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#21
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747 cargo splits in two during takeoff!
On May 25, 10:15*pm, "Morgans" wrote:
*Google "balanced field" *and see what you find out. A balanced field is where the accelerate go and accelererate stop distances are equal. This produces a balanced V1. This will give you the minimum field length for a given wieght (It can also be calculated for an ATM or fixed derate). It does not give you the max takeoff wieght and not all airlines use it. From what I understand, it is a calculation done before every takeoff, and it has to do with how far and how fast they will be able to go down the runway, and still abort and get stopped on the runway, safely. This would be the accelerate stop distance. F Baum |
#22
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747 cargo splits in two during takeoff!
On Sun, 25 May 2008 18:39:21 -0700 (PDT), Tina
wrote: B, I can appreciate the 'go mode' from some speed onward, but runway lengths vary by some thousands of yards. With a typical load and normal conditions, how long a runway would allow you to decide to not go if something drastic happened at just below lift off speed (like a door blowing open, or a windscreen failing, something like that)? all australian airfields for Airline Transport use have published figures TORA TODA ASDA LDA tora - takeoff runway available toda - takeoff distance available asda - accelerate and stop distance available lda - landing distance available you can find what the aircraft requires from the equivalent of the POH and just compare the values. (it is a tad more complex but that is basically it) from dim memory asda assumes a stand on the brakes from V1. Stealth Pilot |
#23
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747 cargo splits in two during takeoff!
Stealth Pilot wrote in
: On Sun, 25 May 2008 18:39:21 -0700 (PDT), Tina wrote: B, I can appreciate the 'go mode' from some speed onward, but runway lengths vary by some thousands of yards. With a typical load and normal conditions, how long a runway would allow you to decide to not go if something drastic happened at just below lift off speed (like a door blowing open, or a windscreen failing, something like that)? all australian airfields for Airline Transport use have published figures TORA TODA ASDA LDA tora - takeoff runway available toda - takeoff distance available asda - accelerate and stop distance available lda - landing distance available you can find what the aircraft requires from the equivalent of the POH and just compare the values. Um, not exactly. We do have graphs, but I haven't even seen one in years. (I know whee they are if needs be,m though) Depending on the kind of operation and how close you get to limiting numbers, you can either use the figures from a quick reference handbook, often condensed into a booklet of flip cards you use for your speeds, (common for 737 type ops where all the runways are relatively long and the airplane usually light) or you have a set of tables, either in a big book or on computer, which you use to calculate the max takeoff for the runway and conditions and to give you the speeds for the takeoff in order to gauruntee you have accelerate-stop, climb performance and obstacle clearance as well as looking after some other odds and ends like tire speeds and brake energy limits, all capped by max structural of course. In addition we have a range of speeds that can be used. This is usually done for us, but in some airplane ops combinations, its best left up to the captain on the day to calculate. That gives us what you would call Vx or Vy in a light aircraft or somethng in between which would give us a good comprimise between a relatively short runway and a climb speed that would give a decent weight allowance for the climb. It's called improved climb performance (someone is going to pick me up on this with the more proper definition of improved climb, but if you read that statement carefully, you'll see it's correct) (it is a tad more complex but that is basically it) from dim memory asda assumes a stand on the brakes from V1. Actually, in a lot of airplanes nowadays you must do a rolling takeoff or you'll wreck the runway! Bertie Bertie |
#24
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747 cargo splits in two during takeoff!
So we'll blame it on the hysterical news media not knowing of what they
write. B "D Ramapriya" wrote in message ... On May 25, 7:20 pm, "BT" wrote: Talk about a miss representation of facts.. I merely typed out the CNN headline. snip Ramapriya |
#25
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747 cargo splits in two during takeoff!
Is the rolling start to protect the runway driven by exhaust gas
temperature effects on the runway surface? That has to be a silly questiion, it can't be related to the airplane weight, since the take off portion is also where they land, and they are not light on their toes! On May 26, 10:36 am, Bertie the Bunyip wrote: Stealth Pilot wrote : On Sun, 25 May 2008 18:39:21 -0700 (PDT), Tina wrote: B, I can appreciate the 'go mode' from some speed onward, but runway lengths vary by some thousands of yards. With a typical load and normal conditions, how long a runway would allow you to decide to not go if something drastic happened at just below lift off speed (like a door blowing open, or a windscreen failing, something like that)? all australian airfields for Airline Transport use have published figures TORA TODA ASDA LDA tora - takeoff runway available toda - takeoff distance available asda - accelerate and stop distance available lda - landing distance available you can find what the aircraft requires from the equivalent of the POH and just compare the values. Um, not exactly. We do have graphs, but I haven't even seen one in years. (I know whee they are if needs be,m though) Depending on the kind of operation and how close you get to limiting numbers, you can either use the figures from a quick reference handbook, often condensed into a booklet of flip cards you use for your speeds, (common for 737 type ops where all the runways are relatively long and the airplane usually light) or you have a set of tables, either in a big book or on computer, which you use to calculate the max takeoff for the runway and conditions and to give you the speeds for the takeoff in order to gauruntee you have accelerate-stop, climb performance and obstacle clearance as well as looking after some other odds and ends like tire speeds and brake energy limits, all capped by max structural of course. In addition we have a range of speeds that can be used. This is usually done for us, but in some airplane ops combinations, its best left up to the captain on the day to calculate. That gives us what you would call Vx or Vy in a light aircraft or somethng in between which would give us a good comprimise between a relatively short runway and a climb speed that would give a decent weight allowance for the climb. It's called improved climb performance (someone is going to pick me up on this with the more proper definition of improved climb, but if you read that statement carefully, you'll see it's correct) (it is a tad more complex but that is basically it) from dim memory asda assumes a stand on the brakes from V1. Actually, in a lot of airplanes nowadays you must do a rolling takeoff or you'll wreck the runway! Bertie Bertie |
#26
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747 cargo splits in two during takeoff!
