The maximum height for any drone is ordinarily 400ft. Some training providers have confused the issue by using the term altitude or elevation incorrectly. The graphic above shows you the difference.
Imagine a string 400ft long dangling vertically from the aircraft. If the end of the string cannot touch the ground then you are not compliant with the rules. Imagine a drone flying along the top horizontal line in the graphic from left to right, with the 400ft string touching the ground over the land, and then flying out to sea. The flight suddenly becomes non-compliant if the string cannot touch the surface of the sea. Altitude is not mentioned anywhere in the wording of this rule, only height. Height will change with the contours of the land and you must never let the drone climb above a height of 400ft without specific permission. A recent amendment also means that the 400ft string can be at any angle so you can descend down a slop as long as you are never more than 400ft away from the slope.
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