PPRuNe Forums - View Single Post - how to handle a rapid decompression over the Pacific ?
Old 19th Sep 2011, 18:57
  #50 (permalink)  
davidjh
 
Join Date: Dec 2004
Location: England
Posts: 66
Likes: 0
Received 0 Likes on 0 Posts
Descending at max speed

Quote: Question: Why does the descent have to be at max speed ? Why risk a structural overspeed instead of a low-speed stall ? Surely the RoD is more important to get down to 10,000' asap ?

e.g. A320 QRH Emer Descent : "Descend at the max appropriate speed."
e.g. B737NG FCTM Rapid Descent : "Target speed MMO/VMO".

Explanation appreciated.

Hi Reverse Flight
I hope that someone else has not already answered this, if so, I hope that mine is on a par with theirs.
With reference to ETOPS/EROPS, twins will be certified to x amount of minutes e.g. 120, 180 min etc. This then equates to a radius circle of x amount of nm drawn around their suitable/adequate en-route alternate aerodromes. This distance, if published, is normally base on a descent at a certain speed, normally max or high speed, followed by en-route at a certain speed using, for example, MCT if OEI. In other words, in order to achieve that distance, within the certified time, we would need to fly at the published speeds. Other than the above, there are the other concerns which have already been mentioned e.g. depressurization and need to descend to oxygen system limiting altitude etc. Hope that I have put my thoughts down correctly and that it helps.

Davidjh

Last edited by davidjh; 19th Sep 2011 at 19:21.
davidjh is offline