So you want green? Well you have to strangle a few greenies, get rid of a few governments and put in some clever computer systems. Here's why.
1. Have a start up time that means no waiting at the runway.
2. A short taxi journey to nearest runway with minimal backtracking or optimum intersection.
3. Optimum powered takeoffs (probably full welly and full climb thrust - sod the noise).
4. An immediate turn (allowing for terrain) direct to a three mile final at destination with no wind or a computer optimised track to optimise/mitigate winds along track.
5. An un-interupted climb straight to optimum level.
6. An un-interupted descent.
7. A landing on the nearest runway to the parking stand.
8. Operationally, fly with minimum fuel.
9. Fly always at optimum speeds.
10. Have lightest seats, minimum catering, minimum spare magazines, safety cards, toilet rolls, blankets, rubbish etc.
11. Have clean holds, no rubbish.
12. Have clean wings, engines (compressors washes etc.)
13. Have good seals on all doors.
14. Have GPUs/FEPs/ACs at all ground stations.
15. Fly fully loaded.
And do you know what, we try to do all of the above except for 3 and 9. Both cost too much - it is cheaper to burn the fuel than pay for maintenance. Governmental and Local procedures, jobsworths, greenies, other buggers flying, 'elf'n'safetee etc. all put the mockers on the rest.
PM