Minimum seperation between IFR and VFR

[littco]

Can someone confirm the minimum separation between an IFR flight on a standard instrument departure from a non radar equiped airfield and a VFR flight flying through the over head of the same airfield?

The initial climb clearance for the IFR SID is 2400ft while the VFR flight is asked to fly through the over head at not less than 2300ft. leaving a 100ft maximum seperation. The IFR SID and VFR flights course, means the IFR aircraft flys directly over the VFR aircraft at the said heights.. Is this correct?

[Life's a Beech]

There is no separation given between IFR and VFR traffic in that situation.

[littco]

Thank you for the reply..I'm very suprised though

So is it reliant on visual seperation between the 2 aircraft? What happens if the SID initially takes you away from the VFR traffic but then turns you into it.. Neither one of you can clearly see the other? Believe me flying a 100ft over a piper warrior is a little too close for comfort!!

I know TCAS may be able to offer an RA for the IFR traffic but it needs to be fitted in the first place.

[Spitoon]

This is a fairly fundamental part of flying. The class of airspace may affect the details of the answer but, essentially, ATC provides separation between IFR aircraft. There is no separation to be applied between VFR flights or between IFR and VFR. ATC should, subject to workload etc., give the IFR flight traffic information on the VFR flight.

Having said that, many controllers will build some space between VFR and IFR flights by means of the clearances issued to the relevant flights. This is partly because it makes things safer and because it reduces the need to pass traffic information.

It must be said that the airspace allocation used in the UK makes the mixing of IFR and VFR flights more common than in other States.

You asked the question about separation - and you have an answer. Whether the situation you describe is good controlling technique - or the optimum way to handle the traffic situation - may be questionable but that's another issue.

[Del Prado]

what class of airspace? IFR and VFR are only separated in class B and C (I think!)
In a similar scenario even traffic info will not be available if the warrior is unknown (eg operating a few miles from the end of the runway but outside the ATZ and in class G airspace.)

There's an interesting report in the latest CHIRP about pilot's not being aware of the different classes of airspace.

Re TCAS. not much use if the warrior is not SSR equipped.

[2 sheds]

Littco

Assuming you are referring to a class of airspace where separation is not effected by ATC between VFR and IFR flights, and that the VFR traffic is known to ATC, each aircraft would be passed traffic information on the other if it were evident that they could conflict. In the case of the departure, this would invariably be before take-off - and you could always elect to delay until the potential for confliction had passed .

You refer to a SID, but at a non-radar airport? And going to only 2400 ft ? Either way, you can always request to deviate from the departure - or request an alternative clearance - for safety reasons.

2 s

[SINGAPURCANAC]

My two cents..
I have been working in two different enviroment. The first part of carrier without airspace classification ,i.e. each a/c regardless of flight rules was separated by 1000ft/300m(whatever is more applicable) or any other ICAO based minimum.
Later we "dicovered" airspace classification and we felt like "new born" . Since than, no separation were applicable in classes D,E,F,G , between IFR/VFR.
But you always have to have some "personal" separation. IFR departing on SID and VFR orbiting on rwy hdg 2Nm at 1000 ft. It si not mandatory to separate them but as my friend told me " I would separate them due to religious reasons":ok:

[littco]

Thanks guys.

Spitoon.. That's exactly the answer I was looking for, thank you.

[DFC]

Where does the 100ft separation mentioned come from?

IFR departure climbing to 2400ft against a VFR flight not below 2300ft says to me that the VFR flight and the IFR flight could both be at 2400ft at some stage with those clearances.

The safest place for an IFR flight to be is in solid IMC. Less VFR traffic in there to worry about.

Yes I did say "less"!

Regards,

DFC

[littco]

DFC

I agree. The 100ft came from a Maximum. The VFR flight has been told not to go below 2300ft the TMA starts at 2500ft, where's the best place he's going to fly.. In the middle of the two. Where's the clearance, in the middle. I appreciate that we're in class G airspace and there is no seperation other than visually but I just am concerned that we can get so close.. As you say IMC is better, Next time though I will certainly allow more spacing before departure if there is any doubt.

[2 sheds]

With respect, the discussion about the levels is irrelevant - one of the aircraft is VFR, and traffic information has been, presumably, passed to each. Therefore, if you get adjacent to each other, it will be in VMC (as applicable to at least one of you!) That's the name of the game. The unfortunate bottom line is - if you don't like it (and that is quite understandable) - don't fly there, or better still start lobbying to get CAS, radar service to VFRs, better procedures etc etc..

