Old 15th Mar 2019, 04:45
  #199 (permalink)  
fdr
 
Join Date: Jun 2001
Posts: 547
The flow over the nose area is dependent on alpha and beta angles. A disagreement trigger value between AOA vanes can be set from test information and estimated fairly accurately by RANS or preferably DES type CFD to model the upwash changes. The mapped values could be used to correct in all cases as well. Vanes do fail, I paid for 2 in a couple of years with just one B737CL. Alternative sensing can be achieved by static vents and mapping, it is more reliable than the vane, but still can be affected adversely by contamination. slickest variant of those got out of sorts in Guam and cost the USAF a bundle in one smoking hole. Sensors fail, (how many of our cars have CELs on right now?)
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