January 8, 20233 yr Ok I know the rules of thumb when the glide slope is a standard 3 degrees. but what’s the actual formula when the glide slope is say 6.49 degrees at Aspen (KASE)? Ciao!
January 8, 20233 yr Jeppesen approach plates place a ROD table right on the approach plate when there's a non-standard glidepath angle. Otherwise you can multiply the GP angle by your groundspeed in nm/min and add a couple zeroes...so for 6.49 deg at 120 knots (2 nm/min) it's ~6.5 x 2 x 100 = 1300 fpm, at 180 it's 6.5 x 3 x 100 = 1950 fpm, and at 150 it's halfway between those two, or ~1625 fpm. By comparing the 120 knot and 150 knot figures, I see that a 30-knot increase results in a 325 fpm increase, or around 110 fpm per 10 knots of airspeed. So a GS of 110 knots would be 1300 - 110 = 1190 fpm. That's for a quick in-your-head wag...if you have a calculator handy, it's simple -- GP angle x groundspeed / 0.6 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
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