LiveATC Discussion Forums
Air Traffic Monitoring => Aviation Audio Clips => Topic started by: david021 on April 02, 2009, 12:39:27 AM
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Today about 1PM, the BWI ATCT was evacuated and the fire department responded to a fire alarm in the tower..
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http://archive-server.liveatc.net/kbwi/KBWI-Twr-Apr-01-2009-1630Z.mp3
Here is the Clip..
Kinda interesting, because after they evacuated, airport operations told us that they were going over to the old us airways ramp tower. It sounds like they were using a portable radio.
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Been following this forum for a while now, time for me to contribute I think!
The first clip is from the KBWI TWR archives, combined from:
http://archive-server.liveatc.net/kbwi/KBWI-Twr-Apr-01-2009-1630Z.mp3
http://archive-server.liveatc.net/kbwi/KBWI-Twr-Apr-01-2009-1700Z.mp3
http://archive-server.liveatc.net/kbwi/KBWI-Twr-Apr-01-2009-1730Z.mp3
It begins about 1 minute before the announcement that the tower is going to be evacuated, then continues through the period when tower was unmanned, and ends as operations start getting back to normal. Silences have been edited out.
The second clip is from the KBWI BELAY archive, combined from:
http://archive-server.liveatc.net/kbwi/KBWI-BELAY-Apr-01-2009-1630Z.mp3
http://archive-server.liveatc.net/kbwi/KBWI-BELAY-Apr-01-2009-1700Z.mp3
http://archive-server.liveatc.net/kbwi/KBWI-BELAY-Apr-01-2009-1730Z.mp3
It follows Cape Air 921 (I think!) from initial contact with Approach, into the hold during the closure of KBWI, to the hand-off once the airport had reopened. It contains interesting exchanges whether the crew were prepared to continue into KBWI as an 'uncontrolled field', and updates on what was happening on the ground and how long the delay was likely to be. Transmissions from other aircraft and silences have been edited out.
Enjoy!
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Would Washington Center take over control of approach and Departures to/from KBWI?
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Would Washington Center take over control of approach and Departures to/from KBWI?
Potomac TRACON works that traffic already. They aren't co-located so that service would remain the same. The BWI tower would resume limited operations once they are established in the ramp tower.
I'm not familiar with their local procedures. I doubt the ramp tower has radar so the operations would be very limited to one in one out if that is the case.
w0x0f
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http://archive-server.liveatc.net/kbwi/KBWI-Twr-Apr-01-2009-1630Z.mp3
Here is the Clip..
Kinda interesting, because after they evacuated, airport operations told us that they were going over to the old us airways ramp tower. It sounds like they were using a portable radio.
Some interesting audio with Piedmont 4164 and the Southwest jet on approach (WN 50 if I heard correctly)
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tower ops remain the same...standard runway separation applies for tower controllers...potomac controllers use the bwi radar sensor which can track aircraft to within 1/2 mile from the runway...so operationally nothing would change once the controllers opened the temp tower.
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tower ops remain the same...standard runway separation applies for tower controllers...potomac controllers use the bwi radar sensor which can track aircraft to within 1/2 mile from the runway...so operationally nothing would change once the controllers opened the temp tower.
So the temp tower has radar?
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tower ops remain the same...standard runway separation applies for tower controllers...potomac controllers use the bwi radar sensor which can track aircraft to within 1/2 mile from the runway...so operationally nothing would change once the controllers opened the temp tower.
How is arrival information passed from the TRACON to the tower?
How is departure information passed from ZDC computer to BWI?
How are releases obtained by BWI from TRACON?
What type separation is BWI using if there is no radar display? Visual is very limited.
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tower ops remain the same...standard runway separation applies for tower controllers...potomac controllers use the bwi radar sensor which can track aircraft to within 1/2 mile from the runway...so operationally nothing would change once the controllers opened the temp tower.
How is arrival information passed from the TRACON to the tower?
How is departure information passed from ZDC computer to BWI?
How are releases obtained by BWI from TRACON?
What type separation is BWI using if there is no radar display? Visual is very limited.
Information can always be passed by telephone. There's usually a phone number that will ring directly at the position in the center or approach that you need to get a hold of. It's not as fast or convenient as a direct line, but it'll get the job done in a pinch. Though I'm sure operations slowed down quite a bit. Departure information doesn't get passed from the center to the tower. It goes the other way. Tower>TRACON>Center, and generally that is done automatically when plane "tags up" on the radar scope (in the tracon). If you mean clearance information the someone in the tower would probably call someone in the tracon with the time to relay the flight plans to the tower. As for separation: towers generally don't use their radar displays for separation unless the tower and a radar facility are combined up.
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Departure flight plan information starts at the ZDC Host Computer and is transmittion through the FDIO to the control tower. Once the aircraft departs, a departure message is sent back to the Center computer and the flight becomes "active" in the system, sending strips to other facilities as the aircraft flight along.
Without a certified radar scope, BWI would become a VFR Tower and probably would have to call for releases since they have no way to provide in-trail departure separation.
