As far as A A subjects, I always insisted on reviewing the performance theory i.e. FAR 25, and FAR 121. It often happens that while pilots are perfectly able to read a performance table or graph, the detailed knowledge of performance concepts is lacking...
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Personally, when I was flying, I made a difference between "hard limits", such as takeoff distances... i.e. runway length which is "physically limiting", and say a "second segment climb limit", which might be open airspace and in practice non existant obstacles...
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You will not crash if you pass the end of the runway at 25 feet AGL, although performance on takeoff is based on passing the end of the runway at 35 feet AGL... So... performance - Know the meaning of the numbers you read on tables and charts.
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Happy contrails