No Conditional clearances "trial". [Archive]

cossack

19th Mar 2005, 02:22

When I came across here, I thought the lack of conditional clearances (in the runway environment, not on ground where they are used) would be more of a problem than it has turned out to be. On a departures only runway we can use them, but all of the locals don't bother and I haven't noticed a problem with capacity. We still exceed 50/hour/runway in mixed mode comfortably.

As for LAHSO, it is seldom used because fewer carriers allow their crews to accept it. The runways where it can be used here still allow for between 7000 and 9600 feet of landing distance, before the "hold short" point. We tend to avoid runway configurations requiring a crossing operation whenever possible. Its the norm on nights though.

RT loading isn't an issue as most crews know what "monitor tower" means!;)

We can anticipate to a point. That point not being as far as south of the 49th! LGA manages 90/hour on crossing runways with no conditionals, but a lot of anticipation!

Lock n' Load

19th Mar 2005, 02:45

I would say that LAHSO is anticipated separation, not a conditional clearance. If we agree that a conditional clearance is permission/instruction to do something after someone else has completed a stated action (i.e. "after the landing XXX, line up and wait"), then LAHSO isn't conditional! It allows another action to take place independently.
Great way to get out of a hole, incidentally! Had a F18 slotted in nicely to land 34 behind a DH8 on 28 till tower told the F18 to speed up! There went the intersection spacing... Of course, if an aircraft can land on a carrier then 8500 feet to the intersection isn't a problem. The F18 held short for the DH8.:ok:

cambioso

19th Mar 2005, 08:50

Whilst it is interesting to have the input from "over the pond" re. conditional clearances, this rumour concerns a possible UKNATS "trial".
It concerns the proposed banning of the use of conditional line up clearances in ALL instances on the grounds of "safety"....Something to do with some safety survey that some genius carried out post "Linate results"!

I was just wondering if other NATS guys had heard the same thing?
It is only a rumour but it is not an unimaginable scenario given the "headless chicken" environment that appears to pervade at srg these days!!

I for one cannot see how the originator of such a suggestion can have had any experience at a medium/busy traffic level airfield where the conditional line up clearance is an essential "tool" to save R/T loading and time.
In my opinion, for what it is worth, provided that it is properly and unambiguously carried out it is an absolutely safe, orderly, and expeditious procedure.

HEATHROW DIRECTOR

19th Mar 2005, 09:08

Cambioso - agree 100% with what you say but, alas, it's nothing new. How on earth a conditional clearance can be dangerous on a departure runway if the controller knows what he is doing is beyond my comprehension.. Hope it doesn't come into effect before I go on my hols cos Heathrow is going to come to a grinding halt!

(Psss.. be a lot of us "oldies" lurking around on 1st April (!) so if any of you young LL aces want some tips.......)

cossack

19th Mar 2005, 17:56

cambioso

Lock n' Load and myself are both ex-NATS and now have experience of an environment where conditionals are not the norm and seem to be coping just fine without them. If you think our input isn't relevant, so be it.

a medium/busy traffic level airfield where the conditional line up clearance is an essential "tool" to save R/T loading and time
On ground yes; tower, not really. I agree that to stop using them in ground control would be ridiculously restrictive and cumbersome. To not use them in a runway environment is not at all a problem. There are other busy airports in the world other than LL and KK you know. What advantage is there to having 8 or 9 aircraft conditionally lined up on a departure only runway? IMHO, none. Even in mixed-mode, waiting until the arrival is passing the holding point is no sweat, you should only have 1 or 2 arrivalls talking to you and all the departures should be monitoring, not saying hello as they're number 8 in the line-up.

To connect this to Linate is totally bogus. A guy got lost in the fog and there was no ground radar to help. No conditional clearances were involved in this case and no controller would use a conditional clearance at a runway in fog.

Gonzo

19th Mar 2005, 18:25

Cossack, do you use conditional crossing clearances, or is it just line ups not permitted?

At Heathrow we now have experience of not being able to use conditional line ups as much as in the past on one particular runway (09R), due to both closed holding points and new intersections being too close together to use simultaneously due to jet blast (great planning there then!). From looking at the figures myself (not an exhaustive survey by any means), our rate has decreased from approx 45+ to a good hour consisting of 40, along with a corresponding significant increase in workload.

HEATHROW DIRECTOR

19th Mar 2005, 18:26

<<What advantage is there to having 8 or 9 aircraft conditionally lined up on a departure only runway? IMHO, none>>

I can't think of any time I've ever heard 8 or 9 aircraft given conditional clearances - that would be foolhardy. However, a conditional clearance for 2-3 at the holding point gets the crews primed up and it does save R/T time. I would challenge you to achieve the sort of rates Gatwick achieves on a single runway without conditional clearances...

cossack

19th Mar 2005, 20:09

Gonzo and HD

Runway crossings are permitted on ground frequecies here, but the instruction cannot be conditional. Conditional line-ups are permitted when it is a departure-only runway, but the locals don't use them out of habit I think. I still use them occasionally.
a conditional clearance for 2-3 at the holding point gets the crews primed up
A good crew should be primed up when they reach the front of the line up and not need 3 or 4 minutes notice! As soon as I issue a take off clearance the next in line is given "taxy to position" (great phrase, not!) so little if any time is lost.
I would challenge you to achieve the sort of rates Gatwick achieves on a single runway without conditional clearances...
As I said earlier, 50+/hour easily done in mixed mode. Better RT discipline and less chatter would help reduce loading. Tows crossing the runway on tower freq makes more work agreed. Do you issue tows conditional clearances?

benedictus

19th Mar 2005, 20:13

On dual rwy operations (speaking as someone who works on single rwy ops), the advantages of conditioanl clearances, whilst small with each individual movement are immense when totalled over a single day.

