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Hawk777th

Correct no bleed takeoff?

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BASIC VERSION Before line up, ISO valve close, #1ENG Bleed off, APU Bleed on, #2ENG Bleed off. APU provides air conditioning/pressurization through the L Pack. After takeoff, reverse your actions.


Matt Cee

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Engine bleeds can be shut in order to increase preformance (Air is not "stolen" from the engines any longer). The correct procedure for this should be in the QRH or FCOM (or use the above). In any normal situation you'd have engine bleeds on, APU shut off (and not bleeding, ofc), packs and Isolation Valve to Auto. Resiric fans can be as you like, but with them off, the air would be rather nasty after a short while. I know that some pilots prefer these off during ground ops and even take offs, because they're so noisy. Taking off without engine bleeds is basically only done on fields with short runways, high temperatures and/or high elevation.


Magnus Meese

NGX Pilot

VATSIM C1, SUP and Pilot

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737 crews refer to it as a no-bleeds takeoff. Packs remain on and are fed bleed air from the apu. However, I´ve witnessed something once on a Varig 777 which was refered to by the crew as a "packs-off takeoff". Instead of closing the engine´s bleed air valves and using the apu for pressurization during the first segment, they simply shutoff the packs when ligning up with the rwy and they also left the apu off. The engine bleeds were left in auto (something you can´t do in an NG). In reality it´s the same thing, no matter how you call it. In both cases you gain a extra few thosand pounds of MTOW.


Cheers,
Victor M. Lima
 

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Engine bleeds can be shut in order to increase preformance (Air is not "stolen" from the engines any longer). The correct procedure for this should be in the QRH or FCOM (or use the above). In any normal situation you'd have engine bleeds on, APU shut off (and not bleeding, ofc), packs and Isolation Valve to Auto. Resiric fans can be as you like, but with them off, the air would be rather nasty after a short while. I know that some pilots prefer these off during ground ops and even take offs, because they're so noisy. Taking off without engine bleeds is basically only done on fields with short runways, high temperatures and/or high elevation.
Thats why I needed it thanks!

A Walker

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