"rule of thumb" in procedural control

[ericliu]

In procedural control, the controller must have the ability to calculate the estimated times of passing of two a/c (or more) each on a reciprocal track, so could anybody give me some "rule of thumb" on how to do it rapidly, especially for the aircraft with different speeds?
Many thanks!

[Beside myself]

It's been a LOOONG time since I did any procedural but if I'm not mistaken, it's a quick equation.

Get both aircrafts estimate for a common point, find the average and presto, should be an approximate crossing time.

eg.
ACFT1 est DUMBO at 1630
ACFT2 est DUMBO at 1638 Both ACFT on reciprocal tracks

Their crossing time should be about 1634.
But that's with acft with similar speeds, but a good starting point...

[Take up the Hold]

And using the example of 'Beside myself' aircraft had to have crossed levels, if climbing or descending, 10 minutes before the pass, so vertical had to be achieved by time 24. Of course separation can be closer when using a VOR or NDB for separation.

TUTH

[TheFalcon]

Ask them if they see each other and to report clear. Thats the easiest

[DFC]

To do this you have to do two things, 1 establish the distance between the aircraft and then establish the closing speed.

Beside myself assumes that the flights are travelling at the same speed.

Here is an example that I hope I can explain without a drawing ( and my math is correct);

Airway segment - AAA to BBB. 360nm long

Aircraft 1 passes AAA at 1000 and estimates BBB at 1100

Aircraft 2 passes BBB at 1010 and estimates AAA at 1055

When will they pass?

1. Ask yourself where Aircraft 1 is when aircraft 2 passes BBB

Answer = 10 min after AAA.

2. With the estimates and known segment length you can work out using groundspeed how far Aircraft 1 has travelled in 10 minutes - 60nm in this example.

So when Aircraft 2 passes BBB, Aircraft 1 is 60nm past AAA or more importantly Aircraft 1 is (360-60)= 300nm from BBB

Thus at 1010 the aircraft are 300nm appart.

Based on estimates and segment length, Aircraft 1 has a groundspeed of 360Kt (6nm per minute) and Aircraft 2 has a groundspeed of 480Kt (8nm per minute).

Their closing speed is thus 14nm per minute.

At that closing speed and that distance appart they will cross inbetween 21 and 22 minutes (mental rather than calculator).

That means that the pass happens between 1031 and 1032.

Using 10 minutes before and after the estimated pass, gives you 1021 to 1042.

-----------

You can crosscheck your calculations by asking yourself where each aircraft is at 1031

Aircraft 1 will be 31*6 = 186nm past AAA

Aircraft 2 will be 21*8 = 168nm past BBB.....which is 192 from AAA.

At 1031 the aircraft are 6nm appart closing at 14nm per minute!

--------------

To sumarise, check where the first aircraft to enter the segment is when the second one enters and this gives you the distance appart. Use the estimates and known segment length to calculate the closing speed.

The distance the aircraft are appart when the second one enters the segment divided by the closing speed is the time to cross.

-------------

You can use a similar for overtake.

----------

The above allows for different ground speeds of the aircraft and uses the info available from the FPS

Regards,

DFC

[Talkdownman]

Not a lot of use, but back in the sixties we used to use a particular formula to determine when the separation had to commence and cease, but I am damned if I can remember it. Something involving T1 plus T2 over the difference in speed etc etc. I wish someone could remind me. I doubt if Bert Spalton and Lew Parton who taught it me are still around....Ho Hum..
anyway, it usually got spoilt by some radar controller or other interjecting on the intercom whilst looking at his AR14 or 232....

[BaldEd]

When faced with opposite direction aircraft of similar speed. Find the time difference between the 2 aircraft at a rep pt and add half that time to the first aircraft to cross that point. They will cross at about that time - this of course depends on them giving you accurate estimates in the first place.