At units like LL (and I stand to be corrected), a lot of take off clearances are issued "wheels up" of the previoys departure. With a conditional, the a/c will be already lined up, without, the controller has to issue a line up clearance after the dpearture is clear of the hold, by wheels up he / she might have just got the readback, by take off clearance a whole 30 / 40 seconds could have passed.

In single runway ops in just isn't practical to maintain a high runway utilisation rate without conditional clearances, unless of course the airlines are willing to pay the additional fuel bills for the increased go arounds. On the positive side (if you can call it positive), we get to practice giving out essential traffic information, although this will increase the rt loading and no doubt result in even fewer movements due to not issuing a line up clearance in what would have been a suitable gap

ETOPS

19th Mar 2005, 20:16

Heathrow Director

I've been number 7 on a conditional line up on a few occasions at Heathrow and I'm pretty sure number 9 on one!

Gonzo

19th Mar 2005, 20:16

I can only speak for Heathrow, but some of our CAT I bars are maybe 50m or more from the runway edge, and so with conditionals you can have number 2 over that line and holding just clear of the runway before you clear number 1 for take off. That's part of the reason why our 09R movement rate has gone down, each time you line one up from these points you're losing 10-20 seconds, or more.

Anything crossing the runway; towers, vehicles and aircraft are given conditionals.

terrain safe

19th Mar 2005, 22:04

Interesting idea...NOT

Imagine the amount of time lost telling an AC to line up just as the lander crosses in front of him, while also getting releases from radar, and talking to the inbound now at 4.5 miles. Either the distance between inbounds will be increased or we will get more goarounds.

I know how to make it safer..... one ac in the sky at a time.

Don't these office bods know how an ATC service is provided???:confused: :confused:

Gonzo

19th Mar 2005, 23:29

Exactly; we'd be perfectly happy to comply with any SRG regulation that prevented the use of conditionals, but we'd have to flow accordingly.

HEATHROW DIRECTOR

20th Mar 2005, 07:25

ETOPS.. OK, well I guess things change with time..

I think the office wallahs forget that the guys running the show are professional people. If the front-line controllers are not capable of running the show safely then it raises very serious questions about their training and the sort of standards they are expected to achieve..

eyeinthesky

20th Mar 2005, 12:22

I'm sure we can all make cases for expedition etc which justify the use of certain practices. However, safety is the key, and if safety can be proven to be eroded by the use of practices such as conditional line ups, then we surely need to address these? Many people on other threads have complained how difficult it is to identify exactly which one is the one to which they are conditional, especially when you consider code-share or franchise operations where the company on the callsign might not match the company painted on the side of the aircraft.

Being conditional number 9 is not safe! I bet there are many occasions on which that person at No9 has forgotten how many have gone past and sought clarification from the Tower to make sure they still have the picture. How can having 9 people conditional to each other possible by more expeditious than having only one?

There have been many cases where conditional clearances played a part in accidents. For example, (although there were a whole host of other issues involved) the SH330/MD83 fatal crash at Paris CDG in May 2000 would not have occurred if a conditional clearance had not been used.

Give the trial a chance! It is aimed at safety.

By the way, I am not an 'office wallah'! I have an open mind to issues targetted at improving safety, even if they make us work a little harder.

GT3

20th Mar 2005, 12:37

especially when you consider code-share or franchise operations where the company on the callsign might not match the company painted on the side of the aircraft.

All the more reason to correctly identify the aircraft, we have Star Alliance colour schemes from at least 5 airlines now using LHR, Lauda a/c doing austrian services, snowflake doing SAS etc. As long as you give an unambiguos conditional there should be no problem. However people do sometimes make mistakes but going on the basis it "might" go wrong at some point does that mean we should stop something?

I might crash my car on the way to work, I will still drive. Someone might fly the wrong SIS, doesnt mean I will stop issuing wheels-up take off clearances just incase I loose separation.

Jerricho

20th Mar 2005, 12:56

I think the office wallahs forget that the guys running the show are professional people

Stand by for sweeping generalisation, but from my experience there are more than a few controllers who don the management hat and seem to forget what the sector driver/tower people actually do. And unfortunately there have experienced people who were ver vocal about how much they "were being screwed" by management...............only to do some very similar things with the management hat firmly planted on their head.

Hotel Mode

20th Mar 2005, 16:39

I fly the 744 for BA, there is no way we could be ready to go as the one in front lifts off without a conditional clearance, you need to be over the line and preferably moving when the previous gets cleared. Especailly from full length as the piano keys are very slippery on the nosewheel and you cant do more than 4-5 kts.

DFC

20th Mar 2005, 22:16

I have always found that "Speedbird123 After the Aer Lingus A320 on the north side departs line up and wait" takes up far more R/T time than "Speedbird123 line up".

From a pilot's viewpoint - we are all cleared to the holding point and often join the que some distance before the holding point i.e. we are cleared to a position on the airfield but have to wait until aircraft ahead move out of the way before we get there.

When a runway is used in departure only mode why can we not be told to line up when the threshold is occupied by a departure i.e. when the Aer Lingus in the above example enters the runway, we are told to line up.....same effect as the "clearance" to the hold point...we get there when the other guy moves.

It seems that the current situation of conditionals is effectively doing that because most flights creep forward past the hold bars and into position as soon as possible after the previous flight departs for the reasons given previously.

For mixed use runways simply say "BAW123 line-up" as the lander passes the threshold. Seems to work other places.

