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Old 22nd Aug 2008, 15:07
  #568 (permalink)  
xkoote
 
Join Date: Jul 2008
Location: Curacao
Age: 47
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Poeple please.....

Guys,

please do not take the "too little power for takeoff" and takeoff roll longer than normal" too litterally. The plane took off, became airborne and dropped back to the ground, all in less than the length of the runway. In other words a normal (near) MTOW takeoff. That's all.

Takeoff roll longer than normal makes absolutely no sense and depends on so many variables. Remember that by default, runway analysis is based on letting the plane roll and gain speed on the ground as much as possible before getting airborne. An MD-82 near MTOW and using a balanced runway concept on this giant runway would have used a LOT of runway. Rotating at 747 speeds of 160 knots. I can't stress this enough.

Too little power during the takeoff roll means that the crew would have aborted as soon as you see that the engine(s) are not delivering the thrust required by the speed card. So be carefull how things are translated.

Xander

EDIT: To try and make it clear what I mean, look at this video of an MD-83 departing Valencia, Venezuela in 0 wind conditions with an elevation of 1400' and a temperature around 28° Celsius. Almost similar conditions.
This particular model is a HGW MD-83 with a MTOW of 72.6 tons i.s.o. 67.8 tons. This flight would have been close to 70 tons that day. Even with a static takeoff, the takeoff roll was still more than 40 seconds long.
Would it have crashed if an engines was lost? No, because it is calculated that you can takeoff in such conditions and that weight and those speeds. Beleive me, these procedures are not guesstimates. Also you can see how little flaps is used on this takeoff. That's around 7° of flaps.

YouTube - Despegue MD83 Insel Air

Hear those Pratts roar ! ! ! God I love it.

Last edited by xkoote; 22nd Aug 2008 at 15:20.
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