It seems to me that in the USA they like to express the gradient in feet per nautical mile, as 200ft/NM.
I've only known minimum climb gradients expressed in percentages, as in 3.3% being the minimum standard.
From FAA's AIM link - Chapter 5. Air Traffic Procedures - Section 2. Departure Procedures:
http://www.faa.gov/air_traffic/publi...5/aim0502.html
Pilots must preplan to determine if the aircraft can meet the climb gradient (expressed in feet per nautical mile) required by the departure procedure, and be aware that flying at a higher than anticipated ground speed increases the climb rate requirement in feet per minute.
However, does this mean that we should all use GS, or just in the USA? Does procedures in the USA do not account for wind, and in other countries they do?
Or when a percentage is used, do you use IAS and not GS?
Too many variables... Googling it in the internet gives both IAS and GS, with no definitive answer.