If conditional clearances are such an essential requirment why have never heard "BAW123 after the landing B737 vacates cleared take-off" ;)

One way of reducing workload at Heathrow would be the introduction of a requirement to contact the ACC imediately after departure without the requirement for the tower to initiate the frequency change as has been successfully done at other places for years. That alone would reduce the R/T load by 1 call per flight which is lots per day!

Regards,

DFC

Gonzo

20th Mar 2005, 22:36

DFC,

One way of reducing workload at Heathrow would be the introduction of a requirement to contact the ACC imediately after departure without the requirement for the tower to initiate the frequency change

Scenario. You're departing on a southbound route from LHR's 27R. At 1000 feet you switch to 120.52 and start the left turn. At the same time the a/c just about to land on 27L goes around.

Tell me how we would deal with that.

I have always found that "Speedbird123 After the Aer Lingus A320 on the north side departs line up and wait" takes up far more R/T time than "Speedbird123 line up".

But with so many tasks I need to prioritise and undertake whilst doing departures, the conditional gives me the benefit of choosing when to give that transmission.

eyeinthesky

21st Mar 2005, 08:37

QUOTE
However people do sometimes make mistakes but going on the basis it "might" go wrong at some point does that mean we should stop something?
UNQUOTE

Absolutely YES!

Otherwise, what you are saying is that you are operating in a way which you know may be dangerous but you are taking the risk with other people's lives. That is not your choice to make. In aviation we cannot get away with saying: "We know this might go wrong, but we will continue to do it". That way lies disaster.

It is not acceptable in a safety-critical industry to continue to operate in ways we know to be fail dangerous. What's next: "Well 3 miles is plenty of separation, and they all miss, so we'll AIM for 3 miles but if we get less it'll be OK"? Or for aircrew to see the other traffic and take their own separation for climb?

Just because traffic loadings get higher does not mean we can cut corners.

Back to the point: I see the logic for a conditional line up in the form of: "When the one already on the threshold departs, line up" because that is fail-safe. but: "After the third landing, cross", or "After the third from the south side departs, line up" are fail-dangerous.

ATCO Two

21st Mar 2005, 10:43

I cannot button my lip any longer on this one. Perhaps GT3's wording was a little bit dubious, but I know what he meant. ATCOs are NOT in the business of taking risks with other people's lives, and I resent that statement as a slight on my professionalism.

We do not say "when the one of the threshold departs, line up." We identify the subject aircraft by airline/colourscheme and aircraft type to avoid any confusion. If there is still any doubt, good airmanship should dictate that the pilot will query his instructions.

We also do not say, "after the third landing, cross." Conditional runway crossing clearances when landing aircraft are involved are subject to ONE aircraft only. Again that aircraft is accurately described in terms of company/colourscheme and type. That is why aircraft types are so assiduously checked on first contact.

Also we do not say, " after the third from the south side departs, line up". Yet again the subject aircraft will be precisely identified so there can be no confusion. If the pilot crossing the runway is not au fait with the local procedures or geography of the airport, then a conditional clearance will not be used. Simple.

If other airports adopted the strict Heathrow protocols associated with conditional clearances then perhaps ther would be no need for a "trial" such as this. The procedure is SAFE and greatly adds expedition if used correctly. I would not like to see the ability to use conditionals removed for no good reason.

Geffen

21st Mar 2005, 12:49

Does anyone know if this is more than a rumour? or is it just idle speculation?

cambioso

21st Mar 2005, 18:34

An excellent summation of the ongoing scenario ATCO 2 !!

I started this post because there is a rumour (only) going around that "for safety" there may be a two month "trial" that is all.
The idea is shear folly and the eminent posts of those ATCOs that use it for real highlight how it is an essential tool (when properly and unambiguously used).
How many times have we sat at the hold waiting for a line up instruction that is missed because the controller was busy saying something else, or someone checked in on the frequency with his life story!
Gaps are often missed when use of the conditional line up clearance (within the careful constraints so ably summed up by ATCO 2) would have ensured good traffic flow.

They "CANNOT BE SERIOUS!!"

MrApproach

22nd Mar 2005, 06:26

Having a look at your two pages of posts from the other side of the world, the conditional clearance that is most mentioned is the "line up behind" case. Instead of throwing the blonde out with the bubble bath why not tighten up on the phraseology (assuming the examples given are accurate). Use the ICAO recommended format "Behind the [blue][Air France] 737 on final, line up behind" and only allow it after the aircraft on final has been cleared to land. (Sorry USA). That's the way we are forced to do it and regardless of the mouthfull, it gets the aircraft onto the runway more quickly.

HEATHROW DIRECTOR

22nd Mar 2005, 07:06

<<One way of reducing workload at Heathrow would be the introduction of a requirement to contact the ACC imediately after departure without the requirement for the tower to initiate the frequency change as has been successfully done at other places for years. That alone would reduce the R/T load by 1 call per flight which is lots per day!>>

NO NO NO!!! It's the most utterly dangerous procedure ever, especially for a 2-runway airfield. We tried it at Heathrow and it failed because it was too dangerous.. Good communication practice anywhere demands that you do not change frequency a) without being told or b) without stating that you're so doing.

DFC

22nd Mar 2005, 11:36

Gonzo,

Scenario. You're departing on a southbound route from LHR's 27R. At 1000 feet you switch to 120.52 and start the left turn. At the same time the a/c just about to land on 27L goes around.

Same as the scenario - FK50 departs 27R on a dover Sid and just after they are transfered to 120.52, a B747 goes round on 27L.

When a FK50 say departs 27R on a dover SID, with a series of B747s landing on 27L, when do you transfer the guy to the ACC?

If it is say passing 1500ft then why not put the communication transfer into the procedure and have pilots calling the ACC at 1500ft unless told otherwise.

