PPRuNe Forums - View Single Post - AF 447 Thread No. 5
View Single Post
Old 9th Jul 2011, 23:56
  #19 (permalink)  
Graybeard
 
Join Date: Nov 2006
Location: SoCalif
Posts: 896
Likes: 0
Received 0 Likes on 0 Posts
Static (from last page of thread 4)

HN39:
Agreed, and everybody seems to think of the pitots misreading at high AoA, forgetting that airspeed is derived from the difference between two pressures: pitot and static. Sometime ago someone posted a drawing showing the static ports on the bottom of the front fuselage. At these AoA's the misreading of the static pressures may be more important than that of the pitot pressures. EDIT:: Particularly when "The airplane was subject to roll oscillations that sometimes reached 40 degrees" (Thx to an anonymous reader of the thread).
Thanks also to A337 for the refresher pix of the static ports.

The A330 has an apparent up to 300 ft static port correction at low airspeeds. This is not unusual, but at a greater AOA than stall warning, the static pressure is sure to increase to the point the static ports nearly become pitot ports.

Rather than, "What's it doing now?", the more I read the more I question, Why did they design it that way?"
Graybeard is offline