You can see the weather plain as day. But it’s miles away, right? How could that cause flight delays? Or worse, on a day that’s clear at the airport–yet your flight shows a one hour or longer departure day. Why?
Think big–or at least think far: miles translate into minutes in the air, and unlike your car on the freeway, we’re not creeping along under the storm–we have to get through it. At altitude, sure, we can go around weather or sometimes, even over a storm. But there’s the problem on take-off and landing: we are too low to do either.
First, let’s look at departure:
Sure, the weather is nearly twenty miles away. But in flight time, we’re talking about maybe three minutes. Then what?
Normally, there are at least six eastbound routes available, but as you can see, due to the weather that extends from the north to the south, even twenty miles away, there are only two routes available to go east: straight north, or straight south. And guess what? They’re the same ones that will have to be used for the inbound aircraft–and they’re already in the air, many for over three hours inbound from the east coast, or up to nine hours from Europe. Guess who rightfully has priority on the clear routes?
Here’s more bad news for your outbound schedule:
All of the departures–like the one pictured in above, and depicted on the navigation display with the radar image above–have very specific instructions for headings, altitudes and even speeds. But with the weather blanketing the area, no jet can comply with these very orderly instructions, so instead, air traffic controllers have to issue all headings and altitudes individually to each aircraft, checking to be sure that weather doesn’t interfere.
So the Air Traffic Control system must space jets by ten, sometimes ever twenty miles in trail to allow for the individual handling required, which means that instead of the usual interval of thirty seconds to a minute between launches, now takeoff will have to be 2-3 minutes in between. You’re number ten for take-off? Count on at least 30 minutes, maybe more–especially if the weather arrives over the field while you wait.
So, rather than have a traffic jam at the end of the runway waiting to take off, ATC issues all aircraft an “EDCT” (Expect Departure Clearance Time), or “edict,” as the acronym is typically mangled by crews, or even “wheels up time” in more common usage. This can usually mean an Air Traffic Control imposed delay on your pushback from the gate of forty-five minutes to an hour or more.
That presents another problem: while a delayed flight is held on the gate, the next aircraft scheduled for that gate will be delayed as well, either in the deplaning of passengers or the boarding of its next segment. At a major hub for any airline, there aren’t enough extra gates to make up for flights that must be held on their departure gates. If you arrive at the terminal and notice about double the normal amount of passengers milling about–that’s why: their outbound jet is waiting while a delayed flight sits on the gate, waiting for its EDCT time to roll around.
That’s what happens on the ground–here’s what happens in flight–which actually contributes to the confusion and delays on the ground.
See the racetrack pattern near “CAPTI?” That’s where we’re going to be holding, hoping the weather clears within our allotted holding fuel, which is about 45 minutes. The airport is under the blob of storms at the convergence of all the lines.
The jet we’re flying is being ardently awaited at DFW by 160 passengers who plan to fly on it to LAX after we deplane our Dulles passengers at DFW. But, we’re now on our way–diverting–to New Orleans because DFW is still closed and won’t open for at least an hour.
Add to that the fact that my copilot and I started our flight day at 12:35pm. We leave New Orleans at 11pm, but have to fly all the way to Abilene before we can turn back to the east around the scythe of thunderstorms bisecting Texas. What’s normally a one hour and ten minute flight turns into two and a half hours, pushing my first officer to a 14 hour flight duty day, landing at 2:15am.
Not sure what happened to all the LAX-bound folks, whether they got a crew to fly the leg or not, or what happened to the connecting passengers on our flight arriving after 2am.
All I know is that this promises to once again be another season of crowded skies, summer storms, bone-achingly long flight days and above all, a challenge to everyone’s fortitude and patience. Now that you know the “what and why” of the weather story–maybe you could explain it to the guy seated next to you, wondering why everything is so messed up because of a little old storm?