I remember LL before the early turns in the MAP........much more intersting in a go-arround then (pre TCAS as well!!!) :)

----

Heathrow Director,

It would not be something that could be brought in over night but it seems to have worked elsewhere without many collisions or is it only Heathrow Directors that have lots of go-arrounds ;) :)

Or certain favourite airline? ;)

Do they still cheer in TCR when the alarm goes off? :D

Regards,

DFC

Gonzo

22nd Mar 2005, 12:33

DFC,

Same as the scenario - FK50 departs 27R on a dover Sid and just after they are transfered to 120.52, a B747 goes round on 27L.

No problem, because you either wait until it's 'clean' against a possible missed approach before you chuck it, or you get a level check before you chuck it so if there is a go-around you can tell arrivals what level they're safe up to.

In the case you mention I'd wait until he's at 2.5 at least.

HEATHROW DIRECTOR

22nd Mar 2005, 14:58

DFC... can you explain why simply waiting for ATC to tell you to change isn't acceptable... and don't give me the old chestnut about cockpit workload! Over the years we trialled a number of procedures at the request of pilots but none worked and we always reverted to the sytem of telling the guy when to switch..

In my opinion, and experience, it is eminently sensible for traffic in the immediate vicinity of an aerodrome to be in contact with the Tower until the Tower is happy to transfer it to the next frequency. 99 times out of 100 it will be as soon as wheels are up.... but that odd occasion when it is necessary to be talking to you it might save lives.

The worst airmiss I ever saw was caused by a pilot changing frequency without being told, probably because he thought he was at an airfield which has that unsafe procedure. PM me if you want the story.

Silk Merchant

22nd Mar 2005, 20:07

First post, so be gentle with me.

Back to the original topic, the problem of runway incursions has been growing at Heathrow for the last few years. To give some perspective they are mostly of the "lined up in the wrong order" variety which can mean some rapid braking for the crew who should have been lining up and a minute or so of departure time lost, but no-one gets hurt. As a percentage of the total movements figure I guess it's not a lot but as a bald statistic it is a big number which has got the attention of the "office wallahs". The issue needs to be addressed or a ban on conditional clearances will be the result.

The answer lies (for Heathrow) with the Air Departures ATCO and the crews of aircraft in the holding area.

ATCOs - keep to a sensible number of conditionals, ensure your instructions can be easily understood and listen to the readback

Pilots - listen out for your clearance, ask for clarification if it doesn't make sense and please try not to badger us about your sequence number. We know you are there, and are working are socks off to get every one away with the minum overall delay. To get the best use out of the runway this may mean several aircraft get away ahead of you but the overall delay is kept to a minimum.

Speaking personally, it dosen't bother me whether I am allowed to use conditional clearances or not. I suspect the inability to use conditionals at Heathrow will result in a reduction of runway capacity. This may only be 2 or 3 an hour, but that could add up to 45 departures lost each day.

We, at the sharp end, have it in our power to keep things as they are. Remove the statistics and the office wallahs will forget about this.

Silk Merchant

Gonzo

22nd Mar 2005, 20:25

Silk Merchant.

I agree 100%....However, who among us believe that our declared capacity would decrease? Of course, it should, but would it really?

And I find the phrase "The next aircraft to ask for its sequence will be last" quickly gives you a period of silence! :E

White Hart

22nd Mar 2005, 21:40

Silk Merchant

Please check your PMs

DFC

22nd Mar 2005, 22:08

Heathrow Director,

can you explain why simply waiting for ATC to tell you to change isn't acceptable

I never said that it wasn't acceptable. In fact it is perfectly acceptable.

The ATCOs seem to use the conditional line-up as a method of doing a number of tasks in an available time period to avoid other tasks clashing with those tasks at a later time. For example - use a conditional clearance now while you have the time so that you can in 30 seconds transfer the airbourne aircraft to the ACC without having to go back and tell the crew to line up........getting two things done at once.

If the "automatic transfer" was scheduled for say 2000ft then the tower could leave the aircraft to transfer at 2000ft and get on with line-up clearances, crossing clearances and coordination.

When does the transfer of control from the tower to APP/ACC (not transfer of comms) take place for departing flights at Heathrow?

I always believed that the transfer took place as soon as the aircraft was airbourne for flights in IMC?

Anyway it was just an idea that could save r/t time which will probably be overtaken by datalink - you press the transfer button and the message in the cockpit reads - 13317 bye!

Regards,

DFC

cambioso

23rd Mar 2005, 04:38

Very interesting debate chaps.......but.....has anyone else heard (or know) whether this is just a rumour or is there a basis of fact that use of conditional clearances is to cease "for a trial period"?

HEATHROW DIRECTOR

23rd Mar 2005, 07:38

DFC... If the tried, tested and safe method of Tower transferring aircraft when the controller is ready is acceptable, why change it? Good communication practice is for an instruction to be issued for a frequency change and for a proper acknowledgement to be received. The Air Departures position at Heathrow Tower is not an over-busy postion and a properly trained and experienced controller should be well capable of deciding the correct priority for his tasks to achieve the end result with the minimum of fuss and the maximum safety.. but he can't do that if he is not able to communicate with aircraft.

Transfer at 2000ft? We trialled "Contact departure 90 seconds after rolling", which is pretty close, because some pilots reckoned they couldn't cope with noise abatement and a simultaneous frequency change. I had more than one frantic call from radar asking if I still had xxx - it was passing Epsom and hadn't changed freq! Other times I needed to talk to a crew soon after take-off but they'd gone...

