MLS at LHR
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MLS at LHR
Clearing out the car boot for first time in ages came across my old airband scanner (yes I know I shouldn't relaly use it ) and switching it on for a few minutes heard a couple of LHR bound flights read back instructions as turn left/right xxx for the 09R localiser then the microwave.
I looked this up on pprune and google and was surprised MLS was being used as alot of comment suggested it would not get mas take up due to GPS advanaces. Also where it was used like LHR the suggestions were it could allow a few landings on the departure runway at busy times (clearely not when i heard it as the a/c concerned were for 09L. Also opinion from LHR ATCO community on that thread seemed to be that curved approaches, another MLS feature,would not work at LHR and in any event why close the localiser first .
I am sure there are good reasons but it seemed odd to establish on the localiser and then use MLS since I imagine the rate of descent from the same point would be the same for both systems..I kno e the MLS is more accurate but I would not have thought that flying the approach fractionally more precisely made any difference in yesterdays conditions which while not nice were no where near CATIII
I had alonger listen later on and a few more a/c read back the same instruction -all BA too-any one else use it
PB
I looked this up on pprune and google and was surprised MLS was being used as alot of comment suggested it would not get mas take up due to GPS advanaces. Also where it was used like LHR the suggestions were it could allow a few landings on the departure runway at busy times (clearely not when i heard it as the a/c concerned were for 09L. Also opinion from LHR ATCO community on that thread seemed to be that curved approaches, another MLS feature,would not work at LHR and in any event why close the localiser first .
I am sure there are good reasons but it seemed odd to establish on the localiser and then use MLS since I imagine the rate of descent from the same point would be the same for both systems..I kno e the MLS is more accurate but I would not have thought that flying the approach fractionally more precisely made any difference in yesterdays conditions which while not nice were no where near CATIII
I had alonger listen later on and a few more a/c read back the same instruction -all BA too-any one else use it
PB
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Only in use for the short haul BA Airbus fleet. No one else. It was intended to reduce separation in LVPs. It mimics the ILS, so it is localiser then glide slope. It behaves in exactly the same way. Not much else to say really...
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PB,
Aircraft on an MLS approach use the MLS 'localiser', technically called the 'azimuth', not the ILS localiser.
The benefits are all realised in low visibility (600m vis); assuming a pair of landing aircraft with the follower on an MLS approach, the lead aircraft has to be 82m from the centreline of the runway to enable a landing clearance to be given to the follower. Compare this with 137m if the follower is on an ILS approach (150-192m if the lead is an A380).
However, it is true to say that the new wide apature array ILS localiser systems coming into use now have similar benefits.
Aircraft on an MLS approach use the MLS 'localiser', technically called the 'azimuth', not the ILS localiser.
The benefits are all realised in low visibility (600m vis); assuming a pair of landing aircraft with the follower on an MLS approach, the lead aircraft has to be 82m from the centreline of the runway to enable a landing clearance to be given to the follower. Compare this with 137m if the follower is on an ILS approach (150-192m if the lead is an A380).
However, it is true to say that the new wide apature array ILS localiser systems coming into use now have similar benefits.
Yes, all LHR runways have MLS as well as ILS.
Although the advantage of MLS is only realised during LVOs, BA and LHR ATC agreed some time ago that MLS-equipped aircraft should use MLS as the default landing aid in all conditions. Reasons include controller and pilot familiarity with r/t terminology, use and limitations of the equipment and practice in applying the reduced spacing required for following aircraft using MLS.
The intention is that MLS procedures and terminology become so 'normal' that during LVOs no difference from 'normal' is required.
Although the advantage of MLS is only realised during LVOs, BA and LHR ATC agreed some time ago that MLS-equipped aircraft should use MLS as the default landing aid in all conditions. Reasons include controller and pilot familiarity with r/t terminology, use and limitations of the equipment and practice in applying the reduced spacing required for following aircraft using MLS.
The intention is that MLS procedures and terminology become so 'normal' that during LVOs no difference from 'normal' is required.
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MLS (Mythical Landing System)
MLS, a system whose time has come,... and GONE. It is now an utter wast of time, energy, and money to invest in it any farther.
The industry having worked on MLS since the 40s, and personally having helped with the original USAF, FAA, and ICAO MLS efforts in the 60s and 70s, into the 80s, and having authored the original ICAO manual of All-Weather Ops with Derek Helmore (UK CAA) and a long list of other FAA authority criteria for AWO, I can confidently say that FAA did the right thing by finally killing MLS dead. Now that needs to happen in Europe too.
The future of NAV globally is in RNP and GBAS/GLS. Not MLS.
The industry having worked on MLS since the 40s, and personally having helped with the original USAF, FAA, and ICAO MLS efforts in the 60s and 70s, into the 80s, and having authored the original ICAO manual of All-Weather Ops with Derek Helmore (UK CAA) and a long list of other FAA authority criteria for AWO, I can confidently say that FAA did the right thing by finally killing MLS dead. Now that needs to happen in Europe too.
The future of NAV globally is in RNP and GBAS/GLS. Not MLS.
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....and there we all were thinking it was the future.
I'm not sure what 'investing' you think is going on in Europe, but MLS has been operational at LHR, and only LHR, for years, and a significant proportion of based aircraft are equipped. The 'investing' took place years ago, so why wouldn't we use it to gain benefit from it while we can?
It has also allowed the validation of many aspects of procedures that will equally apply to GBAS, such as optimised operations in LVP in terms of a landing clearance trigger line and mixing ILS and non-ILS traffic in LVP.
While I agree RNP/GBAS/SBAS is the future, I don't think use of MLS at one airport in Europe has been a major delaying factor here.
I'm not sure what 'investing' you think is going on in Europe, but MLS has been operational at LHR, and only LHR, for years, and a significant proportion of based aircraft are equipped. The 'investing' took place years ago, so why wouldn't we use it to gain benefit from it while we can?
It has also allowed the validation of many aspects of procedures that will equally apply to GBAS, such as optimised operations in LVP in terms of a landing clearance trigger line and mixing ILS and non-ILS traffic in LVP.
While I agree RNP/GBAS/SBAS is the future, I don't think use of MLS at one airport in Europe has been a major delaying factor here.
Last edited by Gonzo; 22nd Feb 2016 at 20:40.
