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RAT 5
7th Feb 2011, 15:54
Greetings,
The QRH PI figures N738NG are causing me a question. Advisory landing distances include a temp correction +/-ISA. Makes sense as high temps = higher TAS = higher GS = longer distance. The NNC landing sidtances DO NOT include a temp correction. Why not? Physics & aerodynamics don't change with systems broken. Is this true for any other Boeing models? What am I missing?

Avenger
8th Feb 2011, 12:01
Without paraphrasing the entire QRH notes section: The Normal Configuration Landing Distance is already factored and is advisory for different runway surfaces and weights, as you correctly state, ISA deviations should be added to obtain the actual landing distances required for performance purposes.
The NNC landing distances relate to aircraft non-normal configuration and are based on configuration and "speed" hence the corrections for ISA deviations are not required.

RAT 5
8th Feb 2011, 22:07
Don't get that. I know about factoring. My simple brain says that the faster the G.S the longer the distance. Both tables use ISA for speed ref. Temp changes the TAS and therefore the G.S. in both cases.