When faced with opposite direction aircraft of different speeds. Find the time difference between the 2 aircraft at a rep pt. If the faster aircraft crosses the rep pt first then the pass will occur prior to 1/2 the time difference. If the slower crosses the rep pt first then the pass will occur after 1/2 the time difference. The amount you need to subtract or add can be roughly estimated (rule of thumb) and will depend on the difference in times of both aircraft crossing the rep pt. e.g. if the time difference at the rep pt is 15 mins and the faster crosses first, then the pass will occur probably 6 mins after the first has crossed the rep pt. Give the pilots warning of the ETP and ask them to look out. At 6 mins if they have not sighted each other then ask each for his DME distance from the rep pt. You can be sure that they will be fairly close to each other. If they have already passed by 10 miles you are sweet to change levels. :)

There are exact formulae for these cases but I found from experience that using the rule of thumb above and comparing the result with the prayer wheel' s (circular slide rule) answer that they usually agreed.

[Late Landing]

Difficult to explain - easy to do.

Theory:
Acft A crosses XX at (time), Acft B Est for XX is (time), Calculate the difference in minutes at XX.
Now use the formula {Speed of SLOWER Acft divided by (Speed A + B)} and apply this formula to the differnce in time for XX. This will give the time for the FASTER aircraft to/from XX.

Practical:
Acft A speed 250kt crosses xx at 15, Acft B speed 125kt Est xx at 30.
Diffence in time is 15 minutes
Formula {125 divided by (125 + 250)} equals 1/3.
Apply this to the time difference of 15 minutes, gives 5 minutes.
Apply to the faster aircraft and at time 20 Acft A will cross Acft B.

Obviously to confirm the passing time you can apply the 'reverse' formula using the Speed of the FASTER Acft and apply it to the SLOWER Acft Est for XX.

[scran]

Using DFC's example,

Set a base time (in this case 1000) and add the 4 time intervals:

00 1 over AAA
60 1 over BBB (60 minutes after the base time)
10 2 over BBB
55 2 over AAA

Add them: 125

Divide by 4 = 31.25

so Estimated Time of Passing is (rounded up) 1032........................:ok:

Gives a quick approximation - thats ehat I was taught back in 1976......:eek:

[zkjaws]

There is a simple formula to work out the Estimated Time of Passing (ETP)

ETP = ETO1 + EET1 (ETO2 - ETO1)
EET1 + EET2
EET = Estimated Elapse Time between two points
ETO = Estimated Time Over one point

It can be found on a pray wheel (nav computer) by:
Set EET1 + EET2 on the outer scale over EET1 on the inner scale;
Opposite ETO2 - ETO1 on the outer scale read X on the inner scale
Add X to ETO1 = ETP

[dsham]

In OZ unfortunately we still very much do procedural control..... luckily though we have the "Time of passing tool". Click on the first aircraft, press the TOP button, click on the second aircraft.... whallah! TOP..... we still have to learn the old way though, in case you spill coffee on the keyboard or something.

[ericliu]

dsham：
Could you say more about the "Time of passing tool" ? Where do you click the aircraft? Do you have radar display under procedural control?

[callum91]

I am intrigued by procedural control and the CAP493 guidelines are too vague for my understanding.

When aircraft are being held in flight, the appropriate vertical separation shall be provided between holding and en-route aircraft while such en-route aircraft are within 5 minutes flying time of the holding aircraft’s flight path.


Does the above apply if you have an IFR departure and an IFR arrival (the arrival holding overhead the airfield)?

If not, what is the required separation and what does it depend on? (i.e. if the arrival is already holding when the departure takes off or what if the arrival is still on the inbound track and also does this depend on what direction they are going).

[dsham]

We have a Eurocat system - so all tracks are displayed (ADSB/ADSC/RADAR/PROCEDURAL), it is an interactive system whereby each aircraft has a label and a track designator. You just click on the label (this designates that aircraft) press the TOP button on the keyboard, then click on the label of the other aircraft - and the Flight Data Processor does the rest....

If you want to know more google - TAATS or THALES Eurocat and im sure you'll find something

[Hyperborean]

Callum91, the simple answer is yes. Inbound holds at suitable level and outbound climbs to 1000' below until the 5 minutes is achieved. In practice one would find an alternative separation to improve expedition. Unless you've got a stack when procedural separation becomes very intriguing, which is why I enjoyed it. With just 2 aircraft track separation against the approach procedure is easiest but the joy of procedural is that if you give a problem to 2 controllers they will provide you with 3 solutions ( all perfectly valid).

[callum91]

Hyperborean - Thanks for clarifying that for me - I always thought it was 5 minutes! :)

[e195-001]

Hi everyone
I'm really sorry for bringing up such an old thread but just wanted to say Bert Spalton is still about and doing well.

