The Hidden Complications of Flight Delays
Running an airline is a complicated orchestra of moving parts when everything's on schedule. Throw in delays, and the complexity multiplies fast. Let's look at some of the less obvious problems delays create.
Crew Duty
We want healthy, well-rested pilots flying our airplanes. Fatigue and flying don't mix. The FAA sets duty limits for pilots, and those rules changed a few years back. What used to be a complicated set of regulations got replaced by an even more complicated one. The biggest change is how a delay affects those duty limits.
Under the old rules, as long as the flight left the gate with enough time to legally finish under the duty limit, a delay was just part of the job. Say a pilot had three hours of duty left. Push back for a two-hour-thirty-minute flight and you were fine, even with an hour of delay on the taxiway that technically put you over your duty day. The flight could still go, at the pilots' discretion.
Now the takeoff itself has to happen within the duty limit, not just the gate departure. That gives pilots a hard line: get airborne by a certain time, or head back to the gate and start a rest period. The result is less flexibility and pilots "timing out" a lot more often.
The Snowball Effect
Take a single flight with a mechanical delay. The impact is manageable. The airline needs to find replacement pilots, and that's a lot easier at a hub where crews are based. At a smaller, more isolated airport, it can be difficult or flat-out impossible.
Now compare that to bad weather or an air traffic control delay, which can hit dozens of flights at once. Suddenly the airline isn't looking for two replacement pilots, it needs ten or more, fast. Every delay finding those replacements adds more stress to an already strained operation.
Airport Capacity
In an earlier piece, "Nobody Likes Delays," I got into runway and approach capacity. Gate and ramp capacity matter just as much during weather delays. Every gate runs a tight schedule with barely any downtime between flights. When a plane sits at the gate past its scheduled departure, it creates a ripple effect. The next flight assigned to that gate either waits for it to clear out, or, if the delay drags on, moves to another gate if one's available. Airlines try to avoid that second option, since it means moving every outbound passenger and their bags to a new gate.
So say there's a plane on the ground that needs your gate. The airline's left with two options, and neither one is great. One is to send the outbound aircraft out empty and park it somewhere on the ramp temporarily, which just means repositioning it back to the gate later to actually load passengers. The other is to load everyone up, push back, and hold at a remote spot until the assigned takeoff time. That keeps the plane and passengers close to the runway and ready to go. It also creates a different problem.
Flight Time
Remember those crew duty rules? Pilots have limits on both duty time and flight time, and they're not the same thing. Duty time starts the moment a pilot shows up at the airport and runs until they leave at the end of the day. It includes time in the air, flight planning, and even breaks between flights.
Flight time, by the FAA's definition, starts the moment the aircraft begins moving for the purpose of flight, which in practice usually means pushback, and ends when it parks at the gate after landing. Taxi time counts too, even sitting with the engines shut down. So when a flight pushes back and then sits waiting to get airborne, every minute of that delay eats into the pilots' allowed flight time for the day. Unplanned flight time is never something an airline wants to add.
The Tarmac Delay Rule
The DOT enforces what's commonly called the tarmac delay rule. It's a complicated regulation with a lot of moving parts, but the short version is that it applies to both departing and arriving flights, and airlines have to do everything possible to stay under the time limit. Weather, safety, and air traffic control all factor into whether a fine actually gets imposed. And the fines can be enormous. It's a good rule overall, but it adds another layer to an already messy situation.
Here's an example. We're flying Atlanta to New York, and thunderstorms shut down departures out of Atlanta. We push back and then sit with the engines off on the taxiway. After a long wait, we slowly creep up through the line of planes waiting to take off. Two and a half hours after leaving the gate, we're getting close to being number one for departure, but there's no guarantee we'll be airborne before the three-hour mark. So we return to the gate and let passengers off. We might have been thirty minutes from takeoff. Doesn't matter. The penalty for guessing wrong is too big to risk. And a return like that usually adds at least another hour to the delay.
All of this is, frankly, pretty complicated. As a passenger, there's no way to see all the moving pieces, and what we've covered here is only part of it. Hopefully this clears up a little of what's happening the next time you're stuck waiting on a delayed flight (or maybe it just adds to the confusion).
The Big Secret
One last thing. Before you take out your frustration on the crew, know that they're probably just as unhappy about the delay as you are. Pilots and flight attendants typically don't get paid until the plane pushes back from the gate. Sit at the gate for two hours, and the crew isn't earning a dime for it. Depending on how the delay plays out, it can even cut into their pay down the line by affecting what flights they're legal to work. Moments like these are a pretty good time to remember the golden rule.
original publication 2019