Text in force at CS27-10: from CS27-1, effective 30 Nov 2007.
The take-off, with take-off power and rpm at the most critical center of gravity, and with weight from the maximum weight at sea-level to the weight for which take-off certification is requested for each altitude covered by this paragraph:
(a) May not require exceptional piloting skill or exceptionally favourable conditionsthroughout the ranges of altitude from standard sea-level conditions to the maximum altitude for which take-off and landing certification is requested, and
(b) Must be made in such a manner that a landing can be made safely at any point along the flight path if an engine fails. This must be demonstrated up to the maximum altitude for which take-off and landing certification is requested or 2134m (7,000 ft) density altitude, whichever is less.
ED Decision 2007/013/R · Source