I am David, his grandson, never fully followed the family business but do weight and balance at LHR so almost.

I will pass on regards to Bert

Dave

[2 sheds]

Dave

See PMs.

2 s

[Talkdownman]

Dave,

Very, very pleased to hear that Bert is still around!
That man just cracked me up on the area procedural course (Jan 1970) when he would go outside and collect moss and algae and return to decorate the students' 'dead wood'...He and Paddy Holt made learning a pleasure. But I still can't remember that formula. Maybe Bert will remember...

[ZOOKER]

Dave,
Great to hear that. I worked with Bert from 1979 to his retirement at an airfield not far away. He was D Watch supervisor.
I first heard about him in about 1970, at Loughborough College where his nephew, Gerry Spalton, taught me 'O' level chemistry.
ATC is a small world!

[e195-001]

Hi guys
It's lovely to hear the old stories about my grandpa, if you have any more please do share them and I will print them out and take them next time I visit.

Dave

[Brian 48nav]

Malcy,

In simple terms it's __Ground speed A/c A over Ground speed A added to Ground speed A/c B. Very similar to the Critical Point formula for finding when the destination airfield is closer 'timewise' than airfield of departure etc.

[HEATHROW DIRECTOR]

Bert was at Heathrow 1969-76. I worked with him from 72 until he left. Can I stop taking the tablets yet? Please pass him my best.

Brendan McCartney

[kcockayne]

I did procedural at Shanwick Oceanic whilst on my Cadet course. As far as I remember there was no complicated formula or need to take into account different speeds on reciprocal traffic.
Put simply, if one aircraft Eastbound estimated 55N 20W at 1210 & the reciprocal Westbound estimated it at 1230, then the aircraft crossed at 1220.
It doesn't matter whether the aircraft have different speeds, they are still going to cross at the same time (AFTER the Eastbound has passed the waypoint & BEFORE the Westbound has passed it). Even if one was only doing 100 kts & the other 500 kts, the crossing time would be the same.
It is immaterial that the aircraft have different speeds - that ONLY effects WHERE the aircraft cross NOT the time that they cross.
Using this, vertical separation must be established 10 minutes before (or after) this time.

[2 sheds]

It doesn't matter whether the aircraft have different speeds,

WHAT........!?

[BaldEd]

:eek: I'm with you 2 sheds.

[off watch]

Am I missing something here ?
If the eastbound aircraft is doing 6 miles per minute. at 1220 , it will be 60 miles east of 20W. If the westbound is doing 2 miles per minute, at 1220 it will be 20 miles east of 20W so by my reckoning they would have passed at about 1215 !

[topdrop]

Hope they are not doing procedural in Jersey/

[kpnagidi]

I am intrigued by procedural control and the CAP493 guidelines are too vague for my understanding.

When aircraft are being held in flight, the appropriate vertical separation shall be provided between holding and en-route aircraft while such en-route aircraft are within 5 minutes flying time of the holding aircraft’s flight path.

Does the above apply if you have an IFR departure and an IFR arrival (the arrival holding overhead the airfield)?

If not, what is the required separation and what does it depend on? (i.e. if the arrival is already holding when the departure takes off or what if the arrival is still on the inbound track and also does this depend on what direction they are going).

Caught it a little late... but here it goes. IF the holding's inbound track is opposite to the track of the outbound aircraft, have the acft in hold report to you when established inbound leg, ask for dme and then ask outbound acft's position in dme. If they have the 10dme tail to tail, you're good.:ok:

[Lon More]

Not quite up to going out for moss, but remember the late Bob Cheyne plucking a strip from the display and scrutinising it very closely. "I'm looking for roots."

[chevvron]

My old mentor at Lindholme, Les Coyle, once told me a good one.
2 aircraft northbound on Amber 1 (yes it's that old).
Aircraft A, a DC3, crosses POL 10 min ahead of Aircraft B, a DC4 = separated.
Aircraft B estimates crossing DCS 7 min ahead of Aircraft A = separated.
The 'D' man took a while to twig what happened when the DC4 asked permission to overtake the DC3 on the right!

