SID Advice.

[max alt]

Can I ask you clever blokes for some advice on sid instructions from Lgw for example.Following the SID with step climbs,contacting london confirming passing alt climbing to alt and sid etc, I receive the call roger squawk ident climb alt 4000.{ the initial sid alt}Break break,the controller then goes into a very busy period.Can I climb above that alt in accordance with the sid,or should I wait untill I receive a specific climb instruction.What would you like me to do.?
My regards to the worlds best,
MAX ALT.

[TopBunk]

Max Alt

No,no,no. On the Aerad/Thales charts there is a comment to the effect 'DO NOT CLIMB ABOVE CLEARED ALTITUDE DUE TO INTERACTION WITH OTHER TRAFFIC'. This means do NOT climb above cleared altitude until cleared so to do by ATC.

[BOAC]

This thread (http://http://www.pprune.org/forums/showthread.php?s=&threadid=15101&highlight=sid) may also be of interest.

[av8boy]

"Interaction?" Yeah. Serious interaction. Joules and joules of interaction... ;)

Dave

[bookworm]

No,no,no. On the Aerad/Thales charts there is a comment to the effect 'DO NOT CLIMB ABOVE CLEARED ALTITUDE DUE TO INTERACTION WITH OTHER TRAFFIC'. This means do NOT climb above cleared altitude until cleared so to do by ATC.

That's not what it says in the AIP, and I suggest that you review the chart you've seen very carefully, because your instruction leads to a very different answer from what I read into the intention of the AIP.

"WARNING - STEPPED CLIMB
Due to interaction with other routes pilots must ensure strict compliance with the specified climb profile unless otherwise cleared by ATC."

That makes it even more important that MAX ALT's question is resolved. The note suggests that it's dangerous to be below the specified profile level. So if instructed to "climb to altitude 4000 ft", what do I do if it appears that I need to climb further to adhere to the profile?

[max alt]

Thanks for the replies.Top bunk if the published sid holds me to an initial block alt,that is my first level,fine.However the sid may have dme step alts initially alt 4000,15 dme xxx alt 5000.If you as the controller are so busy that my initial call is acknowledged but no further instuction is given to me and i pass the dme xxx point are you expecting me to climb or remain at the initial block altitude and wait for a call.
regards Max alt

[WMD]

max alt - the right turn outs off gatwick when on 26 will often be climbed to 5000' on first call - under the heathrow's - eventually the SIDs go to 6000 but I wouldn't expect you to climb above 5 until cleared because I've already taken you off the SID by going to 5000 in the first place.

However, in your scenario - the initial step climb is to 4 which you've reported climbing to and the controller has confirmed the same alt. As far as I can tell, you haven't been taken off the SID (Unless the controller said to maintain 4000 on reaching) and therfore should continue with the step climbs as published.

[bookworm]

However, in your scenario - the initial step climb is to 4 which you've reported climbing to and the controller has confirmed the same alt. As far as I can tell, you haven't been taken off the SID (Unless the controller said to maintain 4000 on reaching) and therfore should continue with the step climbs as published.

So what you're saying is that when the pilot hears the words "climb to altitude 4000 ft", he should look at the SID to work out if that's what he's expecting to do or not? If it's in accordance with the SID, he should continue with the step climbs. If it's not in accordance with the SIDs he should maintain 4000 ft until further cleared.

Sounds like a recipe for disaster to me. :ooh:

[Max Angle]

So if instructed to "climb to altitude 4000 ft", Well if I heard that instruction I would stop at 4000ft and remain there until re-cleared or I had checked with the controller that I was clear to climb with the SID. I would view the instruction as a re-clearance of the vertical portion of the SID.

[DFC]

In the situation described, I would maintain 4000ft on reaching unless terrain or controlled airspace dictated otherwise.

The controller is aware of the traffic and unknown to us, may have an aircraft that he is about to clear to 5000ft which would be a conflict if we did not do what he said until told otherwise.

As a practical example -

We depart on the Dover 8M and receive the reply you describe. Having restricted us to 4000ft, the controller takes an inbound onto a right downwind and descends it to 5000ft. If having passed D29 det, we climb, we could be in conflict.

Unusual traffic situation for Gatwick I know. But there are no obstacle or airspace problems ubntil much further down the road so I would sit tight.

Personally, I would consider the phraseology to be poor in this case and "Stop Climb Altitude 4000ft" or "Maintain Altitude 4000ft until advised" could be better.

