Under JAR it further states that the takeoff conditions must be such that a landing can be made in the event of a single forseeable failure. Thus if your aircraft is downgraded in the event of a failure (e.g a 737 is CatI after an engine failure) the takeoff conditions must be above THAT minima, or else a take-off alternate is required.
Last edited by Wizofoz; 12th September 2009 at 07:05.