Why they do that? a Q&A with NY approach.
11-30-2010, 10:28 PM
#101
Gets Weekends Off
Joined APC: May 2009
Posts: 223
Ajax thanks for answering so many questions. I realize that we can't save time and fuel and like the other guy said its not about saving fuel as much as knowing how much farther I have to fly to get to the runway so I have a better idea of when to pull the plug and head somewhere else.
I understand the zig zag works best to get the tight spacing which is good. The downside for us is the zig zag takes away some info that could help us from being the next Avianca. My company says we are supposed to declare min fuel when it looks like we will burn into our reserve fuel. If I don't know how far I have to fly to get to the runway its a little harder for me to come up with a number to use to declare min fuel.
I understand the zig zag works best to get the tight spacing which is good. The downside for us is the zig zag takes away some info that could help us from being the next Avianca. My company says we are supposed to declare min fuel when it looks like we will burn into our reserve fuel. If I don't know how far I have to fly to get to the runway its a little harder for me to come up with a number to use to declare min fuel.
11-30-2010, 10:43 PM
#102
Gets Weekends Off
Joined APC: Jul 2009
Position: ERJ145 Captain
Posts: 473
Ajax,
I appreciate you taking time to answer questions on this forum, and please don't take my question/remarks personally as they're neither directed at you nor accusing you, but rather the product of experience.
Let's talk separation. There are two major flaws going into EWR:
22L/4R - Visual, let's understand each other here from pilot to controller. If you clear me for a visual and I'm following a heavy, why do you bother giving me a speed? I am going to maintain 5 miles separation whether it complies with your speed or not, as separation is now my concern. Many times I've gone into EWR, given a "follow the traffic, clear for the visual, maintain 180 to the marker", then the heavy will slow early, and we do as well to maintain separation, then either tower or approach will get their panties in a bunch because we slowed down. I will maintain separation, no matter what speed you give me, and if that's not something you're interested in then don't clear me for a visual and do your job. The alternative would be to either go around or to not accept the visual. So what say you?
11 visual - You guys apparently seem to think that instead of executing a go around on 11 (because the 737 on approach to 22L was too good to comply with instructions) that you can ask for a circle to land on 22R. Well my friend, that's all nice and good if you're above 1000', but not below. Our book specifically states that we cannot circle to land below 1000'. Expect a big fat UNABLE in the near future if you decide to give us a circle to land for 22R from 11 inside of a thousand feet. Instead why don't you guys ask the CAL 737 on approach to 22L to go around?
I appreciate you taking time to answer questions on this forum, and please don't take my question/remarks personally as they're neither directed at you nor accusing you, but rather the product of experience.
Let's talk separation. There are two major flaws going into EWR:
22L/4R - Visual, let's understand each other here from pilot to controller. If you clear me for a visual and I'm following a heavy, why do you bother giving me a speed? I am going to maintain 5 miles separation whether it complies with your speed or not, as separation is now my concern. Many times I've gone into EWR, given a "follow the traffic, clear for the visual, maintain 180 to the marker", then the heavy will slow early, and we do as well to maintain separation, then either tower or approach will get their panties in a bunch because we slowed down. I will maintain separation, no matter what speed you give me, and if that's not something you're interested in then don't clear me for a visual and do your job. The alternative would be to either go around or to not accept the visual. So what say you?
11 visual - You guys apparently seem to think that instead of executing a go around on 11 (because the 737 on approach to 22L was too good to comply with instructions) that you can ask for a circle to land on 22R. Well my friend, that's all nice and good if you're above 1000', but not below. Our book specifically states that we cannot circle to land below 1000'. Expect a big fat UNABLE in the near future if you decide to give us a circle to land for 22R from 11 inside of a thousand feet. Instead why don't you guys ask the CAL 737 on approach to 22L to go around?
11-30-2010, 11:09 PM
#103
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Thread Starter
Joined APC: Nov 2010
Position: N90-EWR
Posts: 91
Yeah, compression, I keep hearing that word. J.K. gave me a bit of an explanation on this, but I'm still not sure understand what it is and what causes it. Is it essentially caused just by strong winds making aircraft on downwind fly super fast over the ground while aircraft on final go super slow? Groundspeed difference? Is that it? Are slow groundspeeds on the approach the culprit then? And are AARs spit out by a computer at flow control, or is there any human input? Can an individual facility (i.e. ZDC, N90, LGA ATCT, etc), influence these numbers?
