Balanced field length eh??
Balanced field length eh??
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Here`s what a certain airline does........
– the T/O includes clearway and on a wet rwy, can you believe it they only work on a 15 ft screen ht at the end of this! We do what they call improved clb t/o’s to get more weight off a certain rwy and to meet second segment clb requirements. We accelerate to a higher gnd speed on the rwy and then lift off “late” where there are no immediate obstacles ( 1st segment clb ) – then once airborne we already have the energy to meet 2nd segment clb ! – Clever ?
– the T/O includes clearway and on a wet rwy, can you believe it they only work on a 15 ft screen ht at the end of this! We do what they call improved clb t/o’s to get more weight off a certain rwy and to meet second segment clb requirements. We accelerate to a higher gnd speed on the rwy and then lift off “late” where there are no immediate obstacles ( 1st segment clb ) – then once airborne we already have the energy to meet 2nd segment clb ! – Clever ?
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Bigman
Sounds OK. You reject the T/O at V1 so anything beyond that is going into the air with you anyhow. The fact that you have a little more energy and are initially climbing at V2+20 rather than V2+10 (for arguments sake.) only makes things easier to satisfy second segment climb requirements. As long as it's within tyre speed limits I see no problem.
Anyone?
Sounds OK. You reject the T/O at V1 so anything beyond that is going into the air with you anyhow. The fact that you have a little more energy and are initially climbing at V2+20 rather than V2+10 (for arguments sake.) only makes things easier to satisfy second segment climb requirements. As long as it's within tyre speed limits I see no problem.
Anyone?
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Im with you on that one SRT, only the tyre speed to worry about. You can never say its a bad thing to be getting air with a little spare change in your pocket...
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WRT. THE SCFREEN HEIGHT OF 15 FOOT ON A WET RUNWAY, THIS IS NOT AN AIRLINE SPECIFIC THING. MOST AIRLINERS WILL NOT BE ABLE TO REACH A SCREEN HEIGHT OF 35' ON A WET RUNWAY, SO (GET THIS) THE CERTIFICATION REQUIREMENTS SPECIFY THAT WHEN THE CONDITIONS ARE WORSE THAN NORMAL, YOU CAN REDUCE THE TAKE OFF LIMITATIONS TO ENSURE THAT THE AIRCRAFT CAN GO.
MY QUESTION IS THEN, WHY CANT YOU WORK TO A SCREEN HEIGHT OF 15' ON A DRY RUNWAY? THAT WAY, YOU WOULD BE ABLE TO GET INTO THE AIR WITH MORE WEIGHT AND MAKE MORE MONEY
MY QUESTION IS THEN, WHY CANT YOU WORK TO A SCREEN HEIGHT OF 15' ON A DRY RUNWAY? THAT WAY, YOU WOULD BE ABLE TO GET INTO THE AIR WITH MORE WEIGHT AND MAKE MORE MONEY
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SRT,
Agreed also. Looks like it's airborne anyway and probably has a high airspeed. That is what counts at the end of the strip.
The numbers on the day in question always determine whether it is safe or not (and legal).
Mind you, the stopping distances quoted were always an act of blind faith in Mr Boeing for me.
old take-off doubter.
Agreed also. Looks like it's airborne anyway and probably has a high airspeed. That is what counts at the end of the strip.
The numbers on the day in question always determine whether it is safe or not (and legal).
Mind you, the stopping distances quoted were always an act of blind faith in Mr Boeing for me.
old take-off doubter.
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Saw a similar picture from the sharp end once, only a little C210 mind you, taking off outa Francistown in Bots. 
Prop went overfine and I was sweating.. pulled her off and could already see where the crash was to take place - luckily stayed up..
For a while there, was the world's fastest trycicle, I was..
R
Prop went overfine and I was sweating.. pulled her off and could already see where the crash was to take place - luckily stayed up..
For a while there, was the world's fastest trycicle, I was..
R
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I'd just like to make a couple of points,
1. The increased V2 climb technique is used to maximise the performance of the aircraft when the climb limited mass is more restrictive than the field length limited mass, using an inceased V2 will allow an increase in Take Off mass and the aircraft will still meet the field length limited mass requirements (as speed increases you get closer to Vmd which is where Thrust minus Drag is a maximum and therefore gives you Vx the best gradient of climb speed). Whatever happens you must still meet the JAR min requirements of 2.4%(2 eng) or 3.0(4 eng)
2. As to the question of 15 feet screen heights vice 35 feet screen heights in wet conditions it is full explained in JAR 25 AMJ25X1591 this reads as
".....for 1 engine inoperative.....the take off distance required on a wet runway is the distance from brakes release point to the point at which the aeroplane is 15 feet above the runway, consistent with the achievement of V2 before reaching 35 feet, assuming the critical engine fails at Vef corresponding to Vgo(V1) for all the rest of the wet runway requirements with all engines operating the aircraft must meet the 35 feet screen height....."
That is all theoretical and in the JAR, what really matters is flying safe and not taking chances, don't let companies push you to ignore performance calculations for an extra 2 tonnes of freight for the bosses to drink more champers on the back of overworked and underpaid crews
1. The increased V2 climb technique is used to maximise the performance of the aircraft when the climb limited mass is more restrictive than the field length limited mass, using an inceased V2 will allow an increase in Take Off mass and the aircraft will still meet the field length limited mass requirements (as speed increases you get closer to Vmd which is where Thrust minus Drag is a maximum and therefore gives you Vx the best gradient of climb speed). Whatever happens you must still meet the JAR min requirements of 2.4%(2 eng) or 3.0(4 eng)
2. As to the question of 15 feet screen heights vice 35 feet screen heights in wet conditions it is full explained in JAR 25 AMJ25X1591 this reads as
".....for 1 engine inoperative.....the take off distance required on a wet runway is the distance from brakes release point to the point at which the aeroplane is 15 feet above the runway, consistent with the achievement of V2 before reaching 35 feet, assuming the critical engine fails at Vef corresponding to Vgo(V1) for all the rest of the wet runway requirements with all engines operating the aircraft must meet the 35 feet screen height....."
That is all theoretical and in the JAR, what really matters is flying safe and not taking chances, don't let companies push you to ignore performance calculations for an extra 2 tonnes of freight for the bosses to drink more champers on the back of overworked and underpaid crews
