other precipitation, may have on known aircraft performance characteristics, and the influence these conditions may have on the pilot’s ability to commence takeoff roll in a timely manner.