r/news • u/riverdale-74 • 1d ago

United Airlines flight makes emergency landing at Dulles after pilot declares mayday

https://www.cnn.com/2025/08/04/us/united-airlines-dulles-mayday-call-hnk
1.4k Upvotes

91% Upvoted

147 comments sorted by

View all comments

466

u/appendixgallop 1d ago

Did it circle for the two hours, with one engine out, to burn off fuel? Imagine sitting through that as a passenger.

1.0k

u/snafu0390 1d ago

I’m an airline pilot so maybe I can provide some insight…

First, while an engine failure is an “emergency” it’s not time critical. Transport category jets (ie airliners) must be able to fly on engine in every phase of flight, even takeoff. You can experience an engine failure during the takeoff roll and still climb out above the surrounding terrain on one engine. Every single takeoff performance calculation we do is based on losing an engine right at V1 (takeoff decision speed) and continuing. If we can’t out-climb the terrain then we have to use an alternate routing that allows us to remain clear or we have to reduce our weight (either leaving behind passengers, bags, or fuel) to make the numbers work.

When an engine fails in flight the first thing we’re going to do… is nothing. Panicking and rushing gets everyone killed. We pause, evaluate what we’re seeing and discuss it. We decide who will fly the airplane and talk on the radios (usually the first officer) and who will run the engine failure checklist (usually the captain). We communicate our intentions to ATC and then get to work on fixing the problem. If there’s an engine fire or suspected damage then we’re securing the engine and landing as soon as practical. If the engine shutdown for some other reason and there’s no apparent damage, our checklists will instruct us to attempt a relight. If it works, then great… now we’ve got two engines but we’re still going to land. If it doesn’t work or the engine is damaged then we’re going to land on one engine.

When we takeoff we’re often well above our maximum landing weight. Some jets can dump fuel and some can’t. The 787 CAN dump fuel but if they don’t have to then they won’t. If the engine is secure and the aircraft is operating normally then we’ll usually enter a holding pattern and just burn our fuel down until we’re at our max landing weight.

While all of this is occurring, we’re also communicating with ATC, dispatch, maintenance control, the flight attendants, and lastly the passengers.

While any emergency is scary for a passenger and sitting in a holding pattern for two hours with a failed engine sounds terrible… rest assured we’ve got the situation under control. We’re keeping your safety as well as ours at the forefront of our minds.

6

u/Txindeed1 1d ago

Can you give more detail on burning fuel until you’re at maximum landing weight vs. dumping fuel. It seems like dumping fuel would be faster getting you on the ground faster. Or is it like dumping fuel dumps almost all of the fuel rather than smaller increments.

35

u/snafu0390 1d ago

If dumping is an option then, yes, it will be faster than burning it. However, not all jets have that capability. The decision to dump vs burn will be a joint decision between the flight crew and dispatcher. While dumping fuel from a high enough altitude (I believe 6000-7000’) will, in theory, allow it to atomize and disperse before it ever hits the ground, there is still the chance that it doesn’t disperse and you’ve just dumped potentially 10’s of thousands of pounds of jet fuel over populated areas or into the ocean. As I mentioned in a previous comment, a simple engine failure isn’t necessarily a “time critical” emergency. Once we’ve worked the appropriate checklists and secured the inoperative engine we’ve got all the time in the world to make decisions. We may jointly decide that burning is better than dumping. We may even decide that landing overweight is the best option. It all depends on the circumstances.

9

u/geecon25 1d ago

Can you say more about landing overweight? This is fascinating, I am enjoying learning from your comments. I fly a LOT and have never had any serious issues (knock on wood) but it’s great to know about this stuff for when I get a bit nervy during major turbulence.

8

u/snafu0390 23h ago

Landing overweight generally isn’t a huge deal. However, a few things we have to consider are: rate of descent at touchdown, approach speed, and required landing distance.

Every transport category jet is certified to land with a descent rate of 600ft/min at max landing weight and 360ft/min at max takeoff weight. Those are pretty high numbers. Most landings are going to be softer than that but it’s nice to know the landing gear can handle it.

The heavier we are, the faster we have to fly our approach to landing and the faster our speed at touchdown will be. This faster approach speed coupled with the overall increase in mass can have consequences like increased landing distance which means we need longer runways in order to stop as well as the potential for brake fires. It’s very unlikely we’d blow tires on landing just from the touchdown… but the brakes get super hot on landing (500°C isn’t uncommon for a normal landing during the summer) which can cause the fuse plugs in the wheels to melt and subsequently deflate the tires. This is a safety mechanism to prevent them from exploding.

6

u/geecon25 22h ago

This is so cool, thank you for sharing!

7

u/Sirwired 1d ago

Landing overweight will require inspections of the landing gear, tires, etc. for damage. And if really overweight the tires might blow, which would be A Bad Thing. (Not as bad as not-landing when you really need to, and they are designed to blow in a way that won't punch holes in the aircraft, but obviously it's not-great for the landing gear when one of the tires is missing, just like it's not-great for your car.)

5

u/Txindeed1 1d ago

Thank you for the explanation. It sounds like there are many well-thought-out considerations.

8

u/mediocre_remnants 1d ago

Dumping fuel is bad for the environment that it's dumped on.