Originally Posted by Gulfcapt
De facto, given that the 400'AGL is a certification requirement (as opposed to an operating requirement) from US FAA, I guess it would depend on whether a given country has their own certification standard or not. You certainly raise an interesting point; maybe somebody else can answer it for us.
The operating requirement (in many countries, the country is that of the operator) is that take-off obstacle clearance must be shown on the basis of the OEI net flight path data provided in the Airplane Flight Manual.
The performance data in the AFM are established in accordance with the airworthiness certification regulations, which specify that the OEI net take-off flight data must be based on a procedure which assumes that the take-off flap setting is maintained up to at least 400 ft above the runway altitude.
To my knowledge, all large transport airplanes manufactured in what used to be called the "western" world, are certificated to essentially the same standards as FAR Part 25 or CS-25.
regards,
HN39