Approach Procedural Control

[parkfell]

Here we are, established on the ILS at 8 miles, with one line lined up for departure.

ATC [APC/ADC combined] say that they cannot launch the IFR outbound until they get me in sight. [reduced separation in the vicinity of the aerodrome] Due to a low cloud base, I do not become visible to the ATCO until 1.5d.

The outbound is now cleared for immediate take-off, and I receive landing clearance at under 300ft. I had reduced to min approach speed at 4 miles.

Question:

If I am establised at 8 miles why cannot the outbound launch?

Where exactly am I meant to go in the event of a missed approach, with one departing ahead less than 2 miles away, and shortly going IMC??

Is this a MATS Part One requirement, or could a MATS Part Two instruction resolve this issue?
:confused:

[AlanM]

Well - it depends where you are.

Give us a clue fella!

[Spitoon]

Also depends rather on where the outbound can or must go. More info will help but in some circumstances it may just be impossible to find a separation that can be used.

[peatair]

Back in the 1960s at EGPH we had this issue. The Unit then operated procedurally. As I recall, the practice was that once an aircraft reported established inbound then no outbound could depart unless / until the inbound was either visual with the outbound or the ATCO could see both aircraft. In those days ILS did not have DME - only an outer marker.

Why cannot the accuracy of a DME report be accepted and if you have (say) 5 miles or more when the outbound commences roll you ought to be safe???? Seems to me to be a damn sight safer than the scenario of allowing the inbound to get ever closer and then clearing the outbound for take-off at the last minute.

Seems to me that you guys need a chat with SRG and get this sorted !!!

[HEATHROW DIRECTOR]

If the position of the inbound can be determined accurately then surely geographical separation can be applied? There should be something in the local Part 2 stating that departures may be cleared for take off up to the time the inbound has passed the OM.

[Loki]

From what I can remember of procedural approach work (a very long time ago) that seems ridiculously restrictive....but without the full details it would be foolish to be too definite.

[055166k]

Awful situation, you play it by the book and very little moves. Procedural control is the highest ATC discipline, often laughed at by colleagues at a radar-equipped mega-jetport. It requires a controller to have a large bag of tricks, unlike sausage machine controlling, and to be able to apply different elements of procedural separation in differing and changing circumstances, perhaps determined by available nav-aids.
I don't know the circmstances but I would not have lined one up from what you say.
If the outbound was IFR then visual sep would not work with such poor vis and cloudbase because the outbound would almost immediately be lost from view, however I can think of two or three procedural get-outs if you had gone-around....but I would need to know the exact airport and runway to devise a cunning plan!

[AlanM]

It sounds like something that happens at Biggin Hill daily.....

Due to it's proximity with the Gatwick Zone - all IFR airways departures have to go to Detling. This means that the aircraft turns right after take off from runway 21 to do a 240ish degree turn climbing to altitude 2400ft in the overhead before setting course to Detling (essentially due East from Biggin, elev 600ft)

Now, when there is an inbound, the departure can be released if the inbound is outside 10nm and 160kts or less.

If the outbound is on a slot, and has the priority, we can hold an inbound off.

Otherwise, the controller can await until the inbound is visual and then safely launch the outbound. At Biggin they only tend to do this when the weather is suitable, with the outbound rolling when the inbound is at 3 to 5 miles.

So - if it wasn't at Biggin, maybe they too have an outbound SDR that is not separated from the inbound track!

Is a late landing clearance that much of a problem? Or were you below decision height?

Either way - thank heavens for Mode A/C on my screen!:)

[vintage ATCO]

What is required here are some deemed separations in Section 2 of the MATS Pt 2. Someone needs to look at it, decide what's achievable, write it up and have it approved.

But then, p'raps they have and it isn't :D

Depends on the outbound routes of course.

[Sky Conductor]

Depending on Airport nav aids, airspace dimensions and Aviation Authority approval there are a number of "tools" which can be used to "see" a departure through an arrival..it depends on the location of the inbound when the departure is ready to go. In the above mentioned senario a separation commonly used in Irish regional airports is the "45 degree sector". Which at 8 dme on the ILS he would probably have been in depending on that airports cut off fix, which may be 5 or 6 dme on the ILS. So once the arrival is outside the this fix when the departure gets airbourne it is fine..but the departure must make good a magnetic track which keeps him outside the 45 degrees of the reciprocal of the inbound track until vertical separation can be established ..ie 1000ft above the missed approach altitude...confused?? take for example inbound a/c loc estb 8 dme on ILS rwy 36..departure instructions for dep a/c routing north BAW2X3..after departure turn right track 315degrees magnetic climb FL210. This keeps dep 45 degrees away from arrival until vertical achived. Normally after the inbound cut off fix the controller would get the inbound visual and separtion in the viscinity of the aerodrome can be used. In the above case in poor wx the departure does not start rolling after the inbound has passed the cut off fix...well then your up s@$t creek!! Love a radar controller sit in on that..and watch is face turn!!

[AyrTC]

Hello Mr Parkfell,as I think I know who you are:eek: I would presume it was at a H&I airfield.Its about 15 years when I last did
pure APC so I may be a bit rusty.

APC is a slow system and you would be surprised how very few deemers these airfields have.Since I left EGP* I know some sort of deemed speration was brought in ,however that was to do with deps/ against arc procs.

Of course if the aerodrome :D in question has only recently installed an ILS (luxury lad all I had was a black pen,a bit of paper
and a packet of chocolate biscuits!! ) it may take some time to try and get the nod from SRG.

I would think the main hurdle would be the go around.If you overshoot in a fast ship ie a Saab 340 and the TWR/APC controller has just launched an Islander with a 25 kt headwind there is no place to go especially if there is high ground in the vicinity " Hoy!! watch out for that hill."

On several ocassions I had told "Budgies" specific creative instructions and when the pilot comes back and informs you that it will be o.k as long as he does not have an engine failure after t/o it does tend to worry you to try anything flash.Procedural is a slow system and I now have to keep telling trainees this when they come and train on the old "North Scottish":\

AyrTC

[HEATHROW DIRECTOR]

<<Procedural control is the highest ATC discipline, often laughed at by colleagues at a radar-equipped mega-jetport.>>

Couldn't agree more. I cut my teeth on Procedural Approach and Area Control and it was great fun. Taught me things I still used right up to my retirement..

[ProcATCO]

Speaking as one who has never done ADR, this is a judgement call by the controller.

If the conditions are below the airport's Low Vis Procedures, the outbound should not even have been given line up clearance.

The onus is on the controller to ensure that that safety is not compromised in any way shape or form. However, I reiterate THIS IS A JUDGEMENT CALL depending on the conditions (traffic, weather etc.) at the time.

There are a large variety of ways that the competent APC controller can resolve a situation like this - it depends on "deemers" and the knowledge and confidence of the controller.

Don't worry pilots - we will look after you to the best of our skills!!!!!





:ok: :ok: :ok:

[HEATHROW DIRECTOR]

<<If the conditions are below the airport's Low Vis Procedures, the outbound should not even have been given line up clearance.>>

Perhaps not under the procedures which appear to exist at the airfield in question, but at a busy airfield with full facilities single runway operations in LVPs are perfectly safe. Final approach spacing of around 10nm usually suffices with a departure in each gap - ask my colleagues at Gatwick, where they can really shift some traffic on one runway.