Outdated ATC Procedures
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Outdated ATC Procedures
For you older ATCO's, where do the following procedures come from and why are they still being used:
Go around not below 400ft when the runway is occupied for all a/c types.
VMC climbs and decents, where is this used?
Separation of SVFR and IFR, why? surely this means that VFR and IFR should be separated as well.
Why are training a/c cleared for a low approach and go around when they will anyway if no clearance received.
How about this:
Why, in todays high tech aviation environment, can't an a/c be cleared to maintain its own separation from a preceeding a/c (ahead into the same airport) using TCAS. I've seen it happen. It can be radar monitered from approach very safely.
Why at some ATC Units are the Rules of the MATS Pt 1 broken for traffic reasons and at other units not.
Why can't all the UK Aviation Professionals get together and form some sort of a committee to iron out all the old ambiguous procedures and form new procedures to cope with the fast moving Aviation Industry. Just seems to me that technology is moving faster than us mere mortals can accept or keep up with.
Go around not below 400ft when the runway is occupied for all a/c types.
VMC climbs and decents, where is this used?
Separation of SVFR and IFR, why? surely this means that VFR and IFR should be separated as well.
Why are training a/c cleared for a low approach and go around when they will anyway if no clearance received.
How about this:
Why, in todays high tech aviation environment, can't an a/c be cleared to maintain its own separation from a preceeding a/c (ahead into the same airport) using TCAS. I've seen it happen. It can be radar monitered from approach very safely.
Why at some ATC Units are the Rules of the MATS Pt 1 broken for traffic reasons and at other units not.
Why can't all the UK Aviation Professionals get together and form some sort of a committee to iron out all the old ambiguous procedures and form new procedures to cope with the fast moving Aviation Industry. Just seems to me that technology is moving faster than us mere mortals can accept or keep up with.
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In that I don't have time at the moment to address more than one of these issues...
Just a few thoughts among many:
1. Because the second aircraft has not been positively identified by the first.
2. Because the device is not certified for this use.
3. Crew workload.
4. Is it your intention that TCAS be treated like visual separation or like RADAR separation? Are you going to let the following aircraft get as close as he likes to the preceeding aircraft (like visual), or does the following aircraft need to stay a certain distance away (RADAR)? Better not be the former, because this ain't visual separation. If it’s the latter, see the rest of this post. What’s more, where’s the comfort level? If I need three miles between these two aircraft because they’re not using visual separation, how much do I need to build in for safety and my own sanity? Efficiency goes to hell pretty quickly in this scenario. I mean, does using TCAS mean that the separation between participating aircraft needs to be doubled? If so, where’s the benefit? That’s a lot of wasted sky, and obviously you’re not going to have fewer aircraft.
5. ATC workload. Prying them apart when it goes to hell will be harder than just working the traffic in the first place.
6. How are you going to ensure the TCAS is calibrated on an ongoing basis? Both the tracker and the trackee are moving and data are essentially derived from secondary beacons. Can you even SEE primary targets on TCAS?
7. Me: "American 352 do you have TCAS contact with that target at 1 o'clock and 8 miles descending through 9000? You can plan to follow him to the airport."
Pilot: "Ah, approach, yeah we see somebody on the TCAS here but he's more like 1:30 and 6 miles. Is that him?"
Me: "Hell, I don't know. Which way's he headed?"
Pilot: "Pretty much southbound, but it looks like he's turning to the east now."
Me: "Delta 1215 turn left heading 090 for TCAS identification by traffic trying to follow you..."
Delta Pilot: "Approach are you telling me you've lost RADAR contact with us? Has our transponder puked or something?"
Me: "No sir. I can see you just fine. I just need you to give me a 45 degree turn so that American can ID you and follow you to the airport."
Delta Pilot: "Doesn't that seem like a waste of time, money, and airspace?"
Me: "Sure does. But don't blame me. It was the idea of that guy on PPRuNe..."
8. Cost/benefit analysis says the threat of bad stuff happening outweighs the potential benefit which could be derived over time.
Illustration:
15 or so years ago... I'm working departures. Orbiting just north of the primary airport at 8000 or so is a US Army Queenair (general equivalent) and working with him is a Mohawk. They're doing icing research. One is spraying the other with liquid in various conditions and at various altitudes/temps/dewpoints/etc. They work together for a while, then split up for a while, and this goes on and on. They drone around at 150 knots or so for hours on end.
