View Full Version : EGLL sid
bio161
4th May 2013, 11:52
Hi everyone,
:O
Can anyone of you explain me something i noticed just today.
Flying out of EGLL i noticed that ALL the departures of LHR are "still" conventional departures, not even RNAV overlays.
It made me thinking that as soon as one nav aid goes down they have to provide radar guided sid (even if this is actually standard in LHR :suspect: )
Is this choice to have conventional departures a choice rather than a need? Is there any background info?
Thanks to you all,
Bio161 :ok:
Capt Fathom
4th May 2013, 11:58
How often do the nav aids go down?
bio161
4th May 2013, 12:17
now this is a positive answer! :ok:
maybe never, maybe once every 10 years, maybe everyday..the question is just background related Capt Fathom..is there ANY reason behind the fact they operate only with conventional sid?
i admit, it can be as easy as it works quite good and they do not need anything else. i´m only wondering if any of you have some kind of other sources to explain it...seriuosly hopefully...... :hmm:
MU3001A
4th May 2013, 12:32
Newtons 1st law would be my bet.
Fullblast
4th May 2013, 20:19
Good point actually, don't have the right answer, but can tell what happened to me four years ago in Gatwick (ok, it's not the same but pretty close :} ); on the approach, just upon ILS intercept, with the app mode armed and vor/loc and g/s captured with a/p on we both noticed the airplane symbol on the map display going far away from the magenta line...asked tower about ILS status, the controller wait a bit before answer than he replied "sorry, ILS on test (or something like that and no notam) and not working, can you accept radar approach?", we were in the cloud so we couldn't see anything, accepted radar approach and fortunately break out at 800 feet and land...so, Fathom, don't know how often that happens, but for sure it happens, so you'd better be prepared.
FB
Tay Cough
4th May 2013, 20:53
Is this choice to have conventional departures a choice rather than a need? Is there any background info?
Due mainly to the fact that NATS and the CAA remain in the dark ages. The airlines are lobbying for change for a number of reasons.
Akrapovic
5th May 2013, 10:04
Cuts down on briefings . . .
aterpster
5th May 2013, 13:47
bio161:
Flying out of EGLL i noticed that ALL the departures of LHR are "still" conventional departures, not even RNAV overlays.
It made me thinking that as soon as one nav aid goes down they have to provide radar guided sid (even if this is actually standard in LHR http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/cwm13.gif )
What kind of FMS are you using? Must be a very basic model. In modern FMSes all ground-based navaid SIDS (and STARs) are coded to be flown with LNAV. Here is an "entry level" light airplane Garmin G-1000:
http://i201.photobucket.com/albums/aa214/aterpster/EGLLSIDs_zps6c18116f.jpg
Aterpster - I think the poster means 'conventional' as in not using RNAV waypoints, but VOR Rad/D and NDB. He/she was not asking about LNAV. Have a look at a chart?
aterpster
5th May 2013, 17:24
BOAC:
Aterpster - I think the poster means 'conventional' as in not using RNAV waypoints, but VOR Rad/D and NDB. He/she was not asking about LNAV. Have a look at a chart?
Because he mentioned RNAV overlay, my point is all the ground-based SIDs are coded in today's LNAV systems as LNAV departures. As an example:
http://i201.photobucket.com/albums/aa214/aterpster/BUZAD9R_zps75c28883.jpg
http://i201.photobucket.com/albums/aa214/aterpster/BUZAD_zps8ed83921.jpg
bio161
8th May 2013, 10:22
Hallo aterpster,
Thank you all for your answers!
Maybe i´m wrong, but when i intend RNAV overlay i intend a conventional SID which is constructed with RNAV waypoints for the whole profile. When a SID is simply conventional it does have a Lateral navigation in the FMS, but these are all waypoints which are not RNAV (officialy i mean) being just based on a reconstruction of the SID from the FMS. So the SID itself is not certified to be flown managed from the FMS profile (altough all of us do it instead of following needles).
In the SID description when i have a SID which is RNAV overlay i have the description of BOTH paths. the one conventional and below the one according RNAV waypoints.
When i just have a conventional SID i just have the conventional description. And, at least for the LIDO charts, this is the case of LHR.
Thanks anyway! :ok:
It made me thinking that as soon as one nav aid goes down they have to provide radar guided sid - yes, I am sure you are correct, in particular the westerly NDBs. In reality, however...............................:)
It's not NATS or CAA, the airport operator owns the SIDs.