Is this even an issue when winds aren't doing anything out of the ordinary? JFK doesn't seem to have too many problems with delays caused by ceilings, but LGA seems to go into delays even with, say a 2,000ft CIG. I could never figure out why. And when you say "use visual separation" does that refer to the tower controller visually monitoring arrivals?
Well, yeah, what I was getting at was why, going into JFK, we sometimes get slowed, and vectored out, and then when on the final and switched over to tower they say, "you're 7 miles behind an RJ, cleared to land." I understand if we have that kind of spacing behind a 777, but another RJ?? And not even during a staggered approach with another close parallel. Not saying that sort of thing happens often, but it never happens at LGA. If you're following another RJ at LGA, you're going to be 3 miles behind him as he's touching down. I guess this might be an instance where a controller might be over-cautious at times!
Although our 3 "big airports" are very busy, we do have some slow times here and there. Extra spacing on final could just be that...you may had come at a slow time, and the only one in front of you was already way ahead. There are many reasons why there could be extra spacing, so its very hard for me to cite them all. I've provided extra space on the EWR final to allow for an IFR19 out of TEB, because you can't legally depart RWY 19 out of TEB when EWR is landing 22L (this is why they have the infamous Dalton departure) without a gap. An aircraft landing on 22L may see that 8 mile gap and think "what a waste of space". Other times Port Authority calls the tower asking for a quick runway sweep, the tower calls approach and we provide an extra gap so that they can send a vehicle in. Like I said...too many variables.
When landing 22L, can you run simultaneous visual approaches with 22R if departure demand allows? I know you can do it sparingly for 4L/4R, but don't recall it ever being done for the 22's.
Also, it seems like no matter how far north the 22L downwind goes, it seems the base follows a very fine track, almost like a 150ish heading towards TEB. I'm presuming you can't have a long (20NM) final to 22L and that the final has to start over TEB? I know another airport is right there, I woulda just thought that you could have the airspace north of TEB as well, as a EWR arrival would be well above any TEB traffic.
I understand LGA ILS13 all but shuts down TEB, but what kind of impact (if any) does that operation (along with JFK ILS13L) have on EWR?
11-30-2010, 11:33 PM
#104
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Joined APC: Nov 2010
Position: N90-EWR
Posts: 91
I appreciate you taking time to answer questions on this forum, and please don't take my question/remarks personally as they're neither directed at you nor accusing you, but rather the product of experience.
Let's talk separation. There are two major flaws going into EWR:
22L/4R - Visual, let's understand each other here from pilot to controller. If you clear me for a visual and I'm following a heavy, why do you bother giving me a speed? I am going to maintain 5 miles separation whether it complies with your speed or not, as separation is now my concern. Many times I've gone into EWR, given a "follow the traffic, clear for the visual, maintain 180 to the marker", then the heavy will slow early, and we do as well to maintain separation, then either tower or approach will get their panties in a bunch because we slowed down. I will maintain separation, no matter what speed you give me, and if that's not something you're interested in then don't clear me for a visual and do your job. The alternative would be to either go around or to not accept the visual. So what say you?
11 visual - You guys apparently seem to think that instead of executing a go around on 11 (because the 737 on approach to 22L was too good to comply with instructions) that you can ask for a circle to land on 22R. Well my friend, that's all nice and good if you're above 1000', but not below. Our book specifically states that we cannot circle to land below 1000'. Expect a big fat UNABLE in the near future if you decide to give us a circle to land for 22R from 11 inside of a thousand feet. Instead why don't you guys ask the CAL 737 on approach to 22L to go around?
Let's talk separation. There are two major flaws going into EWR:
22L/4R - Visual, let's understand each other here from pilot to controller. If you clear me for a visual and I'm following a heavy, why do you bother giving me a speed? I am going to maintain 5 miles separation whether it complies with your speed or not, as separation is now my concern. Many times I've gone into EWR, given a "follow the traffic, clear for the visual, maintain 180 to the marker", then the heavy will slow early, and we do as well to maintain separation, then either tower or approach will get their panties in a bunch because we slowed down. I will maintain separation, no matter what speed you give me, and if that's not something you're interested in then don't clear me for a visual and do your job. The alternative would be to either go around or to not accept the visual. So what say you?
11 visual - You guys apparently seem to think that instead of executing a go around on 11 (because the 737 on approach to 22L was too good to comply with instructions) that you can ask for a circle to land on 22R. Well my friend, that's all nice and good if you're above 1000', but not below. Our book specifically states that we cannot circle to land below 1000'. Expect a big fat UNABLE in the near future if you decide to give us a circle to land for 22R from 11 inside of a thousand feet. Instead why don't you guys ask the CAL 737 on approach to 22L to go around?