Arriving aircraft information is likely passed over the telephone if there isn't any other method available. The TRACON would be responsible for arrival/arrival separation (which they probably were before, anyway).
Between arrivals/departures, visual is pretty much their only option. If the weather was such where visual separation was impossible, the operation would slow down even more and coordination would increase between the radar room and tower.
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Without a certified radar scope, BWI would become a VFR Tower and probably would have to call for releases since they have no way to provide in-trail departure separation.
that's a good point. they probably have automatic releases under normal ops, but would be taken away.
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The point I was making was that tower ops would not remain the same. Flight data information is a major problem, not to mention the lack of radar.
Towers do use radar separation and have letters of agreement with their associated radar facility. Initial separation of departures is done with radar, so not having a radar display at the remote tower makes it a one in-one out facility.
So I guess my point is things are hardly normal under these circumstances as some here have said. That's all.
w0x0f
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i was sitting in the tracon...no it was not NORMAL ops as you would call it....but you don't need radar to work tower. you have runway separation and you have visual to give to departure...and any good tower controller would be hard pressed to give less than 3 miles to dept. you'd really have to launch, hold in position, launch...etc.
we did need rolling calls for departures since we weren't getting a scan ticket from tower.
so it was not normal, but it was far easier than you'd imagine. the only scramble was when the tower called and said we're OUT...but once they were established in the temp tower it was no biggie
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i was sitting in the tracon...no it was not NORMAL ops as you would call it....but you don't need radar to work tower. you have runway separation and you have visual to give to departure...and any good tower controller would be hard pressed to give less than 3 miles to dept. you'd really have to launch, hold in position, launch...etc.
It's pretty funny how someone who clearly has no tower experience can so easily make a statement qualifying a "good tower controller" as someone able to provide 3 miles initial departure separation from a temp tower without radar. A good tower controller could theoretically provide about 2 to 2 1/2 miles on successive departures easily, by hitting the CAT III SRS minimums each launch. Someone with tower experience would probably know this. Maybe you should ask your trainer about more specifics on tower ops - it'll only help you out in the long run.
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For another controller's narrative of a similar outage, see http://pinguinomalo.blogspot.com/2008/09/fling-poo-at-fan.html (http://pinguinomalo.blogspot.com/2008/09/fling-poo-at-fan.html)
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For another controller's narrative of a similar outage, see http://pinguinomalo.blogspot.com/2008/09/fling-poo-at-fan.html (http://pinguinomalo.blogspot.com/2008/09/fling-poo-at-fan.html)
That was an accurate description of how these things usually go. At least the several dozen that I have been personally involved with in my career. Hardly normal.
w0x0f
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...and any good tower controller would be hard pressed to give less than 3 miles to dept.
Huh? Perhaps you're not familiar with runways that much. In reality, you can launch aircraft as fast as the 6000' rule applies by saying "cleared for takeoff, cleared for takeoff, etc" and hand approach numerous airplanes 1.1 miles apart. (You'd be a real hit with approach controllers) You don't mention using radar/nonradar separation like headings. Visual separation only works for a while until planes go into the clouds or lose sight with each other. Losing the normal tools that we have changes the whole picture and way of doing business. No question.
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Huh? Perhaps you're not familiar with runways that much. In reality, you can launch aircraft as fast as the 6000' rule applies by saying "cleared for takeoff, cleared for takeoff, etc" and hand approach numerous airplanes 1.1 miles apart. (You'd be a real hit with approach controllers) You don't mention using radar/nonradar separation like headings. Visual separation only works for a while until planes go into the clouds or lose sight with each other. Losing the normal tools that we have changes the whole picture and way of doing business. No question.
Good point RV1. It's obvious that you actually have a good idea of tower ops and unlike mk, can speak with credibility on the subject. The only thing I would take exception with is your 1.1 mile in-trail for successive departures. You need to take into account the rate of acceleration of the departure. In other words, the first departure already has a velocity of let's say 150mph when you roll the second one (which has a velocity of 0). The 6000 feet SRS minimum will increase until the subsequent departure reaches the same velocity as the first one.
Maybe someone with a physics backgound could throw together a formula to calculate the distance required for the departure to accelerate to the same velocity as the first one. I tried but it's way beyond my ability.
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The only thing I would take exception with is your 1.1 mile in-trail for successive departures. You need to take into account the rate of acceleration of the departure. In other words, the first departure already has a velocity of let's say 150mph when you roll the second one (which has a velocity of 0). The 6000 feet SRS minimum will increase until the subsequent departure reaches the same velocity as the first one.
Maybe someone with a physics backgound could throw together a formula to calculate the distance required for the departure to accelerate to the same velocity as the first one. I tried but it's way beyond my ability.