We trialled "contact departure when airborne".. and, believe it or not, one very well known European airline crew changed frequency whilst lined up... The radar man said "squawk ident and climb to 6000ft" so they took off, much to the amazement of the Heathrow Tower man. Many other crews contacted LATCC before take-off too, even announcing that they were "number xx at the holding point". (Maybe they were the same guys who called ready for start-up whilst their pax were still checking in?!)

"Transfer of control" at Heathrow happens when the outbound aircraft makes contact with ACC. There is no physical transfer, nor, with one or two exceptions, communication 'twixt the controllers; it's all done "blind". The London Control guy has all the information about the flight and a display indicating when the a/c is cleared for take and when it is airborne so he is anticipating a call. The Tower man instructs the crew to change frequency - and thereby relinquishes control - when it is safe to do so. Whether it's IMC makes no difference - in fact in LVPs the Tower man may have to retain control for longer to sort out go-arounds.

CAP670

25th Mar 2005, 10:39

Does anyone know if this is more than a rumour? or is it just idle speculation?

I'm not aware of any such suggested 'trial' although the issue of runway incursions is a 'hot [safety] topic' for both the UK CAA's SRG, the FAA and Eurocontrol, and also for NATS, and the statistics in the UK at least seem to show that the majority of runway incursion incidents are associated with conditional clearances.

However, the conditional clearances for departures used at some High Intensity Runway Ops airports and LHR is one, differ from the conditional clearances used at most other UK airports i.e. the latter do not normally give conditional clearances against another departure which for example, might be # 8 in the take-off queue.

The issue isn't that simple because there are also conditional clearances to cross runways after landing or departing aircraft and to line up for an intersection departure after a full-length departure. Thus, some conditional clearance scenarios are more exposed to risk than others.

Airport layout, runway access, taxiway configuration and positioning of holding areas (if provided) are all factors that affect conditional clearances and make 'em more or less desirable depending on location.

As a point of correction, for an active runway, conditional clearances must only be issued in respect of single aircraft and the next one in the sequence i.e. the next to depart or land. However, if the subject aircraft is taxiing out i.e. is neither landing or taking off, nor on the runway, then this rule doesn't apply.

Certainly, if conditional clearances were prohibited, then the traffic flows at LHR, LGW, MAN, STN, BHX, EDI, LTN and GLA (as NATS' busiest airfield locations) would take a hit, make no mistake! And neither the airport companies nor the airlines (especially the low-cost sector) would be pleased about it.

;)

Spitoon

25th Mar 2005, 11:35

To give some perspective they are mostly of the "lined up in the wrong order" variety which can mean some rapid braking for the crew who should have been lining up and a minute or so of departure time lost, but no-one gets hurt. I've never worked at Heathrow but I know there are strongly held views about the 'essential' use of conditionals to maintain movement rates. Personally I don't like conditional clearances and don't use them unless it is truly necessary. Why? - even with this limited use, I have seen many misunderstandings, even where there are no language difficulties. And I don't think I'm the common factor :D

The fact that these things happen and no-one gets hurt is down to luck to a great extent. I recall reading something a while back that said that conditional clearances were contributory factors in a large proportion of runway incursions. If this is true, it needs investigation. I would far rather consider whether conditionals are a good thing or not based on experience gained in a controlled trial situation and not simply on a macho 'the only way Heathrow can operate is with dozens of conditional clearances' view expressed by a few people.

I'll now duck in prepration for the assault of claims it's just sour grapes and that I'm not macho enough to cut it at Heathrow!

Gonzo

25th Mar 2005, 12:19

Spitoon,

I don't think anyone has said that...

a macho 'the only way Heathrow can operate is with dozens of conditional clearances'

It would be impossible to maintain our movements rates if we were prevented from using conditionals. No ATCO would protest if SRG made a ruling outlawing their use, we would look for a decrease in the airfields declared capacity in that case. Less traffic would make the whole operation less susceptible to 'friction'; work in progress, lack of dispatchers to turn the guidance on etc etc, creates loads of delays each day.

Anyone who knows me can attest to my lack of 'macho-ness'!!! But that doesn't stop you coming for a visit to see for yourself! :ok:

This is a crisis

25th Mar 2005, 12:42

Think you will find that this all stems from ATSIN 41

Recommended Action
4.1 Organisations that provide aerodrome control services should review local
procedures and practices relating to the use of conditional clearances in order to
satisfy themselves that the risks of such operations are adequately controlled. It is
expected that this will form part of an aerodrome organisation's on-going risk
assessment and safety management process.
4.2 Any change identified as a result of this review may be subject to audit by the
Regional Manager for ATS Safety Regulation before implementation.

We did a review at our unit and made some changes like not using conditionals at night or with vehicles.

CAP670

25th Mar 2005, 15:12

hold at SATAN

25th Mar 2005, 15:48

Rumour(virtually fact) has it that big wig LL is very anti-conditionals and wants to get rid of it... why? who the devil knows! :mad:

Stopping conditionals will definitely reduce movements. plugged in for an hour, a deps controller will invariably give late line ups whilst being distacted with phone calls to approach, svfr etc or co-ordination. We don\'t just say "cleared for take off" you know. The time taken to give the specific "line up now" instruction would otherwise have been used by aircraft to start lining up, had a conditional been given. May be a few seconds, but they soon add up to minutes.

Spitoon

25th Mar 2005, 17:15

The discussion does indeed flow from ATSIN 41 but unfortunately, as is so often the case with the CAA/SRG, it issues a missive and then expects industry to balance the sometimes conflicting demands of productivity (i.e. expedition, capacity and service delivery) with safety. So are you saying that you don't take account of safety unless the CAA points it out?

