Welcome, Guest. Please login or register.
Did you miss your activation email?
September 16, 2014, 11:29:12 AM
Home Help Login Register      
News: LiveATC.net Flyers Released!  Please click here to download & print a copy and be sure to post at an airport near you!


+  LiveATC Discussion Forums
|-+  Air Traffic Monitoring
| |-+  Aviation Audio Clips (Moderators: dave, RonR)
| | |-+  Smoke in the BWI ATCT
« previous next »
Pages: 1 [2] Go Down Print
Author Topic: Smoke in the BWI ATCT  (Read 12130 times)
mkop
Newbie
*
Offline Offline

Posts: 29


« Reply #15 on: April 12, 2009, 05:03:16 AM »

For another controller's narrative of a similar outage, see http://pinguinomalo.blogspot.com/2008/09/fling-poo-at-fan.html
Logged
w0x0f
Sr. Member
****
Offline Offline

Posts: 322



« Reply #16 on: April 13, 2009, 02:07:04 PM »

For another controller's narrative of a similar outage, see 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
Logged
RV1
Full Member
***
Offline Offline

Posts: 104


« Reply #17 on: April 13, 2009, 02:58:04 PM »

...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.
Logged

Kick butt, take no names, they dont matter anyways
davolijj
Hero Member
*****
Offline Offline

Posts: 548


MMAC ARSR OKC


« Reply #18 on: April 13, 2009, 04:55:05 PM »

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.
Logged

Regards
JD
MathFox
Sr. Member
****
Offline Offline

Posts: 262


The Flying Fox


« Reply #19 on: April 13, 2009, 05:32:15 PM »

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)
Logged
Jason
Hero Member
*****
Offline Offline

Posts: 1260


CFI/CFII


« Reply #20 on: April 13, 2009, 05:45:12 PM »

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.
Logged
davolijj
Hero Member
*****
Offline Offline

Posts: 548


MMAC ARSR OKC


« Reply #21 on: April 13, 2009, 05:52:53 PM »

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.

Logged

Regards
JD
atcman23
Sr. Member
****
Offline Offline

Posts: 367



« Reply #22 on: April 13, 2009, 07:34:31 PM »

Uhhh.... what is... Greek??

Math and I are separated by more than 6,000 ft.
Logged

Mark Spencer
djmodifyd
Guest
« Reply #23 on: April 13, 2009, 08:52:35 PM »

my head hurts
Logged
RV1
Full Member
***
Offline Offline

Posts: 104


« Reply #24 on: April 13, 2009, 09:29:54 PM »

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.
Logged

Kick butt, take no names, they dont matter anyways
joeyb747
Hero Member
*****
Offline Offline

Posts: 1583


Nothing Like A 747!


« Reply #25 on: April 13, 2009, 10:17:28 PM »

my head hurts

Mine too!  huh

I think I'll stick to turning wrenches!  cool
Logged

Aircraft Mechanic
J-Mart
Newbie
*
Offline Offline

Posts: 9


WWW
« Reply #26 on: April 14, 2009, 10:19:46 AM »

Just scanning through the thread... BWI DOES have a radar. It's not a radar facility, but they do have a radar feed.

Justin
Logged

Justin A. Martin
Jason
Hero Member
*****
Offline Offline

Posts: 1260


CFI/CFII


« Reply #27 on: April 14, 2009, 11:17:07 AM »

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.  smiley
Logged
mk
Jr. Member
**
Offline Offline

Posts: 94



« Reply #28 on: April 14, 2009, 11:26:32 AM »

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.
Logged
jmcmanna
Newbie
*
Offline Offline

Posts: 36


« Reply #29 on: April 14, 2009, 12:14:01 PM »

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.
Logged
Pages: 1 [2] Go Up Print 
« previous next »
Jump to:  


Login with username, password and session length

Powered by MySQL Powered by PHP Powered by SMF 1.1.19 | SMF © 2011, Simple Machines Valid XHTML 1.0! Valid CSS!