What you're saying makes perfect sense, but to be brutally honest, when we're issuing visual approach clearances, we're doing it to run a super tight final that would be illegal for us to do otherwise. The aircraft behind you is doing the same speed and if you slow down, its going to compress a lot, to the point that either him, or the one behind most likely will end up going around. This is the reason why a lot of controllers are very hesitant to give visual clearances when its really busy, and only use it as a last resort bailout. If you refuse a visual, you will be sent around or taken out of line for resequence. its not uncommon to spend another 20 to 30 minutes flying for resequence.
I'm going to throw a question out to you pilots...are you able to safely fly on final and land behind a heavy/B757 with less than 5 miles by staying "above" the descent profile of that heavy? I may be wrong, but I was under the impression that if you stayed at a higher profile/angle, and touched down at a point further down the runway than the heavy, that you would stay above such wake. Again, I'll confess I'm not a pilot, so I may be misinformed on this.
As for the second question. Normally...we don't do visuals to Rwy 11 anymore. In the past we did on ocasion, but after CRDA rwy 11 final was created RWY 11 arrivals are only ILS11. I haven't seen many circle for 22R since we opened CRDA, but...in any case, if and when that happens, that is never ever initiated by us. That is something the tower would initiate, and as far as I know, very rarely would the tower send a rwy 11 arrival around if there was a conflict with a 22L arrival, because a rwy 11 go around is a mess that is not easy to clean up for us. If you go straight out...you're in the river dancing with the LGA traffic. if you turn right, you're dancing with our departures, if you turn left you're head on with the arrivals and/or the TEB departures. Trust me when I tell you...if you're set up for 11, we all want you landing, and the one going around is usually the 22L arrival.
Which brings me to another observation. Watching the Singapore heavy coming from Kuala Lumpur go around because of a conflict with a Rwy 11 Colgan arrival that took off 35 minutes ago makes me cringe my teeth every time it happens. Not fair but its just easier for the tower to have a 22L go around than the 11.
12-01-2010, 05:26 AM
#105
Gets Weekends Off
Joined APC: Mar 2010
Posts: 1,951
If you are 500' above or below a VFR King Air, you *are* separated - we only need 500' between a VFR and IFR, even in class B (heavies and 757s are the exception). If a controller issues that traffic, you can ask for a vector around or away from him and the controller is supposed to make an effort to do that. You're right, in class E, we don't *have* to even do that, but I don't know any controllers who would let you run right at another target, same altitude, and not try to get you away from it.
It sounds like TCAS and the FAA's minimums don't agree. My personal feeling is that if I called the traffic, and they're both level at least 500' apart, I do nothing unless a pilot asks for a turn away from them. The reason is that early in my career, I was asked by a pilot why I was turning his airplane when the other guy was level 500' above him.
So, if someone wants a turn away, I will give it to them. If they say nothing, I let them run because it's safe and legal for me to do so.
It sounds like TCAS and the FAA's minimums don't agree. My personal feeling is that if I called the traffic, and they're both level at least 500' apart, I do nothing unless a pilot asks for a turn away from them. The reason is that early in my career, I was asked by a pilot why I was turning his airplane when the other guy was level 500' above him.
So, if someone wants a turn away, I will give it to them. If they say nothing, I let them run because it's safe and legal for me to do so.
I think most controllers don't understand that TCAS devices give us a traffic message if we are less than 1000' vertically and less than ~2 miles. We get an RA if we are 500' apart and less than ~1 mile. We are REQUIRED by SOP to comply with all RAs, even in VFR with traffic in sight. So while it's "legal" for you to provide 500' separation with a nonparticipating VFR aircraft, it causes both us and you considerable workload when we have to comply and report. It might be advantageous for you to just provide the vector or altitide spacing.
12-01-2010, 05:34 AM
#106
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Joined APC: Feb 2008
Position: Switch, Lever & Light Specialist
Posts: 1,065
1-Arrival rates are determined by several factors, with the main one being the weather. Strong winds will lower arrival rates because of extra compression on final means we need extra spacing buffer on final to account for that. Low ceilings means visual separation may not be possible, and we running bare minimum IFR separation without the ability to use visual to prevent a compression error is too risky. Other reasons are runway configurations, runway closures on secondary (overflow) runways, departure demand, special activities (VIP movement, law enforcement operations in progress, etc). I've even seen controller staffing (or lack of) be a factor for a lower rate, although the FAA will go to extremes to avoid citing that as a reason (even if its true).
