handspring088

Hi!
I just flew BA 178- JFK-LHR this week. As we landed, it occurred to me that I can't recall every entering a holding pattern in Heathrow on a 747. Is it just that the TATL flights I take don't arrive in the time of crowed airspace, or is it the the 747s never do a holding pattern at Heathrow.? Just wondering.....

Skyrocker

it's pure luck, sometimes the traffic calms down for few minutes which mean planes are vectored directly to land, can happen at anytime during the day (unlikely during peak hours). The last time I landed in Heathrow without holding over London was 4years ago on the 10pm Lufthansa flight from Munich.

Flyingturkey

My years of engineering aren't sufficient to work this one out but perhaps someone else has.

Do the holding patterns surrounding London increase pollution to an extent wherein it would actually be more environmental to have a 3rd runway, assuming no additional flights?

Acid

I have almost always had some holding pattern on early morning arrivals at LHR coming from JFK or India regardless of airline/aircraft

catandmouse

I've had a couple of flights from GVA-LHR where we've gone straight to final, making the final turn somewhere around the Thames barrier or over LCY. It doesn't happen very often. The most direct approach, which has happened only once in my memory, we went straight to final really very close to LHR. I seemed to remember seeing Twickenham from 2 sides, but honestly that strikes me as being very close to touchdown to be feasible. I guess it was probably a couple of miles downstream (Chiswick?).

florens

I must have been really lucky, since I rarely encountered a holding pattern into LHR, but often merely an orbit (360° turn) and then into the arrival transition. The only holding patterns I remember were once during IRROPS and one during the runway switch at 15h00.

rossmacd

I will admit that the length of holding has reduced, particularly due to smarter ATC techniques that do not allow (particularly SH) flights to depart to reduce holding above London. But, the number of times there is a hold I do not believe has reduced. Thankfully gone are the days that holding for 1+hr (in my experience) but it doesn't mean the holding has been eradicated.

I even had a hold at ZRH two weeks ago - I was not impressed since I missed the train I wanted to be on and had to wait 10 mins on platform 3/4

KARFA

You must by flying in to a different Heathrow than everyone else

florens

I admit that I only had 35 flights into LHR over the last couple of years, so this might indeed be luck!

Was this during a runway change?

Waterhorse

For several years now traffic is speed controlled as it exits transatlantic airspace, and over the continent to give it an arrival time at the holding point. This "linear holding" is more efficient and less polluting than a traditional holding pattern. It reduces the holding time in the traditional holding pattern, though at busy times these still get used and it is not unusual for an aircraft to have to take a quick spin round to fit in with the other traffic. The amount of traditional holding has noticeably decreased as a result. I'm sure one of the ATC contributors could flesh that out more.

corporate-wage-slave

That, surely, is a holding pattern, albeit a short one, probably only 5 minutes.

Holding patterns do seem to have improved in the last year or so. A 30 or 45 minutes hold, so 6 or more times around the loop, aren't so common these days, and they used to be a near fact of life. Usually it's 1 to 3 times around. I've had quite a number of direct flights into LHR of late, including NCLs with gate to gate times with under an hour. For example BA1333 yesterday took off at 15:27 and landed at 16:21, which meant the aircraft arrived 20 minutes early on a schedule that gives 80 minutes for the 250 mile trip. On 1 May it took only 50 minutes runway to runway.

Getting airborne from LHR within 20 minutes of pushback is more trying!

florens

Sorry, I always thought there was a difference between an orbit (either lefthand or righthand turns) and a holding pattern (at least there is one technically, since there is no entry for an orbit). I agree that an orbit is a form of a holding pattern (not in the strict sense though), but it is a different procedure, that's why I made the difference.

Flexible preferences

Very interesting ^ Straight-in coming home from Miami last month

dakaix

There is a difference, an orbit means a 360 degree continuous turn "on the spot", as opposed to a hold which is two 180 degree turns with 2 minutes level flight in between.

The exact length of the level flight component of a hold is dependent on the altitude and clean speed requirement of the aircraft. It's not unknown to have a 5 or even a 10 minute leg, if it's at a particularly high altitude or it's known the hold will be particularly lengthy (since you consume more fuel in a turn than level).

My ATC friends have long remarked that Heathrow is working at its best if there's always one aircraft in the holds/stack, since it gives the Intermediate controllers maximum flexibility with sequencing. This is how you perceive the orbit on arrival, you enter the stack (having been told it'll only be once around) and then shortly after are told to exit the hold on a heading (before you rolled out of the first turn), thereby completing the "orbit".

Swanhunter

Any production engineer will confirm that machines (which essentially what the runways at LHR are) work best when they have a steady flow of product to process. That normally requires a buffer hence the need to have a small stack in inbounds.