Tower has a flight of two F-16s for departure (Rwy 27). Vis isn't bad, but the ceiling is kind of low. So the F-16s stagger their departure by (as I recall) 30 seconds. First one rolls. 30 seconds later, second one, having acquired the first one on his RADAR, rolls. The flight leader checks in with me and I RADAR identify him (they're still a flight of two but they're not yet joined up). I see the primary target on the second aircraft. The flight leader has turned to a heading of around 310, but the trailing primary target--the second F-16--continues his right turn through 360. It then dawns on me. The second F-16 has acquired the Queenair instead of his wingman and is about to try to join up on it. Problem was that he was going to try to join up on an aircraft that was doing lazy 360s at 150 knots in IMC, while he himself was moving better than 300, and the paint didn't match. The Queenair was at the F-16's 12 o'clock and less than 5 miles by the time I got him turned.
Here's the rub: That F-16 had acquired that target using real RADAR designed to acquire other aircraft and carefully calibrated for the best performance possible. TCAS is a tool which is incredibly useful as a safety net for aircrews, but it was built with an eye toward being a last-ditch effort at keeping aircraft--ANY aircraft—apart. It's a stretch to try to shoehorn it into service where it would be used to identify and track a specific target. I’m not interested. As a tool providing another layer of anti-death, love it. To use it to ever-so-carefully slide airplanes into each other’s personal space will certainly result in pain.
Of course, that's just my opinion.
Dave
Oh yeah. I forgot the most important answer to ALL of your questions:
Because it was like that when I got here and it'll be like that when you leave.
Sorry. Had to use it at least once. When I was a whippersnapper the tired old bastards said it to me. I've always made it a point to NOT say crap like that to the young'uns, but having reread your post it seemed like a nice opportunity...
Dave
Why, in todays high tech aviation environment, can't an a/c be cleared to maintain its own separation from a preceeding a/c (ahead into the same airport) using TCAS. I've seen it happen. It can be radar monitered from approach very safely.
1. Because the second aircraft has not been positively identified by the first.
2. Because the device is not certified for this use.
3. Crew workload.
4. Is it your intention that TCAS be treated like visual separation or like RADAR separation? Are you going to let the following aircraft get as close as he likes to the preceeding aircraft (like visual), or does the following aircraft need to stay a certain distance away (RADAR)? Better not be the former, because this ain't visual separation. If it’s the latter, see the rest of this post. What’s more, where’s the comfort level? If I need three miles between these two aircraft because they’re not using visual separation, how much do I need to build in for safety and my own sanity? Efficiency goes to hell pretty quickly in this scenario. I mean, does using TCAS mean that the separation between participating aircraft needs to be doubled? If so, where’s the benefit? That’s a lot of wasted sky, and obviously you’re not going to have fewer aircraft.
5. ATC workload. Prying them apart when it goes to hell will be harder than just working the traffic in the first place.
6. How are you going to ensure the TCAS is calibrated on an ongoing basis? Both the tracker and the trackee are moving and data are essentially derived from secondary beacons. Can you even SEE primary targets on TCAS?
7. Me: "American 352 do you have TCAS contact with that target at 1 o'clock and 8 miles descending through 9000? You can plan to follow him to the airport."
Pilot: "Ah, approach, yeah we see somebody on the TCAS here but he's more like 1:30 and 6 miles. Is that him?"
Me: "Hell, I don't know. Which way's he headed?"
Pilot: "Pretty much southbound, but it looks like he's turning to the east now."
Me: "Delta 1215 turn left heading 090 for TCAS identification by traffic trying to follow you..."
Delta Pilot: "Approach are you telling me you've lost RADAR contact with us? Has our transponder puked or something?"
Me: "No sir. I can see you just fine. I just need you to give me a 45 degree turn so that American can ID you and follow you to the airport."
Delta Pilot: "Doesn't that seem like a waste of time, money, and airspace?"
Me: "Sure does. But don't blame me. It was the idea of that guy on PPRuNe..."
8. Cost/benefit analysis says the threat of bad stuff happening outweighs the potential benefit which could be derived over time.
Illustration:
15 or so years ago... I'm working departures. Orbiting just north of the primary airport at 8000 or so is a US Army Queenair (general equivalent) and working with him is a Mohawk. They're doing icing research. One is spraying the other with liquid in various conditions and at various altitudes/temps/dewpoints/etc. They work together for a while, then split up for a while, and this goes on and on. They drone around at 150 knots or so for hours on end.
