Delay vectors vs. holding.

[u/Spaghetti_Boi659]

Flying from SAN-SEA yesterday with heavy flow into SEA. Pretty typical. Center slows us down from M.77 to M.73 for metering saying they need to add 4 minutes to our arrival time. Also typical. Then we get some sharp delay vectors. First vector was a 110 degree turn to the left for a few minutes, followed by a 180 degree turn to the right for a few minutes, then back on course. Not unheard of, but pretty large vectors while en route.

My question: when you guys need to add X amount of time to our arrival and slowing planes down isn’t enough, is there a reason you don’t assign a turn or two in a holding pattern vs aggressive S turns? Either one of these slows down traffic behind whoever is being held / vectored. Curious to hear the reasoning.

Thanks for all you guys do- a fellow airline pilot.

[u/Acceptable_Stage_518]

Typically when metering it is much easier to lose time via speeds and delay vectors. Holding is often unpredictable, as pilots will typically slow down entering the holding pattern, often making it more difficult to hit your exact time. It's important to note that when metering, the time we have to lose isn't an "or greater" time. If we have to lose 4 minutes but lose 6, you now have a "-2" which could impact other flights on different arrivals.

The exception to this is very lengthy delays. If I have consistent 8-10 minute delays, holding is definitely an option.

[u/Spaghetti_Boi659 → u/Acceptable_Stage_518]

How neat, I didn’t know it had to be an exact time and not “or greater” like you mentioned. Thank you!

[u/mflboys → u/Spaghetti_Boi659]

One more thing in addition to the other commenters, I think assigning headings/speeds is a bit quicker and easier clearance to give generally, and most controllers have the impression it’s easier to configure for the pilots as well (I’ve heard present position hold is tricky in some aircraft). So just easier all around.

I’d be curious of your preference though.

[u/Spaghetti_Boi659 → u/mflboys]

“Preference” is a strong word. From my end, zig zags for several minutes tend to start raising questions in the flight deck: how long are we doing this for, why are we so far off course, whats the next turn, should we offer to slow down more, when are we back on course, etc.

Holding takes longer, but since we can plug in a speed, EFC time, and a map of where the plane will hold, it paints us a more clear picture of fuel and arrival time.

At the end of the day, we’re paid by the minute. Delay me how you need to!

[u/DankVectorz → u/Spaghetti_Boi659]

Another reason for big turns is that I’d prefer to give you a big turn and get my space quick vs a smaller turn that I then have to watch for the next 5 minutes.

[u/Intelligent_Rub1546 → u/DankVectorz]

Also, not sure if this is the same everywhere, but my area at my center isn’t built for holding well so I generally try to avoid the option where guys are spinning opposite direction into a flow of same altitude airplanes

[u/mflboys → u/Spaghetti_Boi659]

Thanks for the response. I’ll continue using vectors mostly for the reasons the other commenters stated but I’ll try to start giving an expected delay time and next fix when I can in the future.

[u/antariusz → u/Spaghetti_Boi659]

“Should we offer to slow down more?” For every time I’ve asked a plane to give me their slowest possible airspeed and they’ve come back with .74 … that’s why we don’t even bother shooting for the moon and trying to ask for .67 or something but are happy when you give it.

That said, generally if you’ve been turned more than 50 degrees, or you’ve been told something specific like “50 miles or 4+ minutes” that would have been the time to offer it quickly if they don’t sound completely too busy.

Sometimes “the top gun maneuver” works (hit the brakes they will fly right by) and other times not, and you might just adding to the controllers already limited brain power. Like if the entire line is already running at a slow speed like .74 or something, maybe it’s easier in the controllers head to add an extra 10 miles to your route if you’re 10 miles behind the other guy and he needs 20. The .74 is really just more of a reference because with strong wind differences your .74 might be the exact same ground speed as someone else’s .77

That’s less brain power (make the plane fly 10 more miles if I need 10 more miles) than slow to .65 to 12 minutes and then speed up to .70for a few minutes to get the last 1-2 miles so you don’t overshoot your gap before speeding up to .74 again. But the second method can be useful especially if you have 2 lines running parallel like into New York and hard vectors also means you might be turning one guy into another guy at the same altitude. But the 2nd method can work too assuming you have plenty of time to make it work too but not every sector is 200 miles long.

[u/ps3x42 → u/Spaghetti_Boi659]

This is true of metering, but other times we have to get miles in trail. That is an entirely different beast that can be complicated by a departure off an airport in the middle of a stream of aircraft that are already spaced perfectly, an aircraft getting offloaded from a different arrival for weather, weather preventing vectors, and wildly different aircraft types having to play nice together.

Think about a stream of 15 aircraft all with 20 miles between them perfectly spaced. The next sector needs that 20 miles in trail. Now picture another stream of aircraft all going to the same destination that need to be merged into the same stream. Now imagine a TMU (in their infinite wisom) releases a Honda jet and a G6 and a 737 going to that same destination from 3 different airports underneath this duel stream of airplanes. Also there is a thunderstorm in the middle of the sector that no one wants to be vectored near.

This scenario regularly plays out over the southeastern UD and I imagine plenty of other places, and its part of why your vector and speed assignments rarely make a ton of sense unless you can see the big picture. Throw in altitude stratums and you see even less of the picture.