DaveReidUK
8th May 2013, 11:40
It's not NATS or CAA, the airport operator owns the SIDs.And of course the initial part of each SID corresponds to the NPRs, which have been more-or-less set in stone at LHR since the 1960s.
And for the OP, if a navaid required by a SID is out of service, it is NOTAMed and aircraft who cannot accept the SID are advised to inform ATC prior to start. In 15 years at LHR, I can count of the fingers of one hand how many times an aircraft has requested vectors due to this.
We did a recent survey of operators, and all of those questioned are flying RNAV overlays on top of the conventional navigation SIDs.
and all of those questioned are flying RNAV overlays on top of the conventional navigation SIDs. - I'm not sure where 'RNAV overlays' have got to since I quit flying, but it used to be a requirement to monitor track keeping using 'conventional' aids AND not to use the 'turn anticipation' built into RNAV ie where you route via an NDB the RNAV should take you OVER that beacon and not turn early for the new course. Thus in the BUZAD shown you would be required to pass over the D10 before turning onto the BIG 331 whereas the kit might 'anticipate' that turn. Folk like ATERPSTER or OBN will be able to update here - it may have changed. Certainly the last 733's I flew were NOT allowed to fly 'RNAV' SIDs or STARs and I recall always asking in ?Oslo? for vectors since they only had RNAV SIDs (and the vectors always reduced the mileage.:ok:)
BOAC - FMC updates along with better SID coding have pretty much sorted those problems.... (737...)
On the bus, with its overfly function then we can ensure that waypoints are overflown. However, with only a few exceptions, the coding is pretty much spot on in the first place.
HEATHROW DIRECTOR
8th May 2013, 17:40
BUR VOR went out one day. Imperial Airways VC-10 asked how he was supposed to fly the SID without the VOR. I said he should expect radar vectors. "No thank you; we'll use INS". Prat!
Thanks as always, Cough - are you saying you could now fly the Buzad with no LON V/D in 'RNAV' without GPS ie is DME/DME enough to make it legal?
DaveReidUK
8th May 2013, 19:29
Thus in the BUZAD shown you would be required to pass over the D10 before turning onto the BIG 331 whereas the kit might 'anticipate' that turn.If if helps (which it probably doesn't), here are the AIP and FMS versions of the BUZAD3K SID:
AIP:
Climb straight ahead to LON D1.5, then turn left onto track 052° to intercept LON VOR R073, cross LON D10 at or above RWY 09L 3000 and turn left onto BIG VOR R331, cross BIG D20 at or above 5000 and BIG D23 at 6000 to BUZAD.FMS:
SID BUZA3K RNW 09L FIX OVERFLY D113B AT OR ABOVE 590 TRK 052 INTERCEPT RADIAL 073 TO FIX D073J FIX OVERFLY D073J AT OR ABOVE 3000 TURN LEFT DIRECT FIX D331T AT OR ABOVE 5000 FIX D331W 6000 FIX BUZADI would interpret "OVERFLY D073J" (D073J corresponds to LON R073 D10) to mean that the turn won't start until after that point, but I could well be wrong.
Sorry BOAC - 5 years since I stepped from that seat - I wouldn't have the confidence to say either way! What would you think?
Cough
ps The FMS does have RNP vs ANP alerting...
The LTMA wil eventually be RNP1, P-RNAV airspace. There really isn't any need for RNAV overlays in the first place as the present SID's work very well and are mainly flown by RNP1 capable aircraft accurately tracking through modern Flight Management Systems.
There is as yet no mandate within Europe for RNP1 within TMA's. The problem arises in the cost of conversion etc for aircraft that aren't currently compliant. Whilst Heathrow users may be, that doesn't necessarilly hold true for the whole of users of the LTMA airspace.
There was a stakeholders meeting in Brussels in Feb of this year, and indications are there will be no mandate before circa 2020.
In the mean time, overlays could be used, but the current system works, indeed it works well, why spend money on what will only be an interim change but still requires the ground navaid infrastructure to be maintained for non compliant types/operators?
That said, NATS would love to move away from the current infrastructure - VOR's, NDB's etc are both expensive to maintain and of course require staff to carry out that function....
Hope the above helps..
30W