Sorry got my VOR's mixed up; thanks Lon

[Lon More]

Especially as POL is south of DCS :\

I remember phoning Preston to complain about not getting 6-7 minute time revisions, and being told, "You're :mad:ing lucky! We work with :mad:ing London. We don't get :mad:ing estimates!"

[kcockayne]

Off Watch,

I agree with your maths.

Perhaps my illustration was mathematically half baked & didn't serve to explain my point correctly.

What you said was basically what I was trying to get across.

It is the time that the aircraft cross when on reciprocal tracks that matters & speeds are irrelevant. ie A/C A estimates point X at 1010, A/C B estimates point X at 1020; result:- aircraft cross (on reciprocal TRs) at 1015 - when A has passed X & B is yet to get to X (the actual distances of either a/c from X being determined by their speeds)..

Speed differential simply accounts for the a/c crossing point to be further away (Or closer to) point X.

[2 sheds]

kc

With respect, what you are saying could still be somewhat misleading.

It is the time that the aircraft cross when on reciprocal tracks that matters & speeds are irrelevant.
But it is the speeds (groundspeeds) that determine the time - and position - at which the cross will occur or will have occurred.
A/C A estimates point X at 1010, A/C B estimates point X at 1020; result:- aircraft cross (on reciprocal TRs) at 1015
But only if they happen to have the same groundspeed!
Speed differential simply accounts for the a/c crossing point to be further away (Or closer to) point X.
...in both time and distance. "Simply..."? - it is this calculation that requires the mathematical dexterity and understanding - and an accurate knowledge of the groundspeeds.

Regards

2 s

[Howabout]

I'd offer the following, but it's been a long, long time:

In the procedural environment, one is fixated with 'fixes.' I think the argument concerning only one fix is misleading. Aircraft, in a non-radar environment, should be tracking from fix to fix. They report at one (definite), with an estimate for the next (calculated on ground speed).

For reciprocal tracks, any speed differential is irrelevant. Estimated time of passing is a calculation based on a definite report and an estimate based on the known.

Hammer me if you must, but the single fix argument clouds the issue. In procedural, 'fix to fix' is essential to safe separation - no ifs, no buts. Procedural is all about 'fixes.'

This is pretty simple:

Aircraft A reports at OBAMA at 0136 estimating DUBYA at 0215

Aircraft B reports at DUBYA at 0146 estimating OBAMA at 0219

Once again this is (essential) fix-to-fix stuff in a procedural environment.

Take the base-hour (0100) and do the following:

Aircraft A = 36+75 (the 75 is the extra 60 on the base-hour plus the 15)

Aircraft B = 46+79 (see foregoing)

Add the times up - 36+75+46+79 = 236

Divide by 4 = 59

Add to the base-hour of 0100 and ETP is 0159, then apply the 10 minutes (before/after) for level change.

[2 sheds]

Howabout

My only dispute is that it is misleading to say that "any speed differential is irrelevant". I think that would be better expressed as "any speed differential is already built in" - as you are factoring the different elapsed times over the same distance.

A single fix calculation does not cloud the argument at all - it all depends how distant or imminent (reliable) the information is. Given knowledge of the groundspeeds, you would deduce the same answer from either of your pairs of ATO/ETO.

Cheers

2 s

[topdrop]

Howabout,
Your fix to fix works - it includes speed (known distance taking a certain time). Using the speeds between those fixes, using either waypoint in the calculation, also works.

Using your example:
Assume distance between fixes is 250NM – use any distance you like.
Acft A speed = 250/39*60=385KT
Acft B speed =250/33*60=455KT
Difference in time at OBAMA=43 mins
Speed slower/(speed A + speed B)* Time Differential at fix. Apply this to the time of the faster acft gives ETP. It is either added or subtracted depending on whether the waypoint you used has been passed or yet to be passed
385/(385+455)*43=19.7mins. Subtract from Bs est for OBAMA = 0159.
Using DUBYA as fix: Difference in time is 29 mins.

385/(385+455)*29=13.2mins. Add to B’s time over DUBYA=0159


Both methods give the same time.
The best thing about the grouondspeed method is that the calculation can be used between acft on tracks up to 45° apart as long as they have a common waypoint.

[kcockayne]

2 Sheds

I take your point. Injudicious wording on my part.

Thanks for your input.

