150KTS = 2.5NM/min
Conversion NM to feet: 2.5NM/min x 6080 = 15200 ft/min
6% x 15200ft/min = 920ft/min (or just GS x 6 = 900ft/min)
Rule of thumb: GS x 5 = ROC/ROD for a 3° path (3° = 5%)
For a 4° path just calculate for a 3° path, (GS x 5), devide by 3 and multiply with 4
In your instrument approach example it should be 750ft/min instead of 450 ft/min for a 3° glidepath at 150KTS (GS x 5)
Minimum climb gradient on SID charts are shown in %. Just multiply this number with your groundspeed and you have your min. ROC
Last edited by torob; 18th June 2011 at 21:12.