What if buffet boundary limit, high, low and its' causes?

081 Principles of Flight aka Aerodynamics or POF (Aeroplane)
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What if buffet boundary limit, high, low and its' causes?

Postby CaptainMFT » 18 Jun 2016 00:59

Buffet Boundary Limit :-
The buffet boundary has each low and high speed limits The low speed buffet boundary marks the onset of the pre-stall buffet at a tenth (10th) margin higher than VS and therefore the high speed buffet boundary marks the onset of mach related buffet, usually MMO or occasionally slightly below that. 

At height the 2 speeds close together to become the "coffin corner" since you cannot fly faster or slower and you'd either stall or hit MMO. Increased load factor reduces each the buffet margins and also the maximum altitude. 

1.3g boundary charts equates to moderate turbulence or a forty (40o) deg bank level turn. 
1.6g boundary charts equates to severe turbulence or a fifty (50) deg bank level turn. 

The margins between the airplane and therefore the low and high speed buffet are reduced by: 
- Heavy airplane weight. 
- High altitude. 
- High load factor .
- Forward CG position (which will increase the stall speed) .
The buffet boundary and also the margins between low speed and high speed buffets are shown on the speed tape of the EFIS PFD as a yellow margin for 1.3g buffet boundary and by black and red squares for a 1.0g limit.

Good luck,

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