[2 sheds]

kc

No worries!

2 s

[Andy Mayes]

Blimey, I'm glad I don't do much procedural because I've completely lost the plot with this thread.

[2 sheds]

Andy, the saving grace is that most of this is just not required now - at least in our part of the globe. Interesting though that the odd snippet that might still apply got through without comment...
Aircraft A, a DC3, crosses POL 10 min ahead of Aircraft B, a DC4 = separated.

2 s ;)

[HEATHROW DIRECTOR]

Andy.... you're not the only one. I did procedural abroad for nearly three years and it was a lot easier than one might imagine from reading this.

[Howabout]

topdrop,

Thanks. That all makes sense. I used to enjoy the 'black art.'

HD, as regards easy, I'll riddle you this one. And no disrespect - you obviously mastered APP when Moses still hadn't checked out on SMC, or whatever 'ground' is called over your way.

Two aircraft:

Aircraft A is a BE200 inbound to destination from the boonies and tracking west to east from an NDB at FL200 - the track-length is huge (300nm) and there's nothing else out there for IFR nav; no DME at departure point and too far away for a signal from the destination. We are running on estimates only and the next estimate is abeam an NDB 50 minutes away. The track is close enough to a dead-set 090/270 west to east.

Aircraft B is a military jet on the ground with UHF only and an ADF- disregard TACAN - no sites out that way. He is gas-challenged, had to land (planned) at this intermediate spot, and needs to get to FL 280 to reach his destination 450.nm away with the mandatory reserve. His track, SSW to NNE (say 200/020), will cut across that of the BE200 about 150nm from his departure point. There are no comms on the ground; he's 250nm away from Centre with UHF only and you are not going to have contact before departure plus 30 (or thereabouts) in the cruise.

He must get to FL280 or it's a no go. The only contact from the pilot of the jet is a phone-call on the ground prior to departure for clearance - you won't hear from him again till he's in the cruise. Your calculations tell you that there is a definite conflict and that you must have a standard to get the jet through the level of the BE200 - no radar, no comms and you can't hold him down.

What clearance do you issue on the phone to safely get him above the BE200 before crossing? He has a CLIAS of 220kts (military trainer) - apart from that, you've got zip, except for a good overhead map, a china-graph and the procedural 30deg 'spanner.' (protractor).

[Howabout]

Jeezus HD, I had to do that in real time and you've had four hours to think about it.

Yeah Andy, procedural is real easy.

[Brian 48nav]

Maybe I'm getting thicker than I used to be, but surely your question is a little bit vague.

Is the pilot of the jet ringing as the civvie is 300 miles away? What is his rate of climb? What speed is the civvie doing? etc.

If his ROC is say 3000'/min then after 7minutes he will be at 21000' and will have gone only about 32 miles (climb IAS of 220kts will be TAS of about 330kts above 25000' - so rough average TAS in the climb to 21000' is 270kts, 7 mins worth is about 32 miles) so well above the civvie by the time their tracks cross.

Reminds me of October 1st 1968 - we were in an RAF Herc' (XV206) flying from Rockhampton to Darwin at FL205, quadrantantal in those days IIRC in Oz, and in the back of beyond the Flt Eng yelled 'Christ that was close' and said a twin turbo had passed over us, right to left, by only a few feet!

Think I've had too much vino tonight, back to the homebrew bitter!

PS Are you in Darwin?

[Howabout]

Damn, I wrote a long dissertation on the solution, but the site dumped it before I could get posted. One of the infuriating things about this site. There was also an apology to HD.

HD:My apologies:there is no solution that conforms with SARPS. I cheated..

Flying Ballast: Great times with all you guys from transport and maritime. I am no longer in Darwin but have very fond memories of the RAF trash-haulers in Darwin and the fish-heads further south. You blokes could hold your grog!

[Andy Mayes]

Did we ever reach a conclusive answer to the original question?

I felt like a lost procedural cadet again with all the various equations I'd never heard of after the first page.:bored:

[HEATHROW DIRECTOR]

Don't worry Andy. I don't know what SARPS is.

[callum91]

ICAO Standards and Recommended Practices

[Howabout]

HD, once again my apologies - you were doing APP before Moses checked out on Ground. I fudged it. Didn't have a lot to go on.