[Dizzee Rascal]

littco, which airport are you referring to? There maybe some folk on here who work at the airport you mention!

[littco]

It was Biggin Hill..

But I would like to point out that just because I asked this in the ATC ISSUE section that I am not saying this is anyway an ATC issue, I just figured it was the best place to ask and hopefully some light maybe shed on it, which it has and am grateful for.

[bookworm]

Biggin Hill has no SID. You were in class G airspace and as such, you were not separated from other IFR flights, let alone VFR ones, unless those IFR flights happened to be working the same unit.

[Dizzee Rascal]

I thought the situation sounded familiar!

As said by others on here, there is no separation between VFR and IFR whether the IFR is flying on a SDR* or not, in class G airspace.

In the situation you describe, I would imagine the ATCO had issued specific traffic information to both parties and quite possibly the ATCO may have slightly delayed the departure until s/he could see the over flight and or was certain that there was no risk of collision, which is what an ATC service is all about after all.

Regarding the not less than 2,300ft part, normally an over flight is asked to overfly not below 2,000ft (providing VMC can still be maintained of course) this is to keep the over flight out of the way of the Tower ATCOs circuit traffic and above the final approach and immediate climb out which is the whole point of having an ATZ however, I suspect one the few trainees may have been on at the time and possibly slipped up and asked for the wrong level, I suspect this was discussed during the trainee's de-brief by his or her OJTI.

I've personally never heard anyone restricting a VFR over flight to not below 2,300ft given the fact that they also can't go above 2,400ft so I suspect a trainee must have been on at the time.

*Standard Departure Route similar to a SID but for us poor people that do not have controlled airspace!

[littco]

Dizzee Rascal,

Thanks for the Info. I guess by the way you say it,it sounded familiar and it's not the 1st time this has happened..

Have to say where as we normally are cleared for a right at 1mile we where actually told prior to the takeoff clearance to turn at 1.5 miles, we did actually ask ATC for confirmation of this before we started rolling. So ATC did a good job of giving us extra spacing however, I guess though that it just happened we where at nearly the same point at the same time due to a number of other factors.


Also, pilots must follow SID's(some deviation allowing)... does that mean for an SDR we don't?? can we choose not to turn at 1 mile if we decide it's better...

[Life's a Beech]

Mostly correct, bookworm. Thames radar and Biggin Approach will co-ordinate traffic so ensure separation, but that is a local agreement and not guaranteed by the requirements that units are working to.

[Dizzee Rascal]

Thanks for the Info. I guess by the way you say it sounded familiar it's not the 1st time this has happened..
Correct, its not the first time a VFR over flight and an IFR departure have been operating at the same time, it wont be the last!
Where as we normally are cleared for a right turn at 1mile we where actually told prior to the takeoff clearance to turn at 1.5 miles, we did actually ask ATC for confirmation of this before we started rolling. I guess though that it just happened we where at the same point at the same time..
It sounds like RWY03 was in use therefore right turn at 1NM for jets, turbo-fan and turbo-props, 1.5NM for everything else. When turning right from any other RWY its at 1NM.
lets hope in future no-one gets any closer!
See and be seen when operating in class G, remember, there will be unknown traffic with no transponder operating outside of an ATZ even at night and in IMC at all levels along the route of the SDR that you might be flying on.
can we choose not to turn at 1 mile if we decide it's better...
Better for who?
The AIP entry says: These procedures may at any time be departed from to the extent necessary for avoiding immediate danger. ATC will expect you to conform to the SDR unless you are avoiding immediate danger but not to get to your destination faster.

[littco]

Better for who?
The AIP entry says: These procedures may at any time be departed from to the extent necessary for avoiding immediate danger. ATC will expect you to conform to the SDR unless you are avoiding immediate danger but not to get to your destination faster.

Thanks Dizzee.. what I needed to know..

[Grum]

Thought ATC would be the best people to ask here.

Whilst waiting on the runway, i was informed of traffic routing through the overhead at 2300 feet. I ackowledged that i had the traffic in sight. Was then cleared for take-off to follow the SID which climbs me to 2400 feet. The first part of the departure took me in a completely different direction from the traffic and so i lost sight of it. The SID then turned us back towards the traffic which we struggled to locate until we flew over the top of him by 100 feet.:ooh:

Additional information is that I was in a light jet that is not required to have TCAS! A daft loop hole in the legislation. Conditions were VMC and I was obviously on an IFR plan.