Tower has a flight of two F-16s for departure (Rwy 27). Vis isn't bad, but the ceiling is kind of low. So the F-16s stagger their departure by (as I recall) 30 seconds. First one rolls. 30 seconds later, second one, having acquired the first one on his RADAR, rolls. The flight leader checks in with me and I RADAR identify him (they're still a flight of two but they're not yet joined up). I see the primary target on the second aircraft. The flight leader has turned to a heading of around 310, but the trailing primary target--the second F-16--continues his right turn through 360. It then dawns on me. The second F-16 has acquired the Queenair instead of his wingman and is about to try to join up on it. Problem was that he was going to try to join up on an aircraft that was doing lazy 360s at 150 knots in IMC, while he himself was moving better than 300, and the paint didn't match. The Queenair was at the F-16's 12 o'clock and less than 5 miles by the time I got him turned.
Here's the rub: That F-16 had acquired that target using real RADAR designed to acquire other aircraft and carefully calibrated for the best performance possible. TCAS is a tool which is incredibly useful as a safety net for aircrews, but it was built with an eye toward being a last-ditch effort at keeping aircraft--ANY aircraft—apart. It's a stretch to try to shoehorn it into service where it would be used to identify and track a specific target. I’m not interested. As a tool providing another layer of anti-death, love it. To use it to ever-so-carefully slide airplanes into each other’s personal space will certainly result in pain.
Of course, that's just my opinion.
Dave
Oh yeah. I forgot the most important answer to ALL of your questions:
Because it was like that when I got here and it'll be like that when you leave.
Sorry. Had to use it at least once. When I was a whippersnapper the tired old bastards said it to me. I've always made it a point to NOT say crap like that to the young'uns, but having reread your post it seemed like a nice opportunity...
Dave
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Why can't all the UK Aviation Professionals get together and form some sort of a committee to iron out all the old ambiguous procedures and form new procedures to cope with the fast moving Aviation Industry
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To take each point in turn:
Would you rather they came down to 1 or 2 feet above the obstruction (be it aircraft or work in progress)? I've seen the results of this (though not on a runway) - it's not pretty! 400ft gives a nice amount of clearance without either side suffering the 'sphincter' factor.
You obviously don't have, and don't use, a procedural approach rating. If you refer back to MATS part 1 it does state that it's only to be used when radar is not available. Guess what - there are units out there that still operate in that way.
They'd better not! If they're cleared for a low approach and go around they can come down to whatever height they like above the runway and fly down its full length. If they're not then they break off the approach and fly the missed approach procedure (if instrument) or a go-around which keeps them away from the runway (normally deadside if there is such a monster) if it's from a visual approach.
Agree with everything av8boy says.
Would you like to quote examples? I've never seen it happen and people get away with it. More often than not it happens and you end up in a one sided conversation with SRG. 99.9% of ATCO's will abide with MATS pt 1 to the letter, such is their professionalism. Back this statement up with facts or be prepared for someone to acuse you of libel/slander.
Go around not below 400ft when the runway is occupied for all a/c types
VMC climbs and decents, where is this used?
Why are training a/c cleared for a low approach and go around when they will anyway if no clearance received.
Why, in todays high tech aviation environment, can't an a/c be cleared to maintain its own separation from a preceeding a/c (ahead into the same airport) using TCAS. I've seen it happen. It can be radar monitered from approach very safely
Why at some ATC Units are the Rules of the MATS Pt 1 broken for traffic reasons and at other units not.
Last edited by Chilli Monster; 17th Dec 2003 at 17:30.
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Go around not below 400ft. This was brought in after a near disaster with a go around and an occupied runway. Vague memory about a VC10 on the runway with an African airline training or diverting. The a/c going around actually touched the tail of the VC10. 
It was in the era of the Teneriffe disaster and made the CAA a bit nervous so they imposed a blanket limit.
It was in the era of the Teneriffe disaster and made the CAA a bit nervous so they imposed a blanket limit.
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Loki If my memory serves me the collision of Trident/Comet (definitely Bedford, 1968???) was the result of the Captain thinking the First Officer was doing it, the First Officer thinking the auto-pilot was doing it and the auto-pilot being er, not selected. Basically, no-one was doing it. Some such scenario anyway. I think the 400ft rule came in a lot later.
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Now sober, have been thinking about the 400ft rule which applieis to any a/c. B744, B772, C150 7 R22. Surely there must be a differentation between these a/c rather than not below 400ft for all a/c.