I drew the tracks on the overhead map with the china-graph. In those days we had these amazing tools! - a straight-edged ruler calibrated to the overhead map, and our 'spanners, which allowed one to draw the tolerances on a planned track out to the max of 30nm either side of track.

Consequently, I took out the 12 deg spanner to work out the NDB tracking tolerance from the departure aids (NDBs) and projected that out to 30nm either side of track. I then worked out the worst case (least distance from the jet’s departure point) where the nav tolerances merged. All by the book. The problem, accurately plotted, was up there in black and ink.


This is where the problem arose. As the jet didn’t have DME and there were no other in-cockpit or relevant ground aids, I couldn’t give him a reach F210 x so many miles short of worst case intercept. All I had at this point was his CLIAS, so I bent the rules a little.

I knew from the ARFOR that there was virtually no wind out that way and, therefore, that his actual speed over the ground would be less than his CLIAS, which built in a fudge factor on the safe side.

Based on his CLIAS, I gave him ‘reach F210 by set-heading + so many minutes’ – to put him above the B200 10 minutes before the worst point of conflict.

There was nothing else out there in the boonies to base separation on. Yes, I cheated!


Even if the jet had sufficient gas for me to hold him down, there was no way to establish a standard when he was out the other side of the conflict zone. I didn’t identify him in the cruise until he was 30mins past the area of conflict because radar coverage 150nm from the head was non-existent below F290.

If anyone can come up with a better ‘solution’ in this a negligible-aid environment, with no comms and no radar, I’d like to know what it is!

Once again HD, my apols.

[HEATHROW DIRECTOR]

Howabout. No need to apologise - truly. When I did area procedural control there were devices of an extremely simple nature into which the ATCA fed in the upper winds (by writing them with a chinagraph) and by some sort of rotating gizmo various information could be obtained. These was used to calculate ATC estimates for various reporting points - often more accurate than pilots'!

Estimates for crossing times were worked by true rules of thumb, taught to me in a matter of minutes, but I cannot recall how they worked other than it was dead simple (it had to be as I failed O level maths dismally). When things were busy and aircraft were screaming for "higher" there wasn't time for long calculations. We used the above gadget and a bit of mental arithmetic. For traffic off normal routes I had a my own nav computer - spin wheel type, NOT Dalton computer! Using the upper winds provided by met this was all that was needed. Great fun and I really enjoyed it.

[topdrop]

Howabout,
Used to do procedural and did enjoy it. Draw up the nav tolerances for both acft - used to be 12° from the NDB to range of the NDB, then 15° (for DR) until you reached 30NM either side of track, then parallel 30NM either side of track. Gives you the basic lat sep points for entry and exit of the area of conflict. Work out how many mins after dep, the jet will be at that basic lat sep point distance and give him a requirement to be above by that time minus 5 minutes.

[Howabout]

HD & topdrop,

Sorry, I didn't want to appear as some smart-arse bugger that 'knows it all.' It was just an interesting problem and taught me that in the procedural environment there are situations that arise that really strain the brain. There are not necessarily 'rote solutions' to every situation.

However, that happens in all ATC environments. I am pretty sure that both of you have shaken your heads when a trainee has tried to solve a problem as though there was a template. Seen something similar before, so that's the universal fix.

As you both know, each situation is different (however marginally) and there's no 'universal fix' for any problem. That's what's so challenging and satisfying about the job - plus, not everybody has the warped brain to cope!

[Howabout]

HD,

Good grief, the old circular nav computer? Is it still used? I had my own and it was worth its weight in gold. Never went on shift without it. I used to call it my 'prayer wheel.'

When doing FLOW, it was ordinarily just a matter of getting the ground-speed readouts, checking distance-to-run to final and, with the aid of the prayer wheel, making a few speed changes to make it all fit before APP had to catch them.

Best fun I ever had, but it didn't always run to script!

[HEATHROW DIRECTOR]

<<I am pretty sure that both of you have shaken your heads when a trainee has tried to solve a problem as though there was a template.>

You mean like the bloke I had at Heathrow once who thought he could do GMC using PERT diagrams!

[Andy Mayes]

thought he could do GMC using PERT diagrams!

What is a PERT diagram when its at home?