- At what point do I know that it is ATC's responibility to provide separation (understanding that a visual lookout should be carried out always)? I assumed because I was on a SID i was protected. Must I listen for the word "identified". Do some fields provide separation from the minute you leave the ground?

- By saying that i had the traffic in sight, did I take responsibility? It was not a "with traffic in sight cleared take-off"scenario.

- If it had been IMC would the traffic have been allowed to route through the zone only 100ft bellow the SID?

- Lastly, how do you know whether the controller on tower and approach frequencies has radar or not?

Your answers will help a great deal, thanks.

[Foxy Loxy]

Some of those questions may be answered here:
http://www.pprune.org/forums/showthread.php?t=327783

Basically, there is no requirement for IFR and VFR traffic to be separated. Traffic info should be passed.

If it had been IMC would the traffic have been allowed to route through the zone only 100ft bellow the SID?
Assuming the traffic was being worked by the same unit, no. IFR separations will apply.

Lastly, how do you know whether the controller on tower and approach frequencies has radar or not?
Tower may have an Aerodrome Traffic monitor (ATM) but are not permitted to use it in the same manner as a radar controller uses radar. (That sounds a bit wishy-washy, sorry. Can't remember the rules off the top of my head)
To answer this point, the clue is in the aerodrome callsign, ie Tower (obvious), Approach (procedural, no radar), Radar (again, self explanatory.)
Whether this is failsafe, I can't be certain. I speak from my own experience only.

I'm sure there are more learned types who can go into more detail than I have here.

Foxy

[Spitoon]

You don't fly with littco do you?

See this thread for a lot of the answer. (http://www.pprune.org/forums/showthread.php?t=327783)

In theory you'll know whether the controller has radar from the AIP and the callsign used. Even though the tower controller may have a radar picture in front of him/her, it can usually only be used for very limited things.

[Skyjuggler]

Okay, I'll have a go here to answer, this however is in terms of our laws south of the equator.

There are a number of times that an ATC may be permitted to reduce separation in the "vicinity of an aerodrome", one of the provisors is that both acft have each other in sight, another is if the second acft has the first in sight (and will thus be able to maintain his own separation). I'm not sure which will apply to you more closely. However, having said that it's a little impracticle for the ATC to expect you to maintain your own separation while flying the SID. Of course I don't know the whole story and situation as it happened but from what you've said I feel the ATC may have had a small lapse in judgement.

Once again though, can't point fingers since I don't know the WHOLE scenario.

Hope it helps...

[Grum]

I was flying with littco. How about that, I should have read through the other threads. Hope he didn't blame it all on the captain:uhoh:

Thanks for the replies.

[HEATHROW DIRECTOR]

<<There are a number of times that an ATC may be permitted to reduce separation in the "vicinity of an aerodrome", one of the provisors is that both acft have each other in sight, another is if the second acft has the first in sight (and will thus be able to maintain his own separation). >

AND - very importantly (and the first proviso in MATS pt 1) - "a) adequate separation can be provided by the aerodrome controller when each aircraft is continuously visible to this controller".

In this respect, there could be no requirement for either pilot to be informed of the other aircraft and it is not required for the pilots to have the other aircraft in sight. Eg Overflying a/c passing over threshold of runway at 90 degrees to the runway at, say, 2000 ft... departing a/c climbing out on runway heading to any altitude. These two are not traffic to each other, even if they are IFR, if they can be clearly seen by the controller.

[Dizzee Rascal]

Can we merge these two threads as they are obviously the same.

In the mean time Grum and littco, I would strongly recommend you both visit ATC at the airport we are discussing, or any other airport in the UK OCAS with a procedural ATSU. Pay special attention when the ATCOs are explaining when they provide separation.

PS. They are not SIDs!

[HEATHROW DIRECTOR]

Dizzee.. Agree with what you say. When I worked at Kidlington back in 1971 we had "SIDs" for the IFR training aircraft which they used to join airways. OK, they were only promulgated amongst Kidlington staff but if a visiting pilot had heard ATC clearing someone for an "Enstone SID" (or whatever we called it) he might have been drawn to the wrong conclusion.