2-Even if technically the required minimun IFR separation is the same, once the ceilings/visibility drops, and we (and the tower) lose the ability to use visual separation, we need a bigger buffer on final to avoid compression "deals".
3-Many controllers are reluctant to issue a visual unless you're already straight in on final behind the traffic at a compatible distance and speed.When a controller issues a "follow that traffic, cleared visual approach rwy 22L" clearance, he is passing to you the burden of separation between your aircraft, and the one you're following, but is giving you control to manouver the aircraft as you see fit to maintain separation, and make an approach to the runway behind that traffic. The problem with this is that not every pilot will react exactly the same way, and while some will stay nice and tight behind the traffic, others give themselves and extra buffer, and may delay a turn from base to final, or make a very wide turn. If there is not much going on it doesn't matter much, but if its very busy, that may impact the traffic I have behind you.
Also, anyone and their uncle can run a visual approach final, as the need for good timing, precision vectors and speed control is lessened, since we're passing that to you. It is considered "harder" or more "skilled" to run a nice tight, even spaced IFR final, and thus this is how we run the final when we're training new controllers. Not saying we would never run visuals, because we do, but running visual approaches all the time is a crutch, and when the proverbial sh*t hits the fan, and the wx goes down, you better be able to handle it. To give you a comparison you can relate...would you train your pilots to always depend on autopilot, and autolandings?
4- Although I don't know the exact number, a great % of JFK traffic is heavy jets/b757's that require wake turbulence separation. EWR and LGA have less heavy jet traffic so its not unusual to see our finals tighter than JFK's. Having said that I'm going to repost something here that I posted on another forum while I was trying to answer a similar question, but using CLT instead of JFK.
The original question was " why does CLT run 5 mile spacing on final to landing only runways. While LGA, ORD, etc run 3 miles."
My reply was:
"I don't know the CLT operation, so I wont coment on their specifics, but I think I know where he's going with that questioning, and I'll try to answer with what happens here @ N90, and in particular my area (EWR)
Not all controllers are created equal, just like not all pilots are created equal. Some controllers are just....good for lack of any fancy words, and can run a very tight final. Others may not be that sharp, and run extra spacing for "safety". There are other factors to add to those 2 categories. There are controllers that tend to be a bit more aggressive, and there are some that, even if they have the "skills" to run a very tight final, they prefer to be conservative, and build in a little extra spacing buffer.
It all comes down to local culture. In my area, the "aggressive" controller tends to be more the norm than the exception (but we do have exceptions), and thus our finals tend to be pretty tight most of the time. It is engrained in the sector culture to run traffic this way and trainees are trained in this matter, supervisors encourage it, etc. In other places, the predominant type is the other, and thus people are trained to run bigger buffers.
I've visited several other facilities, and also noticed what he's talking about. I've seen other places run 5 mile final on everything, and do like 6 or 7 behind heavy's."
5-Windshear reduces the arrival rates because the potential for go arounds is higher. Every go around becomes .....an extra arrival.
6-The EWR downwind is super wide because departures out of EWR, TEB, MMU, and CDW need a climbout corridor to be able to get on top of the arrivals. The boundary line goes from MMU to CDW to TEB, so that is why you normally get vectored to stay on the outside, and make the wide turn. In addition, when its busy, the downwind can, and often extend all the way to SAX and is not uncommon to turn base over 4N1 (Greenwood lake airport).
As for the other question regarding departures staying @ 17000 for long distances. The Liberty sector (the area that takes all the departures from all the airports and gets traffic over all the different fixes in trail for ZNY) only "owns" up to 17000. Above them is ZNY, and they have inbound JFK arrivals descending to FL 190, so until Liberty hands you off to the center, and they have you cleared of any inbounds, you're going to be stuck below them. Doesn't happen all the time, but some airports (like HPN) have greater distances to fly, and will be leveled at 17000 for longer. Just the nature of the airspace.
2-Even if technically the required minimun IFR separation is the same, once the ceilings/visibility drops, and we (and the tower) lose the ability to use visual separation, we need a bigger buffer on final to avoid compression "deals".