[DaveReidUK]

What is a PERT diagram when its at home?Program Evaluation and Review Technique - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Program_Evaluation_and_Review_Technique)

Not to be confused with a PERT bum.

[Lon More]

But a pert bum begs for a PERT

[Howabout]

Good one LM! Are we still allowed a little bit of non-PC humour these days?? I've been out of it for a long time.

Notwithstanding, I really do worry about what I saw as a 'lack of creativity' before I left the scene - controllers that had a limited degree of flexibility and an unholy reliance on technology. Not their fault, just the way they'd been taught.

No doubt I am a dinosaur, but if the radar fails what's left? Sure, systems these days are far more reliable than they used to be. I shouldn't be concerned; I am out of it now and it's no business of mine. But I just wonder what happens when the system crashes, the track-prediction tools aren't available and one no longer has the Mode C or S readouts.

If you've ever been in a situation on APP, and I have a few times, where the picture suddenly shrinks and disappears up its own rear-end, you thank God you've got a good knowledge of the back-up. There's nothing else and I wonder if the skill is still being taught to the degree required.

I wasn't particularly proficient, but I could get by.

As the radar picture dies before your eyes, the brain is going 'sh*t, sh*t, sh*t. not again!'

[Brian 48nav]

Even more worrying to this dinosaur, would be to be pax on an aircraft where all the pretty pictures on the flight deck fail and the pilots are incompetent without them; think AF447.

I would want to be with the QF32 guys in a situation like that! At least if APC radar fails, TCAS will be your friend while you are applying WD40 to those old brain cells and searching for the bit that 'filed' procedural.

Thinking of pert bums, we had a lady on my watch at LL who was blessed with such ( or so we naughty boys thought)! One day she was doing Ground and recognised on the RT a former member of our watch who was now a driver with BM,'Hi Tiny' says she,'Hello nice bum' he replies.

Another day she was walking up the steep stairs into the old tower followed by a male ATCO from another watch. At the top he announces 'Nice a*se, shame it's on a girl!'.

HD, Window Job and Chevy will know who I mean.

[Howabout]

Brian 48nav, I did mean to acknowledge in a previous post the veracity of your calcs - red wine or not. They were pretty much on the money.

The limiter in the ATC world is that 'wouldn't hit in a fit' is not a valid standard. You might bloody well know that two aircraft are never going to come within miles of one another; but, but, you must have a verifiable standard that guarantees separation.

Sometimes, we may appear a bit anal to aircrew, but them's the rules we are bound to live by. If we don't, it's our d*cks on the block, not yours. Apart from the minor matter that in a really skinny one you might be involved in an aluminium shower

Enough, enough, Dear Ballast. I have just discovered a lovely Merlot that my wife thought she'd successfully hidden. Now, where's that blasted corkscrew?

[Brian 48nav]

Thank you for your kind words! I do find 'dear ballast' funny, particularly as I ceased to be a Herc' nav' late '73. Then I became a civilian ATCO for the rest of my career. Guess which is easier?

[Plazbot]

Procedural control is bad medicine. Most irritating years of my ATC life.

[Howabout]

Tobzalp,

You must have gone to a different school.

A day on procedural for me, particularly when the green-screen suddenly went t*ts-up, made me feel that I had earned the shilling.

[Plazbot]

Are you sure about that?

[Howabout]

Plazbot,

Pretty sure. Unless it was 79/80 when us newbies, going through the rating process on FPO and SMC, weren't considered good enough to be invited for lunch at Jessie's with the 'elite' TWR and APP controllers after the morning shift.

Nah, fanciful, and what's the odds? - I doubt our paths have ever crossed.

[Plazbot]

Talking about enjoyment. You can earn money being a rent boy, a ditch digger or a race car driver. I know which I would prefer. Procedural control is an exercise in futility. If you calculate long enough they end up being separated by default. :ugh:

[HEATHROW DIRECTOR]

I've already said this but I too enjoyed procedural control. For one thing, it taught me good strip marking which stayed with me all my working life.

[Howabout]

Plazbot,

Disregard the interim comment as regards history. If you would prefer being a rent-boy, rather than doing procedural control, that's fine with me. It's only your ass, not the public's.

Spot on HD. I agree totally regarding keeping strips up to date. Stays with you for the rest of your time.