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Sequencing into LHR

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Sequencing into LHR

Old 13th Apr 2018, 06:57
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Sequencing into LHR

This morning at 06:00 I noticed on FR24 that all LHR arrivals were very well sequenced so that each airplane almost made a straight in approach, with no holding orbits. This spacing seemed to occur well before the Irish Sea, so not whilst in contact with LHR Tower. The inbound stream from the East was also well merged with those from the West.


So the question is... Do they have onboard telemetry which is linked to the LHR sequencing computer, which tells them when to slow down or speed up..?
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And I suppose the follow up question is... Could this telemetry ever be connected to the Autopilot...?
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Old 13th Apr 2018, 07:25
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This might be of interest: Air traffic control changes
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Old 13th Apr 2018, 07:48
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This reminds me of my time with ATC (technical support, not controlling!) in Saudi Arabia in the 70s & 80s. Inbound flights when arriving at Jeddah FIR were often told to be at a certain reporting point by a specific time. I always assumed this was to facilitate some form of order in the arrivals stream.
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Old 13th Apr 2018, 07:56
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Originally Posted by scifi View Post
spacing seemed to occur well before the Irish Sea, so not whilst in contact with LHR Tower
The sequencing function was removed from LHR Tower in October 1993.
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Old 13th Apr 2018, 08:47
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Aaaarh... Just looked at FR24 again, at 09:45, and all the LHR arrivals are now doing orbits before landing.... Well it was good whilst it lasted...
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Old 13th Apr 2018, 08:54
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Originally Posted by scifi View Post
Aaaarh... Just looked at FR24 again, at 09:45, and all the LHR arrivals are now doing orbits before landing.... Well it was good whilst it lasted....
A simple comparison of the number of arrivals at this time of day compared to the number at 6am should answer your question, particularly as the earlier ones are being more evenly spaced at the moment, as per my link.
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Old 13th Apr 2018, 09:17
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Thanks for the link, it is very informative...
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Old 13th Apr 2018, 09:33
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scifi.. I am sure that my buddy Talkdownman and I could write ten pages on Heathrow sequencing but, basically, it's all decided by the controllers. Over the years there have been a number of attempts to "computerise" the task but none has been as efficient as brainboxes of highly trained humans. As TDM mentioned, the approach function was moved from the Tower building at Heathrow to West Drayton many years ago and subsequently moved to Swanwick. "Heathrow Tower" is the control room at the top of the tower which controls traffic on the ground and arriving flights from about 10 miles out. Outbounds are transferred to London Control as soon as they are airborne.

Details of all arriving flights appear on CCTV and the landing order is initially sorted to take account of wake turbulence categories to achieve the best landing order and to calculate expected approach times when aircraft are holding. In the end it is the Heathrow Directors who decide the actual landing order.

HTH
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Old 13th Apr 2018, 12:09
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Thanks HD for the reply. So the Directors juggle the speeds and altitudes to maintain a sequence, then convey that information by voice RTF to the aircraft. What I am wondering is, is there a telemetry link, such as ACARS, that keeps the aircrews informed of the required airspeeds and altitudes... ( Much the same as in Formula 1, where drivers have a 'Delta' to follow so they are on schedule for a fast lap.)


I was thinking that any information sent by telemetry, would reduce the amount of voice transmissions required. However I realise this could create a clash, if the telemetry said one thing and the Director said another.
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Old 13th Apr 2018, 12:31
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Perhaps we could tell the aircraft behind to 'lock-on' to the aircraft in front and follow it by one minute and forty three seconds or something, and tell the pilot to put his paper down, stub his fag out, and call ground on 121.9 after it lands itself.
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Old 13th Apr 2018, 13:13
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Originally Posted by Talkdownman View Post
Perhaps we could tell the aircraft behind to 'lock-on' to the aircraft in front and follow it by one minute and forty three seconds or something, and tell the pilot to put his paper down, stub his fag out, and call ground on 121.9 after it lands itself.
Ah, the joys of radar trail.....(for departures I hasten to add)...
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Old 13th Apr 2018, 15:03
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Scifi wrote: Thanks HD for the reply. So the Directors juggle the speeds and altitudes to maintain a sequence, then convey that information by voice RTF to the aircraft.

No, there is no telemetry link for this particular task. Aircraft are under continuous radar control in busy airspace so the controllers and pilots are talking to each other all the time. ATC controls altitude, heading and speed.
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Old 14th Apr 2018, 23:36
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It would have been pure fortune that nothing held in the internal holds if that is exactly what happened however there is XMAN now in place where by the Area ATC sectors and a few adjacent FIRS can see the delay for each aircraft, if it is above 5 minutes we slow them down. Simple method to reduce some holding.
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Old 21st Apr 2018, 17:04
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Sorry to interject here but with time based separation (TBS), is the sequence 'suggested' or is it purely up to controller input? Also, is there any interface with the new electronic strips for ensuring the correct separation based on the sequence, is used for the display of the TBS radar markers?
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Old 28th Apr 2018, 21:04
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Originally Posted by HEATHROW DIRECTOR View Post
Scifi wrote: Thanks HD for the reply. So the Directors juggle the speeds and altitudes to maintain a sequence, then convey that information by voice RTF to the aircraft.

No, there is no telemetry link for this particular task. Aircraft are under continuous radar control in busy airspace so the controllers and pilots are talking to each other all the time. ATC controls altitude, heading and speed.
Actually the handling pilot controls heading, altitude and speed, ATC request, or instruct what they need. And as a pilot an early morning arrival, or an arrival with duty limits approaching behind an aircraft who canít follow the controllerís wishes can raise the blood pressure to levels the CAA medical department canít imagine!

I took TDM flying (in a helicopter back in 2005) and well remember discussing frustration with him in a bar afterwards.

SND
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Old 29th Apr 2018, 11:48
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Originally Posted by Sir Niall Dementia View Post


I took TDM flying (in a helicopter back in 2005)

SND
********* 26??
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Old 1st May 2018, 07:14
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Originally Posted by Talkdownman View Post
********* 26??
Indeed! Bonjour Matelot!

SND
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Old 13th Jan 2019, 15:24
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Originally Posted by Mister Geezer View Post
Sorry to interject here but with time based separation (TBS), is the sequence 'suggested' or is it purely up to controller input? Also, is there any interface with the new electronic strips for ensuring the correct separation based on the sequence, is used for the display of the TBS radar markers?
There exists a Schedule Activated Management System (SAMS) which optimizes aircraft arrivals streams at congested airports. This is also patented technology under Patent Nos: US 6584400 B2 & US 20020177943 A1.
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