Delay Vectors, or Hold?

[FlyChicaga]

This was brought up elsewhere on the internet about London-Heathrow, how often you will be given holds of 5-20 minutes inbound for arrival delays. This rather than provided vectors or constant speed adjustments. I was thinking about it tonight, and am surprised this isn't used more as a flow technique. It is not often that we are given holds, but in all honesty I'd say it might be more prefered. In a hold, you are normally provided a few things which are invaluable to a pilot:

- EFC time.
- Constant speed/fuel flow/flight pattern for fuel planning
- Position on one point to navigate yourself, rather than rely on vectors and traffic alerts

There are other benefits I'm sure. Plus, there are benefits from an ATC standpoint:

- "Set and forget." Leave the pilots to navigate, therefore focusing on approach vectoring
- You know a starting point to release an aircraft for approach, and the time it will take them to get there
- Pilots can inform ATC quicker and more accurate when fuel critical
- Less workload

It seems to me that inducing holds more often, and earlier, would be a much better technique to handle heavy arrival rates. I know that often times we can be given speed adjustments many miles out from the destination, heading changes, delay vectors. All these things will increase fuel burn and flight time, but you can't predict with great accuracy just how much fuel you'll burn in excess. So, we add on layers of contingency fuel, which can add up.

Thoughts? Particularly from our resident ATCers?

 

[GIVDrvr]

When I worked ATC it was at a major hub terminal and we had this debate on a regular basis. When the weather dropped the available arrival rwys went from 4 to 1 and the arrivals backed up fast. Many controllers felt that they were not doing their jobs if they did not have twenty a/c on vectors to a 30 mile final at 170 kts. Nobody likes to be in a hold or issue on but what I think got lost in the discussion is the concept of acceptance rate. Any airport has a particular acceptance rate for a given configuration and weather minimum. As long as the final is being ran effectively with no greater than required separation the acceptance rate is being met. Then it becomes a question of whether you want to spend your time in a hold in a clean configuration and most likely at higher more fuel efficient altitude or dirtied up on vector at 5000 and 170 kts. I think i'd rather stay in the hold and get turned on 5 from the marker. Other issues that contribute to this discussion include pilots aversion to holding, the fact that time spent on delay vectors is not recorded in arrival delay stats but holding time is, and the fact that it is not as easy from a controller standpoint to generate a precise mile-in-trail feed to final out of a holding stack as it is from an arrival stream on a STAR. Just some thoughts. Cheers

 

[Vector4fun]

GIVDrvr Hit many of the high points. A big factor in my airspace is that there just really isn't "room" to hold many jets. Skyhawks and Cherokees down low isn't much problem, the holding airspace is small. Jets higher up at 250 kts though, that's a big chunk of airspace with 10 mile legs. It's really hard to find a spot to hold them that isn't in the way of an DP or STAR, or overflights. Centers may have some places where they can "park" a few jets, but then you wind up with irregular gaps in the arrival streams as you take folks out of the hold and feed them to finals.

This has really become a problem during convective WX. Half my airspace is occupied by lvl 3-4-5 echos, and the other half has aircraft deviating. Then one fellow wants to hold at 80-100 for a while to let a cell move past the airport. If traffic is light, we can do this for 5-10 minutes perhaps. Any longer, and it's almost guaranteed the guy holding is going to be seriously in the way. Departures in such conditions don't want to level at 70 for 20 miles to clear the hold, they naturally want to climb NOW and top as much of the WX as they can. I've had to tell folks that if they want to hold for 20 minutes, they are going to have to go back to Center and let them find a less busy area to do it in.

 

[Lead Sled]

Vector4fun...
Isn't that what TCAS is for?

'Sled

 

[paulsalem]

As far as generating spacing goes...what about a timed approach from a hold. Does anyone ever use those?

 

[jobear]

MSP center is usally pretty good about asking if you would rather slow or hold. Me I can slow as much as need be, altitude depending, and you don't have to explan to the Pax why your cirlcing over eau claire at 0715 AM and if they want a few spacing turns too as long as they aren't of the 90 degree variety. That and I can't dig out my holding pattern computer fast enough (wink wink).

What's an FMS?
Jobear

 

[Traveller Pilot]

In a hold you know EXACTLY where you are at all times..makes CFIT less likely..and CFIT is the number one killer in transport aircraft...

 

[DoinTime]

In a hold you know EXACTLY where you are at all times..makes CFIT less likely..and CFIT is the number one killer in transport aircraft...

Even in the Midwest?

 

[PaulThomas]

What's an FMS?
Jobear

Flight management system

 

[Traveller Pilot]

CFIT can happen to both the "horizontally, and vertically" disoriented pilots...least the hold minimizes the horizontal side of things...but I get your point....very few if any pilots fly, or descend into terrain without "knowing exactly where they were"...