A320 Emer descent.

[vilas]

Hi guys
A320 has a new procedure for EMER DESC. In that with damage lowering of gear is suggested. But I checked two different company QRH. One says below 25000ft consider, the other doesn't mention this limitation it just says Consider lowering gear. Any one has anything official from airbus?

[sierra_mike]

nothing official i can provide you. thought the 25000ft limitation for the gear is long gone. all our current QRH just state "CONSIDER L/G EXTENSION"
the "CONSIDER L/G EXTENSION" line has no extra indent hence doesn't depend on the damage suspected precondition above as i understood.

[compressor stall]

We have pure Airbus SOP and as above there is no altitude restriction for gear extension.

[vilas]

Thanks! The doubt arose because one airline with March 2017 update has the limitation and the other with April 2017 doesn't have.

[compressor stall]

My update is 17 Mar 17.

[mcdhu]

If you apply the Landing Gear lowering IAS and Mach No limits, you would be pressed to lower the gear above FL250. Thus AI removed the altitude restriction.

[vilas]

mcdhu
Starting from FL350 with damage for lowering gear which speed restriction will you observe .6M or 250 kts? I think it should be .6M or is it? so considering low speed buffet with the aircraft turning it would have be some altitude where you would reduce to .6M. So the altitude restriction may have been for that reason. Any thoughts welcome.

[mcdhu]

Thanks Vilas. I enjoy reading your inputs -you clearly have great knowledge of the Airbus (much better than mine!)

I suppose you would obey which of the 2 restrictions was most limiting.
Eg If you were cruising high and had 240KCAS and M0.77, you could not lower the gear. Without getting my redundant CRP5 out, I guess to get below M0.60 you would have somewhere around 190KCAS - unlikely.
It might be interesting to calculate where M0.60 crosses with 250KCAS. Somewhere around 25,000’ I guess.
How academic can we get?

[vilas]

mcdhu
The altitude restriction of FL250 for lowering landing gear did not appear very logical. So airbus removed the altitude restriction and introduced .6M restriction (previously it was only 250kt), which is more appropriate. It's effectively almost same because when with damage if you reduce speed to 250kts. it will become .6M at appx. FL250.