There will always be a balance between safety, capacity and loads of other factors. For as long as I've been in the game there's been a bottom line that it must be safe first and foremost. Does this not apply at Heathrow for some reason?

But it's a balance and there's more than one way to skin a cat (sorry, cant think of any other metaphors). Isn't it better that the CAA say take a look at your airport or procedures or whatever and make sure they're as good as they can be than no more conditional clearances?

P.S. Gonzo, sorry I was being a touch provocative - just bored with a day off when so many others have too! Thanks for the offer but I have watched in the past - very impressive it is too, but I'm still not a great beliver in conditionals. Perhaps the level of experience of pilots and drivers at LL is better than at some of the places that I've seen things go wrong. Maybe I've just been unlucky. But I guess we all develop preferences in how we do the job.

CAP670

25th Mar 2005, 20:07

So are you saying that you don't take account of safety unless the CAA points it out?

Certainly NOT!!

But...if the CAA (which is after all, supposed to be the industry Safety Regulator) has evidence that a particular procedure is potentially unsafe/less safe than it could be, surely the CAA should prohibit that procedure, not issue 'guidance' which in reality means passing the buck to industry?

Conditional clearances are not in themselves unsafe or even less safe if applied correctly and sensibly; but they might be under certain combinations of circumstances.

;)

Gonzo

25th Mar 2005, 20:10

Spitoon,

Hey, don't worry. Being provocative is often the only way to point something out, as I know very well. :ok:

PPRuNe Radar

26th Mar 2005, 00:47

But...if the CAA (which is after all, supposed to be the industry Safety Regulator) has evidence that a particular procedure is potentially unsafe/less safe than it could be, surely the CAA should prohibit that procedure, not issue 'guidance' which in reality means passing the buck to industry?

A very timely comment :}

NATS is now using a new safety occurence report form which can also double as a CA1261 (MOR). On the new form there is a box available overleaf in which the reporter may suggest how the occurence can be prevented in the future. SRG have (according to NATS managers anyway) stated that they do not wish to be sent the second page of the form since if they received a suggestion then they would have to act upon it and follow it up ..... doh, is that not their fecking job ??

Sometimes you wonder what is the point of having a regulator - who will never make decisions, never be pro-active, never act on what the industry is telling them, and that's just for starters.

HEATHROW DIRECTOR

26th Mar 2005, 07:26

<<Rumour(virtually fact) has it that big wig LL is very anti-conditionals and wants to get rid of it... why? who the devil knows!>>

If that is true it reveals a worrying lack of confidence in his controllers or the aircrews using the place. During my 22 years at Heathrow Tower I can only recall one runway incursion when I was on watch. Incredibly it was just a few days after the Tenerife incident. An aircraft heading for the south side taxied straight across 09R without clearance in the path of a departure. How does one legislate against that? Are incursions becoming more frequent to the exent that airfield movement rates will have to suffer? I can't imagine the airlines liking that too much.

Spitoon: Of course the prime aim is safety but we're all humans, including you and me! I have seen some utterly ludicrous procedures introduced at Heathrow because either aircrew or controllers made mistakes and knee-jerk reactions by management caused chaos. Some of the procedures are still in force but others simply disappeared under a pile of commonsense.

ebenezer

26th Mar 2005, 12:10

Rumour(virtually fact) has it that big wig LL is very anti-conditionals and wants to get rid of it... why? who the devil knows

Forgive me for pointing out the obvious BUT the ATC/airport world doesn't revolve around Heathrow.

If some big knob at Heathrow has misgivings about conditional clearances at that unit then the issue and the specifics at Heathrow, should be addressed there, not broad-brushed across everyone's patch.

Conditional clearances ARE NOT unsafe provided that they're used sensibly and iaw the MATS Part 1 and/or MATS Part 2.

If they are ever proved to be unsafe, then I'm with CAP670 and PPRuNe Radar and would say that it's the CAA Safety Regulator's job to put a stop to everyone using them - but this would mean the Ministry men actually being proactive!

As the CAA hasn't banned their use, it's reasonable to deduce that conditional clearances if used correctly are OK, in which case why would NATS (or any other ATC company) want to suspend or prevent their ATCOs from using them, especially when at the busiest locations, they're an essential tool to keep things moving and meet the capacity targets which incidentally, aren't set by ATC or ATCOs but by the airports...?

:hmm:

terrain safe

26th Mar 2005, 14:43

Aren't conditional clearances in the MATS pt1? I can't remember reading anything about them in the pt2 (don't tell my LCE) so how can they be stopped? The only local conditional clearances are things such as 'after the landing cleared to land' and 'after the departing cleared to land'. I don't see how SRG can ban conditional line ups, crossings etc locally. They have to be banned on a national level only. Some Jobsworth should leave the office and find a headset.

West Coast

26th Mar 2005, 16:30

For my own edification, why do some of you believe traffic will (in the long term, if so) be negatively affected. Is there something I don't see that would prevent adaptation in time?

Gonzo

26th Mar 2005, 17:43

I can only speak for Heathrow, but as I said earlier, many of our Cat I holding points are 50m or more from the runway edge (ie. SB1, S11). Using conditional line ups enables a/c to be much nearer the runway, hence they are fully lined up and ready to roll when the one ahead lifts off. Using conditional crossing clearances allows crews to adjust their taxi speeds so that they are rolling at speed when the landing or departing a/c crosses their nose, thus getting them over in a tighter gap. Due to work in progress in the 09R holding area, we currently are less able to use conditional line ups than we were, and our figures have gone down. As has been said previously, conditionals allow us to make an r/t transmission at our convenience, get it out the way, so that we are free to concentrate on the myriad other tasks, so our depature rate stays high.

