November 28, 20214 yr Please have a look at the image below, a screen capture of the A320, and pay attention to the wind speed & direction, and the ground & air speeds. IMAGE The wind has been set to be full headwind, coming from 249°, which is exactly my current heading. Consequently I have 27 kts headwind and I would expect to see a difference of approximately 27 between the air speed and the ground speed (note the altitude is quite low, not in the high atmosphere where the air is very thin). Instead of this, the airspeed is 220 kts and the GS is 216, only 4 kts difference. This is not related to the aircraft, I also noticed this in another one. Did I miss something or is there something wrong? Any explanation is greatly welcome. Eric My Web Site
November 28, 20214 yr It will follow your True Air Speed (TAS), not your Indicated Air Speed. PC- AMD Ryzen 7800X3D, 64gb 6400mhz RAM, Nvidia RTX4090
November 28, 20214 yr What am I missing...? you are showing exactly 28 knots of headwind on the aircraft (GS=216, TAS=244) CPU: Core i5-6600K 4 core (3.5GHz) - overclock to 4.3 | RAM: (1066 MHz) 16GB MOBO: ASUS Z170 Pro | GeForce GTX 1070 8GB | MONITOR: 2560 X 1440 2K
November 28, 20214 yr Where you're making the mistake is assuming that the difference between TAS and IAS is negligible--far from it--in this case it's 24 knots (244 KTAS vs 220 KIAS). Your groundspeed is your TAS minus the headwind component (244-28) = 216 knots. Bob Scott | President and CEO, AVSIM Inc ATP Gulfstream II-III-IV-V Sys1 (MSFS20+24/XPlane12+11): AMD 9800X3D, water 2x240mm, MSI MPG X670E Carbon, 64GB GSkill 6000/30, nVidia RTX4090FE Alienware AW3821DW 38" 21:9 GSync, 2x4TB Crucial T705 PCIe5 + 2x2TB Samsung 990 SSD, EVGA 1000P2 PSU, 12.9" iPad Pro Thrustmaster TCA Boeing Yoke, TCA Airbus Sidestick, Twin TCA Airbus Throttle quads, PFC Cirrus Pedals, Coolermaster HAF932 case Sys2 (P3Dv5/v4): i9-13900KS, water 2x360mm, ASUS Z790 Hero, 32GB GSkill 7800MHz CAS36, ASUS RTX4090 Samsung 55" JS8500 4K TV@60Hz, 3x 2TB WD SN850X 1x 4TB Crucial P3 M.2 NVME SSD, EVGA 1600T2 PSU Fiber link to Yamaha RX-V467 Home Theater Receiver, Polk/Klipsch 6" bookshelf speakers, Polk 12" subwoofer, 12.9" iPad Pro PFC yoke/throttle quad/pedals with custom Hall sensor retrofit, Thermaltake View 71 case, Stream Deck XL button box Sys3 (DCS/P3Dv4/ATS/ETS): AMD 7800X3D, MSI MPG X870E Carbon, Noctua NH-D15S, 64GB GSkill 6000/30, EVGA RTX3090 Alienware AW3420DW 34" 21:9 GSync, Corsair HX1000i PSU, 4TB Crucial T705 PCIe5 + 2TB Samsung 970Evo Plus, TM TCA Officer Pack, Saitek combat pedals, TM Warthog, TM RS300 FF wheel/pedals, Coolermaster HAF XB case
November 28, 20214 yr Yup, look at the TAS and GS shown on your MFD / ND / whatever Airbus calls the map lol. Andrew Crowley
November 28, 20214 yr Apart from deducting headwind speed from IAS, IAS also shows lower than TAS the higher you fly due to the air being thinner. As a rule of thumb, I add 2% to the IAS for every 1,000 feet increase in altitude. E.g. IAS of 80 kts at 10,000 feet is circa. 96 kts. Ryzen 5800X3D, Nvidia RTX5080 - 32 Gig DDR4 RAM, 1TB & 2 TB NVME drives - Windows 11 64 bit MSFS 2024 Premium Deluxe Edition Resolution 2560 x 1440 (32 inch curved monitor)
November 28, 20214 yr Author Thanks for your replies, I understand I am confused between airspeed and TAS. I was comparing the airspeed with the GS to find the wind velocity, but I should compare GS and TAS instead. In that case, the difference is 28 kts, which is exactly the headwind speed. Thanks for correcting me, I now understand better. My Web Site
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