Originally Posted by
lucaberta
that is a good question. Over here in Europe there are no strict regulations that force 250kts below 10,000', as far as I know (at least here in Italy), but in the USA no controller can issue deviation from an FAR which specifically says that every aircraft *must* be flying slower than 250kts below 10,000'.
I would be curious to know if you really keep the leading edge flaps out until 10,000' during climb when you're in the USA.
Ciao, Luca
Guppy's comments are directly relevant to the US where there is a hard 250 knot limit, UNLESS MINIMUM SAFE AIRSPEED dictates otherwise. There is then a list of aircraft to which this is likely to apply. Which I believe includes Guppy's 747. In the case of the FAA they do not define minimum safe airspeed as the minimum you can climb dirty, it is a clean climb configuration with sensible safety margin (can't seem to find the exact detail )