"rule of thumb" in procedural control
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...
2 s 
Aircraft A, a DC3, crosses POL 10 min ahead of Aircraft B, a DC4 = separated.
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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).
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).
Last edited by Howabout; 1st Jun 2013 at 15:22.
Howabout
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?
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?
Last edited by Brian 48nav; 1st Jun 2013 at 20:08. Reason: Addition
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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!
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!
Last edited by Howabout; 2nd Jun 2013 at 14:31.
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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.
I felt like a lost procedural cadet again with all the various equations I'd never heard of after the first page.
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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.
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.
Last edited by Howabout; 4th Jun 2013 at 08:09.
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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.
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.
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.
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.
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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!
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!
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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!
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!
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<<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!
You mean like the bloke I had at Heathrow once who thought he could do GMC using PERT diagrams!
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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!'
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!'
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.
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.
Last edited by Brian 48nav; 5th Jun 2013 at 08:35. Reason: Addition