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What's this 400' rule? As I understood it, if you're not cleared to land the only restriction is that you may not, er, land - no minimum height exists that I know of (apart from DA without vis. ref.). Be interested to know if someone knows differently - with reference?. The only min. height on approach without landing clearance that I do know of is in my own co. ops manual and that is 200'R but that only applies to Cat II or III approaches.
Last edited by NW1; 18th Dec 2003 at 07:02.
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UK Manual of Air Traffic Services Part 1
If the runway in use is occupied by aircraft or vehicles, an approaching aircraft shall not be cleared to carry out a missed approach procedure which includes a descent below 400 feet above the threshold elevation. When the missed approach instruction is restricted to 400 feet or above the pilot is to be informed of the aircraft or vehicles on the runway.
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Spitoon
If I read this correctly: this applies to an aircraft intending to fly a missed approach (i.e. training)? Not only that - but if the intention of ATC is that the lowest height to be flown is 400' then that must be explicitly stated?
Very often I have received landing clearance in the UK significantly later than 400'R - as I wrote earlier, there is no operational rule we have requiring a minimum go-around height apart from visual reference below DA and landing clearance by 200'R in Cat II or III.
It is therefore possible that one could end up doing a go-around from, say, 20'R, for example, if no landing clearance is received due to an aircraft being slow to clear (although one's personal judgement would probably not take it that far)...... but I know of no-one going around at 400'R just because they got a "continue" instead of "clear to land".....
Very often I have received landing clearance in the UK significantly later than 400'R - as I wrote earlier, there is no operational rule we have requiring a minimum go-around height apart from visual reference below DA and landing clearance by 200'R in Cat II or III.
It is therefore possible that one could end up doing a go-around from, say, 20'R, for example, if no landing clearance is received due to an aircraft being slow to clear (although one's personal judgement would probably not take it that far)...... but I know of no-one going around at 400'R just because they got a "continue" instead of "clear to land".....
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Similar rule in the U.S., only the altitude is 500' or higher.....
------------------------------------------------------------------------
FAA 7110.65
3-10-10. ALTITUDE RESTRICTED LOW APPROACH
A low approach with an altitude restriction of not less than 500 feet above the airport may be authorized except over an aircraft in takeoff position or a departure aircraft. Do not clear aircraft for restricted altitude low approaches over personnel unless airport authorities have advised these personnel that the approaches will be conducted. Advise the approaching aircraft of the location of applicable ground traffic, personnel, or equipment.
NOTE-
1. The 500 feet restriction is a minimum. Higher altitudes should be used when warranted. For example, 1,000 feet is more appropriate for heavy aircraft operating over unprotected personnel or small aircraft on or near the runway.
2. This authorization includes altitude restricted low approaches over preceding landing or taxiing aircraft. Restricted low approaches are not authorized over aircraft in takeoff position or departing aircraft.
PHRASEOLOGY-
CLEARED LOW APPROACH AT OR ABOVE (altitude). TRAFFIC (description and location).
------------------------------------------------------------------------
FAA 7110.65
3-10-10. ALTITUDE RESTRICTED LOW APPROACH
A low approach with an altitude restriction of not less than 500 feet above the airport may be authorized except over an aircraft in takeoff position or a departure aircraft. Do not clear aircraft for restricted altitude low approaches over personnel unless airport authorities have advised these personnel that the approaches will be conducted. Advise the approaching aircraft of the location of applicable ground traffic, personnel, or equipment.
NOTE-
1. The 500 feet restriction is a minimum. Higher altitudes should be used when warranted. For example, 1,000 feet is more appropriate for heavy aircraft operating over unprotected personnel or small aircraft on or near the runway.
2. This authorization includes altitude restricted low approaches over preceding landing or taxiing aircraft. Restricted low approaches are not authorized over aircraft in takeoff position or departing aircraft.
PHRASEOLOGY-
CLEARED LOW APPROACH AT OR ABOVE (altitude). TRAFFIC (description and location).
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Ref replies along the lines of everyone 'doing it by the book', good friend of mine given a 'land after' at a SW airfied as a 146 backtracked the runway! Think 'land over' was removed some time ago.
The 'clear low approach and go-around' has always been the best way for a legitimate beat up , long may it continue....
The 'clear low approach and go-around' has always been the best way for a legitimate beat up , long may it continue....
