PPRuNe Forums - View Single Post - Air Asia Indonesia Lost Contact from Surabaya to Singapore
Old 28th Dec 2014, 08:34
  #79 (permalink)  
cdeanda
 
Join Date: Nov 2006
Location: Mexico/Singapore
Posts: 3
Real winds and some speed calculations

To clarify the winds question here's a cropped pic of the winds aloft chart for FL340 on Dec 28th, 00Z.:



If both the ATC Radar and the L&T sheet pictures are true, using a speed calculator we can get the following info:
GS: 353 kts
Average Tailwind according to the chart: 20 kts
TAS at 36,300ft: 333 kts
Computed MACH: 0.58
Computed equivalent airspeed: 180 kts

Now, from the A320 QRH with an actual TOW of 63.6T the calculated Green Dot speed would be around 223 kts at that altitude (The corresponding VLS and V alpha prot would be quite close to that number).

All these numbers are just a rough guess using ISA Standard conditions (Usually in this part of the World we have ISA +10 to +15 at cruise FLs)
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