Finally - if in doubt - ask (if it is too busy for such an important claritication then IMHO it is dangerous).

regards,

DFC

[keithl]

I, too, would maintain 4000ft in this example until re-cleared further. That's because a friend of mine got in trouble with Edinburgh ATC a while back for using the other interpretation on a Grice SID.

Bookworm I think the AIP words "unless otherwise cleared" etc have to be interpreted to include an altitude restriction as a sort of clearance. Could be worded better, I agree.

[4Ohm]

I think this thread highlights just how complex the London SIDS are - there are lots of opportunities for ambiguity. There is differing opinions from both sides here on just this one subject (ATC and Pilots), and there are may more. If swanick lots their radios ????

I can't remember the last time I had to complete a whole SID without headings etc. instructions being given - obviously to make better use of the limited airspace, the current SID's just aren't up to the job of the traffic levels.

I also find the lower altitude limitations very limiting, combine this with complex track keeping requirements (Mostly for noise abatement) all at a busy time of flight - bring in the flaps etc etc.

I can't help but feel that the SID and STAR procedures for the London area need to be radically relooked at.

Higher single level SIDs would relieve work load on both controllers and pilots and also limit the noise problems together with common Transition levels through out the whole of the UK would solve many of the Alt Bust problems.

Any thoughts?

[eyeinthesky]

It's been a while since I did Terminal Control, but I would also expect you to maintain the last cleared altitude (4000ft in this case). What the controller hs done is lift the initial 3000ft cap on the SID, but wants you to maintain 4000ft. He is now taking over the vertical navigation for you, even if you are still following the SID laterally. He might well have traffic at 5000ft in conflict with you.

You quite often hear Thames give the following out of LCY:

"Climb to altitude 4000ft, further with the SID".

This I take to mean that the 3000ft cap under the LL inbounds is lifted and you can go straight to 4000ft, but when you reach further step climbs on the SID you should comply with them. Seems sensible, as they provide you with the altitude to remain inside CAS and also separated from other SIDs from other airfields.

Trouble is, there are too many airfields close together. Imagine what it would be like if they built another one at Cliffe with all its inbound and outbound routes..! :rolleyes:

[max alt]

some more good replies.
If the controller has given me a radar heading,I am off the sid and i will sit tight and await further climb instructions.No problem there.
If I am on the sid I will maintain the initial block altitude untill the specified dme point and then climb in accordance with the published sid,even though i cannot get in on the RT,unless i receive the instruction Maintain. Any controllers have a problem with that.
regards Max Alt.

[bookworm]

If I am on the sid I will maintain the initial block altitude untill the specified dme point and then climb in accordance with the published sid,even though i cannot get in on the RT,unless i receive the instruction Maintain. Any controllers have a problem with that.

Well, I'm not a controller but I don't believe that's what you should do.

First, let's hit the "cannot get through on the RT" bit on the head. If you're in doubt, of course you're going to ask if you can. But the whole point of having clearances is that they provide a plan of action if you cannot communicate further with RT. It's absolutely vital that the clearance is unambiguous in the absence of further instructions or clarification.

My understanding is that a level instruction issued by the controller is an amended clearance that cancels the vertical profile of any previous clearance, including the SID. MATS Pt 1 Section 1 Ch 5 para 6.2 makes that explicit. But I cannot for the life of me find any reference to that in regulatory material that the pilot conventionally has access to -- Annex 2, PANS-OPS, PANS-RAC, UK AIP.

If the controller expects you to resume the SID, they'll need to use a phraseology similar to eyeinthesky's suggestion: "Climb to altitude 4000ft, further with the SID". Actually I don't like that much. At what precise point am I released from the 4000 ft restriction, particularly if there isn't a 4000 ft step in the SID?

Given the emphasis on level busts over the last few years, I'm amazed that there is such a gulf of ambiguity here. :ooh:

[BOAC]

We are drifting away from maxalt's initial question here - he posed the scenario where you are climbing to the initial SID block altitude, and there was NO FURTHER altitude clearance by ATC. It is true - it is ambiguous!

Judging by all the different opinions here, we DO need a 'definitive' from an ATC poster, and perhaps this should be raised by ATC as a safety issue due to the confusion, and terminology needs to be refined?

[brimstone]

When departing on a SID in the London TMA with a stepped climb and on first contact with the controller the pilot passes all the appropriate information including the correct initial altitude, the controller should merely acknowledge the transmission and instruct the pilot to squawk ident without any further mention of altitude unless he or she is amending the clearance.