3-Many controllers are reluctant to issue a visual unless you're already straight in on final behind the traffic at a compatible distance and speed.When a controller issues a "follow that traffic, cleared visual approach rwy 22L" clearance, he is passing to you the burden of separation between your aircraft, and the one you're following, but is giving you control to manouver the aircraft as you see fit to maintain separation, and make an approach to the runway behind that traffic. The problem with this is that not every pilot will react exactly the same way, and while some will stay nice and tight behind the traffic, others give themselves and extra buffer, and may delay a turn from base to final, or make a very wide turn. If there is not much going on it doesn't matter much, but if its very busy, that may impact the traffic I have behind you.
Also, anyone and their uncle can run a visual approach final, as the need for good timing, precision vectors and speed control is lessened, since we're passing that to you. It is considered "harder" or more "skilled" to run a nice tight, even spaced IFR final, and thus this is how we run the final when we're training new controllers. Not saying we would never run visuals, because we do, but running visual approaches all the time is a crutch, and when the proverbial sh*t hits the fan, and the wx goes down, you better be able to handle it. To give you a comparison you can relate...would you train your pilots to always depend on autopilot, and autolandings?
4- Although I don't know the exact number, a great % of JFK traffic is heavy jets/b757's that require wake turbulence separation. EWR and LGA have less heavy jet traffic so its not unusual to see our finals tighter than JFK's. Having said that I'm going to repost something here that I posted on another forum while I was trying to answer a similar question, but using CLT instead of JFK.
The original question was " why does CLT run 5 mile spacing on final to landing only runways. While LGA, ORD, etc run 3 miles."
My reply was:
"I don't know the CLT operation, so I wont coment on their specifics, but I think I know where he's going with that questioning, and I'll try to answer with what happens here @ N90, and in particular my area (EWR)
Not all controllers are created equal, just like not all pilots are created equal. Some controllers are just....good for lack of any fancy words, and can run a very tight final. Others may not be that sharp, and run extra spacing for "safety". There are other factors to add to those 2 categories. There are controllers that tend to be a bit more aggressive, and there are some that, even if they have the "skills" to run a very tight final, they prefer to be conservative, and build in a little extra spacing buffer.
It all comes down to local culture. In my area, the "aggressive" controller tends to be more the norm than the exception (but we do have exceptions), and thus our finals tend to be pretty tight most of the time. It is engrained in the sector culture to run traffic this way and trainees are trained in this matter, supervisors encourage it, etc. In other places, the predominant type is the other, and thus people are trained to run bigger buffers.
I've visited several other facilities, and also noticed what he's talking about. I've seen other places run 5 mile final on everything, and do like 6 or 7 behind heavy's."
5-Windshear reduces the arrival rates because the potential for go arounds is higher. Every go around becomes .....an extra arrival.
6-The EWR downwind is super wide because departures out of EWR, TEB, MMU, and CDW need a climbout corridor to be able to get on top of the arrivals. The boundary line goes from MMU to CDW to TEB, so that is why you normally get vectored to stay on the outside, and make the wide turn. In addition, when its busy, the downwind can, and often extend all the way to SAX and is not uncommon to turn base over 4N1 (Greenwood lake airport).
As for the other question regarding departures staying @ 17000 for long distances. The Liberty sector (the area that takes all the departures from all the airports and gets traffic over all the different fixes in trail for ZNY) only "owns" up to 17000. Above them is ZNY, and they have inbound JFK arrivals descending to FL 190, so until Liberty hands you off to the center, and they have you cleared of any inbounds, you're going to be stuck below them. Doesn't happen all the time, but some airports (like HPN) have greater distances to fly, and will be leveled at 17000 for longer. Just the nature of the airspace.
As a person operating in/out of EWR all the time, your insight into the ATC side of the house is invaluable! I, along w/ many others, appreciate you taking the time to answer these questions. THANK YOU!!!
12-01-2010, 06:14 AM
#107
Gets Weekends Off
Joined APC: Jun 2008
Position: In the TRACON
Posts: 109
I have had this happen many, many times.
I think most controllers don't understand that TCAS devices give us a traffic message if we are less than 1000' vertically and less than ~2 miles. We get an RA if we are 500' apart and less than ~1 mile. We are REQUIRED by SOP to comply with all RAs, even in VFR with traffic in sight. So while it's "legal" for you to provide 500' separation with a nonparticipating VFR aircraft, it causes both us and you considerable workload when we have to comply and report. It might be advantageous for you to just provide the vector or altitide spacing.