A quick and dirty approximation (assuming that all planes have the same acceleration profile) takes the time between when the planes start rolling times the 250 knot speed limit... If you can tell me Vr and the l(ength) of runway to achieve Vr, you can compute a(cceleration) and t(ime):
Vr=a*t; l=a*t^2/2 => l=Vr*t/2 <=> t=2*l/Vr
Plugging in your numbers: t=2*1829(m)/67(m/s)=54.6(s) (*129(m/s) = 7022(m) separation@250kt)
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Maybe someone with a physics backgound could throw together a formula to calculate the distance required for the departure to accelerate to the same velocity as the first one. I tried but it's way beyond my ability.
Vf^2 = Vo^2 + 2a(Δx) where Vo = 0 (starts from rest) and a = V/t (or dv/dt for instantaneous velocity).
Therefore,
Δx = Vf^2 / 2a or
Δx = Vf^2 / 2(dv/dt)
In other words, divide the velocity squared by 2 times the acceleration to get that distance. Using the equation above is easier than using some of the other functions that depend solely on time. In this case, the only thing that functions on time is acceleration. I knew my edjamacashun would come in handy one day.
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A quick and dirty approximation (assuming that all planes have the same acceleration profile) takes the time between when the planes start rolling times the 250 knot speed limit... If you can tell me Vr and the l(ength) of runway to achieve Vr, you can compute a(cceleration) and t(ime):
Vr=a*t; l=a*t^2/2 => l=Vr*t/2 <=> t=2*l/Vr
Plugging in your numbers: t=2*1829(m)/67(m/s)=54.6(s) (*129(m/s) = 7022(m) separation@250kt)
Vf^2 = Vo^2 + 2a(Δx) where Vo = 0 (starts from rest) and a = V/t (or dv/dt for instantaneous velocity).
Therefore,
Δx = Vf^2 / 2a or
Δx = Vf^2 / 2(dv/dt)
In other words, divide the velocity squared by 2 times the acceleration to get that distance. Using the equation above is easier than using some of the other functions that depend solely on time. In this case, the only thing that functions on time is acceleration. I knew my edjamacashun would come in handy one day.
Man I wish I could do that.
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Uhhh.... what is... Greek??
Math and I are separated by more than 6,000 ft.
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my head hurts
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To be honest, I rough guessed the 1.1 part. I do have over 20 years controlling and I've been on the receiving end of someone launching a DC9 when the previous Cherokee was 2.5 miles from the runway, both on runway heading, and I'm not talking to the Cherokee yet! I have worked in VFR towers with and without RADAR/DBRITE. I have Center time and approach time as well.
I also try to stay in the shadows on most of these threads until something begs for a comment...
It is too bad I can't provide the tapes from about 1 year ago when I was the local and the radar controller combined and my supe was the fd/gc. I was clearing a plane to TIPH seconds after I cleared the previous a/c for takeoff, and then turned the a/c that I launched, BEFORE that one, away from runway heading, and then cleared the next for takeoff, then TIPH,... you get the point. Most pilots said little more than "Roger" and they'd do exactly what they were told. It was an awesome group of pilots, all flying g/a, the only aircarrier was the opposing team. Almost every one said "great job" or "excellent work" when they left. They really made the job FUN! This blows away simulators!
Ry length= 7001, vr=150, distance to vr=3600, time to vr=25 secs(roughly), interval for next plane=45 sec, roughly 90 airplanes per hour departure rate. A little high but can really mess with approach control! Stop departures.
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my head hurts
Mine too! :?
I think I'll stick to turning wrenches! 8-)
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Just scanning through the thread... BWI DOES have a radar. It's not a radar facility, but they do have a radar feed.
Justin
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Man I wish I could do that.
That's just the first semester of college level physics (mechanics). You get used to it after a while, like anything in life.
I forgot to add that the linear acceleration would have to be broken down into vertical and horizontal components to solve that equation I gave in my last post. A little trig and you're done. :-)
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i was sitting in the tracon...no it was not NORMAL ops as you would call it....but you don't need radar to work tower. you have runway separation and you have visual to give to departure...and any good tower controller would be hard pressed to give less than 3 miles to dept. you'd really have to launch, hold in position, launch...etc.
It's pretty funny how someone who clearly has no tower experience can so easily make a statement qualifying a "good tower controller" as someone able to provide 3 miles initial departure separation from a temp tower without radar. A good tower controller could theoretically provide about 2 to 2 1/2 miles on successive departures easily, by hitting the CAT III SRS minimums each launch. Someone with tower experience would probably know this. Maybe you should ask your trainer about more specifics on tower ops - it'll only help you out in the long run.
i guess i should have said it's hard giving 3 in trail when you're shooting 3 mile gaps between arrivals...BWI departs R10 and lands R33L for jets, 33R for smaller corp. aircraft and GA aircraft. obviously you can do less than that...DCA tower will launch 2 a/c in a 4 mile hole between arrivals...all on the same runway! with Visual sept on the 2nd dept. of course.
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Just scanning through the thread... BWI DOES have a radar. It's not a radar facility, but they do have a radar feed.
Justin
I think the point of this discussion was that BWI's tower was evacuated and they did not have a tower radar available from the temporary tower.