The instruction "climb" means "climb and maintain" therefore in max alt's example when instructed to "climb to altitude 4000ft", although this is the initial SID altitude, he shouldn't climb above that altitude until positively cleared. I do think, however, that the controller should add a reason why the SID clearance is being changed.

[Right Way Up]

On the LGW Deps we are not actively cleared to a set altitude. We are restricted to altitudes at certain points following the chart. I for one would not climb without clearance, however if the authorities want us to remain at the lower altitude, the clearance we receive on the ground should include an altitude limit to get rid of this ambiguity.

[zkdli]

Max Alt
The situation you give is the usual situation out of luton on compton deps! Bookworm is correct, the clearance given by the controller of "climb to alt 4,000 ft" cancels any previous clearance and therefore you should not climb above that level until given further clearance. There is no phraseology in the mats pt2 that specifically says climb and maintain alt 4,000ft and this difference has given some problems because of the difference with american phraseology of maintain alt etc. However some more prudent controllers will use the word maintain to emphasise that you are not to climb on the SID:O

[Vlad the Impaler]

The reason in this particular instance for the 4000 initial restriction of 26 at gatwick is to position you under the minimum vertical profile of the heathrow dvr sid which is required to be 5000+ around epsom. If on first contact you are told to MAINTAIN 4000 feet then that is what I would expect you to do. If you report, as you should, your cleared and passing altitude when you join the party and I don't tell you otherwise then I would expect you to follow the step climb profile. The major problem is that some pilots (particularly from across the pond) report their cleared level as the final altitude on the sid although they are only climbing to 4000. The other interesting point raised is that if you are given a heading by ATC then technically that DOES remove the vertical restriction as you are being taken off the SID. you really should be given a level instruction with an initial heading even if only to maintain the sid level but this is greatly disputed among ATCO's, some do and some don't. It is up to ATC to be as clear as possible, if it is not clear then ask, if it's too busy to ask then don't do it !!!

[max alt]

Many thanks to all those that have replied.
I was hoping for a definitive answer but it appears from the repies that they are personal interpretations.
This situation does not arise very often,but it does happen.
I thought i knew this,but my view was challenged when flying with a senior colleague.I wanted to remain at initial block(5000) as that was the clearance given by atc(sqauwk ident clb alt 5000),. He was pf and wanted to step to 6000 at the dme point as we had not been taken off the sid.We were unable to clarify due to busy atc.After a short period we received clb instructions.We had a chat about it and our different views became obvious.
I said I would try to find out,
Regards Max alt

[DFC]

As I see the situation, you received two clearances and the second clearance (or ATC instruction) cancells the first.

Your initial clearance was to altitude 5000 in accordance with the SID (which required a step climb).

The second clearance was climb to Altitude 4000. This clearance cancels the first.

Looking at a simlar case in the opposite direction....

ABC123 descend FL130 level goodwood

Next ATC usit clears- ABC123 descend FL070 level holly.

As every ATCO will say, the sceond clearance cancells the requirement to be FL130 by goodwood unless it is repeated as par of the clearance e.g. Descend FL070 level holly cross goodwood FL130 or below.

This is specified in the MATS Part 1.

Perhaps ATC should have said "climb altitude 4000 after dxx det climb altitude 5000" and IMHO that is the only way that I would bust 4000 in the situation you describe.

Regards

DFC

[WMD]

max alt - stay at 5000 if on 1st call you're cleared to 5 (negating the 4 of the SID) - there's usually a good reason for it eg. a LL DET/DVR going over the top of you at 6000 with a heading off EPM.

WMD

PS Come and visit us and see what goes on in that bit of airspace betwix LL and KK !! (We're still at West Drayton for the next few years at least - latest rumour is that we're moving down South in Dec '07)

[brimstone]

max alt - sorry if you don't feel the question has been answered definitively. As I said in my earlier post the instruction "climb" means "climb and maintain" (CAP 413). If you had gone along with your colleague and climbed to 6000ft at the DME point having previously been instructed to "climb to altitude 5000ft" you would have been guilty of busting your level and that really is the end of the story.

If the controller wished you to fly the SID then he would not or should not have mentioned an altitude on first call. By doing so he was relieving you of compliance with the requirements of the SID and if you like taking control of your vertical profile.

[max alt]

Excellent clear post Brim.Many thanks to all those have contributed.I will enlighten said colleague with the facts.
Regards Max alt.:ok: