Present-day safety requirements necessitate the normal useof take-off performance figures which can give quite a falseimpression to the uninitiated.

For instance, and according to the textbook, the Ambassadorrequires a fifteen-hundred-yard runway if it is to take-offwith a full load. But this runway length presupposes anengine failure at safety speed and a consequent climb tofifty feet before reaching the airfield boundary.

By pre I.C.A.O. standards the runway length actuallyrequired is nine hundred yards — plus whatever distancethe pilot may have cared to add as a safety reserve.