ShooTheGap

26th Mar 2005, 19:58

It seems that there is only one ATC world and it should be according to the UK CAA. Spacing based on time at an airport like Heathrow??? welcome to 2005. Time is dead, Radar is in! Frankly I am far from impressed at the operation and dare to say that it would never move the numbers of North american airports.
As to conditional clearances, if you have something better to do than to scan your runway when you issue a clearance to enter the active then I would like you to look for another Job or come and work Some real airports across the pond where they do not and never would think of issuing a conditional clearance for anything! While we are at it...can you kill the "land after clearances". Not sure if it will work, but hey go ahead and try to land after.... your call captain!

Like I said Tony likes George, they should also discuss how the boys do it here without conditional...

terrain safe

26th Mar 2005, 20:18

ShooTheGap: you are just begging for a response that involves willy waving but I can't be bothered. Going to watch Graeme Norton cos he's soo Macho compared to a UK tower ATCO like me............

HEATHROW DIRECTOR

26th Mar 2005, 20:27

Shoo.. If you understood some of the problems we have with lack of airspace, noise restrictions, etc., you might be qualified to offer an opinion... but you're not so please leave this discussion to those it concerns. Would I tell you how to run Chicago or Atlanta? Thanks.

Gonzo

26th Mar 2005, 22:43

Shoo,

I'm terribly sorry, but you'll have to repeat your post in layman's terms, as I have no idea what you're talking about. Who mentioned separation?

You say that the US don't use conditionals....what is 'no.4, cleared to land' if not a conditional?

cossack

27th Mar 2005, 03:35

Gonzo
I'm not taking sides just clarification.
what is 'no.4, cleared to land' if not a conditional?
It is anticipated separation as there is no "condition" attached. When you give an "after the landing/departing" clearance you're passing the responsibility to the pilot. With anticipated separation, the controller retains responsibility as the runway must be clear by the time the arrival reaches the threshold. Clearing somebody to land when they're other than number 1 allows the controller to get on with something else, like traffic on one of the other runways s/he's responsible for. Kind of like your argument for priorities just in a different order.

ShooTheGap has a point about departures separations based on time though, ;) but that should be a different thread.

Gonzo

27th Mar 2005, 05:33

No condition? What about the one ahead vacating, surely that's a condition? To my mind we're into semantics now, as 'anticipated' and 'conditional' are one and the same.

The Controller retains responsibility for all the other conditionals that we use.

Shoo,

can you kill the "land after clearances". Not sure if it will work, but hey go ahead and try to land after

I hope you're not getting confused by 'land after' and 'after the landed, cleared to land'. :ok:

HEATHROW DIRECTOR

27th Mar 2005, 06:21

<<When you give an "after the landing/departing" clearance you're passing the responsibility to the pilot. >>

No sir!! You're thinking of the "Land after", which places responsibility on the pilot and does not take account of distances involved, runway conditions, etc. The "after the landing/departing" clearance has certain parameters attached to it which ATC take into account before isssuing it. If those parameters are not met a go-around may be given.

ebenezer

27th Mar 2005, 07:19

When you give an "after the landing/departing" clearance you're passing the responsibility to the pilot.

Sorry Cossack, but for the benefit of the flyer readers, as LHR Director says, you're incorrect!

The modified landing clearances used at for example, Heathrow, Gatwick and Manchester in the UK require that ATC takes account of the position or anticipated position on the runway of the departing or landed aircraft, relative to that runway's threshold. Thus, separation or anticipated separation remains the responsibility of ATC. This is not by the way, an exclusively British procedure but one that is recommended for European use in order to maximise runway utilisation.

The more basic 'land after' procedure as prescribed in the UK MATS Part 1 is where the responsibility for maintaining separation passes to the pilot of the landing aircraft which is why he/she must be able to see the landed aircraft ahead.

Irrespective of whether or not US ATCOs manage to 'push more tin' than their UK counterparts (for which there may well be good and not-so-good reasons), the original subject of this thread - the possible suspension by NATS of the use of conditional clearances - must surely remain an issue for the UK CAA to determine.

If NATS does suspend their use, is it not in effect saying that it doesn't accept that this CAA-approved (i.e. MATS Part 1) methodology is either safe or acceptable?

In which case, isn't this taking self-regulation to the ultimate extreme and thus, effectively making the CAA's SRG superflous (it's already been demoted by the EU into a mere a 'National Supervising Authority') to the debate??

Maybe this is what NATS' 21 Destinations # 6 actually means in practice!

:E

Lock n' Load

27th Mar 2005, 08:56

Ignoring for a moment the responsibility question, I have to disagree with Gonzo when he asserts that conditionals and anticipated separation are the same thing. They're not.
A conditional requires a pilot to react to a stated condition. Anticipated requires only that he/she carry out an instruction unless subsequently told not to.
As for the rest of the thread thus far, I agree with those who say that conditionals shouldn't go as far as "after the ninth landing xxx, line up and wait". When an active runway was involved, I never gave a conditional clearance based on anything other than the first landing aircraft. I also, though it wasn't a requirement, gave a landing clearance before the conditional line up which was subject to that landing. I did, however, give conditional line ups to more than one aircraft when only departures were involved.
On GMC, it's a different story. I'd quite happily give 6 or 7 conditional clearances which all came together when aircraft parked or taxied out. The only times it didn't work were when an occupied stand was allocated (no view from EGPH tower...) or once, when a 737 belonging to a low cost airline based near, but not in, the UK intentionally pushed back before the aircraft he was waiting for had parked. I had him pull back on to stand.:p

cossack

27th Mar 2005, 15:11

Gonzo, HD and ebenezer

It was late, I typed differently to what I was thinking. :O

Let's try to clarify:

A "land after" transfers the onus to the pilot, he can accept or decline it. It won't save any RT time if he declines it and you have to discuss the options! The aircraft ahead can still be on the runway when he touches down, albeit some way down it.