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Okay, here goes on the TCAS separation question (deep breath):
The 4-quadrant phased-array patch antenna on board an a/c cannot obtain a bearing to better than a few degrees on another transponder (although range accuracy is good), certainly not good enough for positive ID. TCAS targets aren't processed by the FMC mapping computers, but injected directly into the symbol generators: therefore exact lat/long of target is impossible to process and hence track by the FMC nav kit. Hence TCAS isn't considered accurate enough for your suggested use (although it's extremely good at what it IS certified for).
And there, ladies and gentlemen, is the reason girls won't talk to me at parties....
The 4-quadrant phased-array patch antenna on board an a/c cannot obtain a bearing to better than a few degrees on another transponder (although range accuracy is good), certainly not good enough for positive ID. TCAS targets aren't processed by the FMC mapping computers, but injected directly into the symbol generators: therefore exact lat/long of target is impossible to process and hence track by the FMC nav kit. Hence TCAS isn't considered accurate enough for your suggested use (although it's extremely good at what it IS certified for).
And there, ladies and gentlemen, is the reason girls won't talk to me at parties....
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My Turn <G>....
The VMC or VFR climb or decent is used in the US, but the pilot must ask for it. It works rather nicely too when say a slower aircraft is stuck at a lower altitude and getting bounced about and wants higher. However four altitudes above him/her are other aircraft all over taking. The flower flib requests a VFR climb to the altitude that is available and is able to get it. We provide traffic advisories and the only separation that we are concerned about is not trading paint. Much better than the five miles that we must use enroute.
The SVFR vrs. IFR separation thing. The only time that you are using SVFR is when the weather is really stinko, well at least for the US, I am sure that might be a nice summer day in the UK <Big Evil Grin>. You use some sort of separation service because the weather just isn't good enough for see and avoid.
Now the TCAS thing. That has been brought up already. However, that sort of thing was looked at and discounted in a busy environment. You can't verify that the aircraft you are looking at is the one that you are trying to separate from. However, in the not to distant future with the advent of ADS-B being used, we might indeed be able to do something along the lines of electronic visual separation. I don't see pilots using it for IFR mileage type separation though. Workload in the cockpit would go up and the pilots aren't too keen that have tested it on being tasked with a deal if they get just a tad too close. We as controllers aren't to keen on the idea of a pilot thinking that I can do this, and then up to the last moment think, oh crap, this isn't going to work, let me give it back to the controller. It just doesn't work well that way. The only reason that we would want to do anything along these lines would be to be able to handle more aircraft. If you can't trust that the pilot is going to do the job of self separation, then you can't handle more aircraft, because you are always going to have to watch what they are doing... Oh, add to that you don't know what the pilot is doing to try to keep that separation, that makes it just that much harder. We do what we do by knowing what a pilot is doing.
regards
Scott
The VMC or VFR climb or decent is used in the US, but the pilot must ask for it. It works rather nicely too when say a slower aircraft is stuck at a lower altitude and getting bounced about and wants higher. However four altitudes above him/her are other aircraft all over taking. The flower flib requests a VFR climb to the altitude that is available and is able to get it. We provide traffic advisories and the only separation that we are concerned about is not trading paint. Much better than the five miles that we must use enroute.
The SVFR vrs. IFR separation thing. The only time that you are using SVFR is when the weather is really stinko, well at least for the US, I am sure that might be a nice summer day in the UK <Big Evil Grin>. You use some sort of separation service because the weather just isn't good enough for see and avoid.
Now the TCAS thing. That has been brought up already. However, that sort of thing was looked at and discounted in a busy environment. You can't verify that the aircraft you are looking at is the one that you are trying to separate from. However, in the not to distant future with the advent of ADS-B being used, we might indeed be able to do something along the lines of electronic visual separation. I don't see pilots using it for IFR mileage type separation though. Workload in the cockpit would go up and the pilots aren't too keen that have tested it on being tasked with a deal if they get just a tad too close. We as controllers aren't to keen on the idea of a pilot thinking that I can do this, and then up to the last moment think, oh crap, this isn't going to work, let me give it back to the controller. It just doesn't work well that way. The only reason that we would want to do anything along these lines would be to be able to handle more aircraft. If you can't trust that the pilot is going to do the job of self separation, then you can't handle more aircraft, because you are always going to have to watch what they are doing... Oh, add to that you don't know what the pilot is doing to try to keep that separation, that makes it just that much harder. We do what we do by knowing what a pilot is doing.
regards
Scott
Happens quite a bit in French airspace as well, we sometimes asked if we are visual with another aircraft and if we are happy for them to climb through our level. Seems to work well.