Tina wrote in
: Is the rolling start to protect the runway driven by exhaust gas temperature effects on the runway surface? That has to be a silly questiion, it can't be related to the airplane weight, since the take off portion is also where they land, and they are not light on their toes! Yes, but we're not even supposed to do it on concrete runways which I've never understood. I've also had instructors tell me that sucking bits of the runway up in fornt of you is an issue which sounds pretty unlikely to me, and alos that the torsional load on the runway is an issue, which certainly seems possible when you see the damage braking and turning on the runway causes, but it's not really my department, i just do as I'm told! Bertie |
#27
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747 cargo splits in two during takeoff!
On May 26, 12:35 pm, Bertie the Bunyip wrote:
Tina wrote : Is the rolling start to protect the runway driven by exhaust gas temperature effects on the runway surface? That has to be a silly questiion, it can't be related to the airplane weight, since the take off portion is also where they land, and they are not light on their toes! Yes, but we're not even supposed to do it on concrete runways which I've never understood. I've also had instructors tell me that sucking bits of the runway up in fornt of you is an issue which sounds pretty unlikely to me, and alos that the torsional load on the runway is an issue, which certainly seems possible when you see the damage braking and turning on the runway causes, but it's not really my department, i just do as I'm told! Bertie Bertie, don't say things like you do as you're told in this news group. There will be some pretty inventive "I told you to's". Thanks for the information -- I guess FOD is a consideration, but some FO's, like birds, insist on being blended then cooked no matter what. |
#28
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747 cargo splits in two during takeoff!
Tina wrote in
: On May 26, 12:35 pm, Bertie the Bunyip wrote: Tina wrote innews:35a573d0-56f5-452a-abd8-37ddd3ccc956 @l42g2000hsc.googlegroups.c om: Is the rolling start to protect the runway driven by exhaust gas temperature effects on the runway surface? That has to be a silly questiion, it can't be related to the airplane weight, since the take off portion is also where they land, and they are not light on their toes! Yes, but we're not even supposed to do it on concrete runways which I've never understood. I've also had instructors tell me that sucking bits of the runway up in fornt of you is an issue which sounds pretty unlikely to me, and alos that the torsional load on the runway is an issue, which certainly seems possible when you see the damage braking and turning on the runway causes, but it's not really my department, i just do as I'm told! Bertie Bertie, don't say things like you do as you're told in this news group. There will be some pretty inventive "I told you to's". Well, this one is in the flight manual, so it's what we do. Thanks for the information -- I guess FOD is a consideration, but some FO's, like birds, insist on being blended then cooked no matter what. Well, it's not a big deal for little ones anyway. I have done full power on the brakes in things like 737s, but it's definitely not allowed in the A300 I used to fly and we don't do it in the 75 or 76 either. Bertie |
#29
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747 cargo splits in two during takeoff!
On May 26, 10:48*am, Bertie the Bunyip wrote:
Yes, but we're not even supposed to do it on concrete runways which I've never understood. I've also had instructors tell me that sucking bits of the runway up in fornt of you is an issue which sounds pretty unlikely to me, and alos that the torsional load on the runway is an issue, which certainly seems possible when you see the damage braking and turning on the runway causes, but it's not really my department, i just do as I'm told! Bertie Thanks for the information -- I guess FOD is a consideration, but some FO's, like birds, insist on being blended then cooked no matter what. Well, it's not a big deal for little ones anyway. I have done full power on the brakes in things like 737s, but it's definitely not allowed in the A300 I used to fly and we don't do it in the 75 or 76 either. Aside from the FOD the book also mentions Stall/Surge if you have an Xwind or Twind. This makes sense to me. The added TO distance is negligable anyways. Even for a static TO we only stand em up and then release the brakes and punch TOGA. Im like you man, they sign my check and if thats the ways they want it done,,,,,,,,,,,,, F Baum |
#30
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747 cargo splits in two during takeoff!
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