I think most controllers don't understand that TCAS devices give us a traffic message if we are less than 1000' vertically and less than ~2 miles. We get an RA if we are 500' apart and less than ~1 mile. We are REQUIRED by SOP to comply with all RAs, even in VFR with traffic in sight. So while it's "legal" for you to provide 500' separation with a nonparticipating VFR aircraft, it causes both us and you considerable workload when we have to comply and report. It might be advantageous for you to just provide the vector or altitide spacing.
At MDW, for example, the tower keeps all their VFRs at 2000' or below within so many miles of the airport, while approach uses 2500' all the time for IFR arrivals on visual approaches (and 2500' is the FAF altitude on the runway 4R ILS; we use it for 31C usually, too). I've never had an IFR aircraft report a TCAS event when passing 500' above these VFRs in these situations -- but 30 miles away from the airport, it has happened on occasion.
Because VFRs are usually at 3500', 4500', 5500', etc, I try to give 1500' separation when possible, especially when I don't have the room to vector around them . . . but that's not always possible either.
Your best bet is to ask for a vector around the guy if you anticipate an RA. Some controllers would take your advice and would (or do already) try to vector you around, but there are always going to be some that do what the .65 says and nothing else, period.
Someone else had mentioned low ceilings affecting the arrival rate at an airport. Two big reasons --
1) When the tower can't provide visual separation between successive arrivals, controllers have to provide 2.5 or 3 miles (depending on the runway) all the way to touchdown. When the tower *can* provide visual, the distance between airplanes can go down to the acceptance rate of the runway, which can be more like 2.5 to 2 miles on final on runways with well-placed turnoffs.
2) This may only be true at some airports. Certain runway configurations might require 800' ceilings, or 1500' ceilings, or 2000' ceilings . . . the configurations that require higher ceilings are usually the ones that have the higher acceptance rate. I believe it is generally because of go-arounds. At ORD, we can run arrivals to 10, 14R and 22R -- none of the runways intersect, but if 2 airplanes went around at the same time, you can see it being a problem with a low overcast vs. a higher overcast day.
To sum up compression very easily -- Aircraft on final are doing 180 to the FAF at 4 miles-in-trail. Aircraft in the marker are slowing to a ground speed of 120 inside the FAF, which causes compression to reduce the separation to 3 miles or less. Some runways compress more than others due to wind -- maybe deflecting off of buildings or local phenomena, so they may run 5 miles instead of 4 on final.
12-01-2010, 07:49 AM
#108
Gets Weekends Off
Joined APC: Dec 2008
Position: B757/B767
Posts: 180
Haha, come on now! We can take it!
Yup, completely true. Generally speaking, the wake turbulence of any aircraft starts to sink not long after it's generated. When following a heavy (or hell, even a super), staying above the preceding aircraft's flight path will ensure that you avoid its wake. The practice in this scenario would be to fly a dot above the glideslope and aim to touchdown towards the end of the touchdown zone. However, this practice of flying a dot high is something we can only really do in good VFR weather, as in IFR weather we are required to stay on the IFR approach profile/glideslope until visual with the landing runway.
Again whether or not a flight can accept this practice of staying visually behind/above a heavy -- depends on the pilot! Flying above the glideslope is something that has to be handflown, as the autopilot has no practical way of maintaining vertical control at lower altitudes (below, say, 2000ft) if it's not following the ILS LOC/GS, and it can't be set to fly an offest from the ILS center beam (at least no aircraft that I've seen). Every airline has it's small share of "lazy" types that cannot be bothered to hanfly the aircraft, and will not turn off the autopilot until they absolutely have to. Flying an RJ in and out of JFK for the last several years, I'm very well versed in this practice, as are most of my colleagues. However there are some that won't do it, mostly out of laziness, and will not take a visual behind a heavy (at least without some serious spacing).
I've heard of instances where an aircraft's wake has hit the runway surface and then bounced back up into the air, above the generating aircraft's flight path as it enters the flare. However, this is only likely to be an issue for a light piston driver following a little too closely behind a large jet.
CRDA RWY 11 -- what is that like a position or something? Does CRDA stand for anything?
Hey speaking of lousy JFK ILS13L, LGA ILS13, TEB no-go type days, today looks like one of them. Have wx/winds like this ever gotten so bad that EWR would be up and down RWY 11 only? I understand some jets (typically heavy) can work with 35ish kt crosswinds, however for most transport category aircraft, the max demo crosswind is around 30kts. I know BTA, one of your most frequent customers, can only work with 30ish as that's the max-demo xwind component on a E145. CAL's mainline jets can probably do 30-35, but I can't speak for Boeings.