[radar head]

The minimum separation required by an IFR flight is standard IFR separation. When a flight is IFR then ATC is responsible for separating this flight from any others. Vertical separation is the simplest and most reliable separation to establish. The VFR aircraft should not be cleared to climb to a level unless the preceeding IFR traffic has reported to be at least 1000ft or 300 meters above that level.Then you will always have your 1000ft vertical no matter what the relative rates of climb are.

[Chilli Monster]

The VFR aircraft should not be cleared to climb to a level unless the preceeding IFR traffic has reported to be at least 1000ft or 300meters above that level.

What Mickey Mouse school gave you an ATC licence?

Class 'B' & 'C' - you can climb the VFR to the level the IFR previously occupied when you know the level has been vacated - either by report or by 400ft on mode 'C'

Class 'D' - 'G' Which part of "You don't separate VFR from IFR" do you not understand?

[terrain safe]

The minimum separation required by an IFR flight is standard IFR separation

Only from terrain (see my moniker) not from another aircraft. There is no such thing as standard IFR separation, only the required separation between aircraft based on the airspace they are in, the service being provided and the flight rules the aircraft is flying under.

[BaldEd]

Just to muddy the waters a little from way down here south of the equator.

Most small airports in NZ that are situated either laterally or vertically clear from controlled airspace have SIDs. These SIDs do not provide any separation from VFR or even any IFR traffic operating in that uncontrolled airspace. IFR traffic will be given traffic information on all other IFR traffic but not necessarily on any VFR traffic (the airfield may be out of radar coverage - most are - and the VFR aircraft won't be on any of the radar or procedural controller's frequencies).

The SIDs have been established to provide safe climbout routes that are clear of terrain obstacles and will position the aircraft so that it may intercept it's cleared route and controlled entry into controlled airspace. It behoves all pilots operating in the vicinity of these uncontrolled airports to communicate and coordinate their movements.

At controlled airports (CTR/C or CRT/D airspace designation) with CTA/C or CTA/D airspace above, the SID issued, in addition to providing climbout terrain clearance, may also provide positive separation from IFR and VFR traffic. The amount of positive separation though depends on the airspace designation. Radar may or may not be available.

Tower controllers throughout NZ have radar screens but they are limited in what they can do with it - it is just a tool that enables them to see approaching and local traffic that is within radar coverage (not all radar coverage is to ground level). Most tower controllers are not approach controllers as this function is done, in the main, from one central air traffic control centre that is in some cases many hundreds of miles from the actual airfield.

[Grum]

I do apologise for starting a second identical thread. Happy to have it merged.

I've read twice now that we were not flying a SID, but rather a SDR. Surely this standard departure route becomes a SID once you enter A,B or C airspace. To confuse the issue further, the Jepesson plate clearly states 'SID'.

[chevvron]

In the UK civil traffic world, you can only have a SID inside regulated airspace. Outside regulated airspace you get SDR's which do NOT clear you to enter controlled airspace, ( and are not assessed for obstacle clearance) but take you in the correct direction.
In the military world there are SIDs in class G airspace, but once again they do NOT clear you to enter controlled airspace, nor are they (like SDRs) designed to separate you from other traffic. Unlike SDRs they ARE assessed for obstacle clearance

[bookworm]

At what point do I know that it is ATC's responibility to provide separation (understanding that a visual lookout should be carried out always)?

The literal answer to your question is "when you check the class of airspace in which you will be flying". In class A, B or C airspace, you will be separated from VFR traffic. In class D, E, F or G you may not be, though UK ATC tends to do its very best pro-actively to assist in conflict avoidance in class D, even though there's no guarantee.

You were flying in class G airspace, therefore there was absolutely no guarantee of separation.

I've read twice now that we were not flying a SID, but rather a SDR. Surely this standard departure route becomes a SID once you enter A,B or C airspace. To confuse the issue further, the Jepesson plate clearly states 'SID'.

The reason your clearance was limited to 2400 ft was that the class A airspace starts at 2500 ft. I can't speak for Biggin, but at Cambridge where the situation is similar, clearance to enter class A or D is often only given after the aircraft is talking to and identified by TC (either Essex Radar or Stansted Director in my case).

[bookworm]

The AIP entry says...

Dizzee

Since many users, including apparently Jeppesen, don't seem to appreciate the difference between an SDR and a SID, how about getting them to insert a note pointing out the limitations of the SDR compared with a SID (uncontrolled airspace below 2500 ft, no promises regarding obstacle clearance)?

