Short field take off technique for big jets

[Ray Ban]

What's the technique used by jet airliners for take off from short runways? I'm curious as I watched a 727 take off from my home airport last weekend and I'm pretty sure it was airborne within about 4000ft - runway length is about one statute mile. I only fly light aircraft and I can't imagine airliners using ground effect to gather speed before zooming up!

Cheers.

[john_tullamarine]

... what sort of payload did the tri-motor have, though ? ... gets off quickly if it is light ...

[Ray Ban]

I have no idea about the payload but my question is generic. Say for example the aircraft has reasonable payload and performance data confirm that it is feasible to take off from a runway with length 5280'. Conditions are dry, runway is flat, temp in the mid teens and wind neglible. I presume they would use full power on the brakes, a higher flap setting than normal to get airborne earlier but at a lower speed and climb shallower than normal to allow speed to build up.

The actual 727 departure last Saturday was impressive!:cool:

[ferrydude]

Some time ago, I had the opportunity to watch a TACA 73-300 do a short/soft field takeoff from a grass covered clay levee. I was amazed how quickly she got off

[PAXboy]

RB, whilst not an aviator, I do know that the 727 is fabled for it's power. I understand that it is faster in the cruise than any other conventional jet. As I have heard, that includes those with a fourth donkey!

If operating from a field that is slightly short, they might well be weight limited. So they will not sell all the seats or carry more fuel than required. If they regularly operate into a field, then they will know the performance data to the last detail.

If it had arrived 'unexpectedly' then they might have chosen to leave with only crew and min fuel. Under those cicumstances, the 72 would be off the ground like lightning!

[Bokomoko]

RB,
All takeoff maneuvers - from short or long runways - are based on performance analyses and therefore all requirements must be adjusted accordingly. Obviously when departing from a short runway all “numbers” must be in accordance with such environment, usually lower weights and speeds, for instance. Depending on some circumstances there are some operating procedures, but nothing non-standard, and they can be different among airlines and airliners. Examples:
- Higher takeoff flaps setting (Procedure normally used for runway limited takeoff)
- Maximum takeoff power for current conditions instead of reduced or derated thrust
- No engine bleed for air conditioning and pressurization.
Bkmk