I'd be ****ed too if I just flew 18 hours and had to go around because of Colgan, lol! BTW, that flight comes in non-stop from Singapore, but I know what you're getting at.
Regarding 500' separation with a VFR target and TCAS RA, here's what I can tell you (and btw, this is pretty much standard amongst all FAR121 airlines. I'd imagine foreign carriers abide by the same):
1. If given a TCAS corrective RA (i.e. CLIMB, CLIMB/DESCEND, DESCEND), we MUST comply with the command unless it would be considered UNSAFE to do so. Our manual warns us not to ignore a corrective RA when having an aircraft visually in sight, as the aircraft we're seeing may not be the aircraft generating the RA. Also, TCAS commanded climbs/descents MUST be handflown (autopilot reaction time too slow, as George is programmed to fly smoothly).
2. Generally speaking, a corrective RA will only be issued when the TCAS detects any sort of vertical converging (i.e. loss of vertical distance between a target) -- i.e one of the aircraft involved is climbing or descending at a rate which causes the TCAS to compute that a conflict is probable in under 30 seconds.
Simply passing a steady 400-500ft above/below a target will usually not trigger a corrective RA if both aircraft are steadily maintaining altitude. This may, however generate a preventive RA (ADJUST VERTICAL SPEED/MONITOR VERTICAL SPEED), in which our TCAS/vertical speed indicator will will light up red in the direction of the target (upwards if the target is above, downwards if below), telling us, hey, you've got someone minimally separated above/below you -- do NOT climb/descend (again, depending on whether the target is above or below). In this case, we're not likely to vacate our assigned altitude.
I'm going to throw a question out to you pilots...are you able to safely fly on final and land behind a heavy/B757 with less than 5 miles by staying "above" the descent profile of that heavy? I may be wrong, but I was under the impression that if you stayed at a higher profile/angle, and touched down at a point further down the runway than the heavy, that you would stay above such wake. Again, I'll confess I'm not a pilot, so I may be misinformed on this.
Again whether or not a flight can accept this practice of staying visually behind/above a heavy -- depends on the pilot! Flying above the glideslope is something that has to be handflown, as the autopilot has no practical way of maintaining vertical control at lower altitudes (below, say, 2000ft) if it's not following the ILS LOC/GS, and it can't be set to fly an offest from the ILS center beam (at least no aircraft that I've seen). Every airline has it's small share of "lazy" types that cannot be bothered to hanfly the aircraft, and will not turn off the autopilot until they absolutely have to. Flying an RJ in and out of JFK for the last several years, I'm very well versed in this practice, as are most of my colleagues. However there are some that won't do it, mostly out of laziness, and will not take a visual behind a heavy (at least without some serious spacing).
I've heard of instances where an aircraft's wake has hit the runway surface and then bounced back up into the air, above the generating aircraft's flight path as it enters the flare. However, this is only likely to be an issue for a light piston driver following a little too closely behind a large jet.
Hey speaking of lousy JFK ILS13L, LGA ILS13, TEB no-go type days, today looks like one of them. Have wx/winds like this ever gotten so bad that EWR would be up and down RWY 11 only? I understand some jets (typically heavy) can work with 35ish kt crosswinds, however for most transport category aircraft, the max demo crosswind is around 30kts. I know BTA, one of your most frequent customers, can only work with 30ish as that's the max-demo xwind component on a E145. CAL's mainline jets can probably do 30-35, but I can't speak for Boeings.
Which brings me to another observation. Watching the Singapore heavy coming from Kuala Lumpur go around because of a conflict with a Rwy 11 Colgan arrival that took off 35 minutes ago makes me cringe my teeth every time it happens. Not fair but its just easier for the tower to have a 22L go around than the 11.
Regarding 500' separation with a VFR target and TCAS RA, here's what I can tell you (and btw, this is pretty much standard amongst all FAR121 airlines. I'd imagine foreign carriers abide by the same):
1. If given a TCAS corrective RA (i.e. CLIMB, CLIMB/DESCEND, DESCEND), we MUST comply with the command unless it would be considered UNSAFE to do so. Our manual warns us not to ignore a corrective RA when having an aircraft visually in sight, as the aircraft we're seeing may not be the aircraft generating the RA. Also, TCAS commanded climbs/descents MUST be handflown (autopilot reaction time too slow, as George is programmed to fly smoothly).
