The Chieftain isnt a real flash performer with an engine out, but with two people on board and full fuel it will fly away albeit not impressively. I'm curious as I'm sure we all are as to why this aircraft didnt.
I'm sure the accident at East Point, Darwin, last year is a good example of FAR 23 aircraft not performing well when away from STANDARD CONDITIONS, which is what they are certified under. As pointed out by other posters, these aircraft are certified when new and with test pilots doing the job.
It is not until you move onto FAR 25 design regs that PERFORMANCE, not control, is guaranteed.