[Dizzee Rascal]

Since many users, including apparently Jeppesen, don't seem to appreciate the difference between an SDR and a SID, how about getting them to insert a note pointing out the limitations of the SDR compared with a SID (uncontrolled airspace below 2500 ft, no promises regarding obstacle clearance)?

I shall certainly make the suggestion to the powers that be, however, I suspect the reply to be something along the lines of "if it ain't broke why fix it" and "it's up to the pilots to know the difference" which are fairly appropriate answers!

Has anyone got a copy of the relevant Jeppesen charts they can send me?

[Big Hilly]

PM me your email address and I'll do so but it won't be until next week now, so maybe someone else can send them in the meantime?

Regards,
BH

[chevvron]

I've been trying for years to convince Jeppesen that a SID is not the same as an SDR as we have a similar problem; they're supposed to have 'fixed' the problem on their charts but they won't send me a copy to verify it; they insist they can only supply a 'full set' if IFR plates costing over £500!

[radarman]

Getting back to the thread title of VFR vs IFR. I have never been happy with the practice of providing traffic information and then sitting back assuming all will be well. At the end of the day, you could well have several tons of aluminium hurtling towards each other at a closing speed of 3 - 400 kts. Can any of the ATC posters to this thread put their hand on their heart and say this situation is OK because I've told them about each other and that's all the book says I have to do? What is the recommended procedure if the VFR guy says he can't see the IFR? Pictures of that PSA 727 going down in flames a few years ago in California haunt me to this day when I have VFR against IFR.

[mm_flynn]

What is the recommended procedure if the VFR guy says he can't see the IFR? Pictures of that PSA 727 going down in flames a few years ago in California haunt me to this day when I have VFR against IFR.A few years ago? That was 1978 and from a quick look it was the IFR guy who lost track of the VFR guy, didn't let ATC know and then hit the VFR from behind. (There seem to be a number of other factors in addition).

[Barnaby the Bear]

Apart from introducing CAS everywhere its not going to get much easier especially in an environment such as Biggin with limited vertical airspace to play with.
It would help if 'some' of the VFR pilots looked out of the window a bit more instead of at their TCAS and GPS. :ugh:
As for the original post, ATC has provided you with the traffic. If you are not happy request to wait a little longer until it has left the area.
I am sure the majority of ATCO's will give as much assistance to help look for the aircraft or suggest a level more comfortable. But being VFR they may not be able to accept it... or want to (outside CAS).

[chevvron]

One problem with Biggin is the fact there is a lovely big VOR on the airfield which attracts transit traffic. Everyone routing south of the Heathrow CTR wants to use it in spite of our cajoling not to.

[mm_flynn]

which is the lesser problem for you guys, 2000 ft overhead or 1500-2000 3-5 miles to the South? Or is there a better option?

[ATCO Two]

The other complication with Biggin is that it has an elevation of nearly 600ft, so 2000ft will be well within the ATZ, and will conflict with circuit traffic. Alternative options are 2400ft through the overhead, subject a clearance from EGKB ATC, or 3nm or so to the South. Perhaps the easiest route for VFR is to follow the M25, which will take you clear of Biggin and the EGKK CTA.

[chevvron]

ATCO Two: follow the M25 is precisely what we suggest to them but many pilots don't seem willling to do that; they've flight planned via BIG and they're gonna go that way even if it does restrict Biggin and create extra workload for their ATC.

[Del Prado]

they've flight planned via BIG and they're gonna go that way even if it does restrict Biggin and create extra workload for their ATC.

surely a 10 minute delay before onward clearance can be issued would encourage some of them to find a 'better' route?

[airac]

Biggin is 600' AMSL base of CAS is 2.5 therefore only 1900' to play with. Since ATZ is 2000' AAl ,ATZ is 2.5 nm The instruction to remain clear/outside ATZ, would/ should stop A/C flying through the overhead.
The real crux of the problem is that many pilots do not understand that at 2.4they are still in the ATZ .
Worse still, are the few pilots and I stress very few pilots who actually take up their right to fly in class G airspace without talking to anyone and as such do not fully plan their route with the use of VFR maps. GPS has helped a great deal but in the wrong hands??
This is NOT anti pilot either.

[Spitoon]

surely a 10 minute delay before onward clearance can be issued would encourage some of them to find a 'better' route?Sorry, but this is not the way to do ATC!