2. Generally speaking, a corrective RA will only be issued when the TCAS detects any sort of vertical converging (i.e. loss of vertical distance between a target) -- i.e one of the aircraft involved is climbing or descending at a rate which causes the TCAS to compute that a conflict is probable in under 30 seconds.
Simply passing a steady 400-500ft above/below a target will usually not trigger a corrective RA if both aircraft are steadily maintaining altitude. This may, however generate a preventive RA (ADJUST VERTICAL SPEED/MONITOR VERTICAL SPEED), in which our TCAS/vertical speed indicator will will light up red in the direction of the target (upwards if the target is above, downwards if below), telling us, hey, you've got someone minimally separated above/below you -- do NOT climb/descend (again, depending on whether the target is above or below). In this case, we're not likely to vacate our assigned altitude.
Last edited by Starscream; 12-01-2010 at 08:25 AM.
12-01-2010, 08:28 AM
#109
Gets Weekends Off
Joined APC: Mar 2010
Posts: 1,951
I think it's pretty common among ALL airlines SOP to always comply with an RA, even with the traffic in sight because you don't know if you're seeing the right one. This in the wake of some high profile accidents (PSA in SAN, Aeromex in LAX?)
12-01-2010, 08:28 AM
#110
Gets Weekends Off
Joined APC: Jan 2007
Position: Self employed
Posts: 3,048
This is a BS answer.
How long have you been in the agency? When TCAS was first being developed, an FAA flown B727, "N2" at the time, took controllers up for actual hands on demonstrations (late 1980's / very early 1990's). I sat on board at 4500 feet over the outer marker for RWY 28L/R at SFO, watching how it responded to inbound aircraft.
I absolutely know that I could find that you have received training in TCAS. You probably signed for it, too. Probably a few CBI's on it.
You don't even need to know everybody's SOP. Obviously, every pilot doesn't know every other pilots. Here's some actual guidance from YOUR agency:
U.S. Department InFO 08039
of Transportation DATE: 6/20/08
Federal Aviation
Administration Flight Standards Service
Washington, DC
Information for Operators (InFO)
Subject: Responding to a TCAS resolution advisory (RA) – Fly the RA
Purpose: To emphasize to managers, trainers, and pilots of airplanes equipped with TCAS II that a pilot should respond to an RA promptly as directed by the TCAS system, despite any contradictory visual cue or air traffic control (ATC) instruction, as required under ICAO PANS-OPS.
Discussion: This InFO stems in part from a mid-air collision of two airplanes over Uberlingen, Germany, that resulted when at least one of the pilots failed to respond promptly as directed by a TCAS RA. Fortunately, the importance of a prompt, appropriate response to a TCAS RA seems to be well understood among U.S. pilots. FAA guidance in AC 120-55, Air Carrier Operational Approval and Use of TCAS II, as revised, has contained the following since the early 1990s:
1) “Delayed crew response or reluctance of a flightcrew to adjust the aircraft’s flight path as advised by TCAS due to Air Traffic Control (ATC) clearance provisions, fear of later FAA scrutiny, or other factors could significantly decrease or negate the protection afforded by TCAS. Flightcrews are expected to respond to TCAS in accordance with the following guidelines when responding to alerts:
…
2) When an RA occurs, the PF [pilot flying] should respond immediately by direct attention to RA displays and maneuver as indicated …”
However, even among the most experienced pilots there are at least latent tendencies to believe what one sees with the naked eye and to follow an ATC instructions. These are dangerous human tendencies when flying in close proximity with other traffic. Those tendencies should be continually addressed in training in order to condition the desirable response in pilots, which is to fly the RA as first priority. In addition, to avoid confusion and workload permitting, a pilot should advise ATC when responding to a TCAS RA. When so advised, the controller will stop issuing instructions and allow the pilot to complete the TCAS maneuver. <<<---my note: did you get this training?
When the RA has been resolved, the pilot should inform ATC that the flight is returning to the last altitude/clearance issued by ATC.
Recommended Action: Managers, trainers, and pilots of airplanes equipped with TCAS II should collaborate to implement a sustained training message that is reinforced in all phases of pilot training and operations, including initial training, supervised operating experience, recurrent training, and line checks: Fly an RA promptly as directed by the TCAS system. That message is particularly effective when delivered in a flight simulator or in a flight training device, as recommended in FAA Advisory Circular 120-55B, in a scenario in which an ATC instruction conflicts with a TCAS RA.
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