An "after the landing/departing" does not transfer responsibility to the pilot. This is basically what happens with anticipated separation without a different phrase being used. Parameters have to be met by the time the arriving aircraft crosses the threshold. Previous arrival off the runway/departing aircraft is airborne for the clearance to be valid, otherwise a missed approach will be given.

Are you surprised that pilots get confused though? 3 different ways of being cleared to land based on a different use of the same words. Not easy for non-native speakers to understand the nuances and responsibilities involved, and I include Americans in that!

It is not a conditional clearance though as there is no "after" or "behind".

How many times have you given a "land after" clearance and had it read back with "cleared to land"?

So, when does this all start, or is it still a rumour?

Moral: Don't post very late at night unless you want to be proved wrong in the morning!

Gonzo

27th Mar 2005, 15:19

I fully admit it is confusing, having three types of 'landing instruction', so that's why I don't use the others, apart from when a BAW or BMA might say 'we're happy to land after'.

L and L,

A conditional requires a pilot to react to a stated condition.

Surely 'no.4, cleared to land' is the same as saying 'after the one ahead of you vacates, you are cleared to land'. There's a condition.

Anticipated requires only that he/she carry out an instruction unless subsequently told not to.

"After the departing 737, line up and wait".......he/she will carry out that instruction unless subsequently told not to.

I'm still struggling to see the difference. Unless you're saying that if given 'no.4 cleared to land' he would land even if the one ahead hadn't vacated yet and the ATCO forgot to send him round.

Lock n' Load

27th Mar 2005, 16:20

Gonzo....
"Unless you're saying that if given 'no.4 cleared to land' he would land even if the one ahead hadn't vacated yet and the ATCO forgot to send him round."
Yup, that's pretty much what I'm saying. It could be IMC after all.
Bear in mind that landing clearances are only a part of anticipated separation. There are take off clearances given to an aircraft on one runway before an aircraft on the crossing runway has even reached the intersection, and the expectation is that the pilot WILL begin his take off roll straight away, and that the other aircraft will roll through the intersection ahead of him. There are both take off and landing clearances given when an aircraft on a crossing runway has been cleared to land and hold short. All of these ANTICIPATE that no paint will be traded.
If a helo operating VFR wanted to cross an active runway, and even if I was 100% sure that giving him a crossing clearance straight away would put him well behind a landing or departing aircraft, in the UK I would have to say "after the landing/departing XXX, cross runway XX". That would be conditional! In North America, I wouldn't have to add the condition, as instead I would be ANTICIPATING that he would be well behind the lander/departure.
I would have to say that in general I prefer conditionals to anticipated separation. They are more fail-safe and they keep other pilots in the picture, especially the ones on whom the conditions are based.

Gonzo

27th Mar 2005, 16:34

Thanks L an L.

Yup, that's pretty much what I'm saying. It could be IMC after all.

Jeeez. OK. Didn't realise that it could also be used in IMC!

Interesting.

DFC

28th Mar 2005, 19:14

ebenezer,

"If NATS does suspend their use, is it not in effect saying that it doesn't accept that this CAA-approved (i.e. MATS Part 1) methodology is either safe or acceptable?"

No.

If one was to use that logic then any pilot who used higher minima for an instrument approach than those published by the CAA would fall into the same category.

-----

I must admit thyat "Number 4 cleared to land" never sits easy with us. However one must look at the whole picture.

On departure, we are cleared to destination runway despite the fact that such a course of action would without ATC intervention would cause aluminium rain somewhere down route.

Enroute, we are cleared to beacons at levels that are occupied by other aircraft also routing to those beacons from different directions at the same level and at the same time.

However, ATC rely on the fact that we and/or the other aircraft will be in contact with them in good time and they can work some radar magic to make us miss..........but what if we both don't call?

Number 4 cleared to land can not be less safe than the above because in order to issue such a statement, we must be in communication and furthermore unlike the enroute situation, we know about all the other flights.

Anticipated separation may not be nice but it seems to work even in the UK.

Regards,

DFC

Dances with Boffins

29th Mar 2005, 09:33

No 4 Cleared to Land

With all the fixation during ATCO training focussed on "What would happen if you lost R/T now" the above command doesn't sit too safe with me as an ex-flyer. if I'm cleared to land, then land I bloody well will. If following the above instruction from ATC some dire misfortune befalls No 1 or 2 [tyre burst anyone?] you are going to have to pray that the frequency remains clear whilst you then instruct No3, me and whoever else you've just given the runway to to Go-around.

Just seems like an accident waiting to happen, irrespective of how many redundant systems you have in place.

There's conditional, an' there's conditional. The above has more conditiona attached than a night at Michael Jackson's house....

bekolblockage

29th Mar 2005, 10:04

I've never understood the logic behind the "No 4 Cleared to Land" instruction either.
Why do you guys in N A bother??
Why doesn't everyone just presume they're cleared to land unless told otherwise - surely that would save you a lot more R/T and follow the same logic.

West Coast

30th Mar 2005, 15:04

"What would happen if you lost R/T now"

Looking at some of the scenarios played out here, the same RT failure would play havoc with some of the conditional clearances issued over there. You seek some sort of absolute guarantee that doesn't exist. I don't see some fail safe that some might presume exists from your way of doing it.

From a pilots perspective I like it. During an approach to mins I can remain focused on the approach and not worrying if I'll get a clearance.