I must say that some of what 747focal said has confused me particularly the "I can tell how noisy a plane is by looking at it" bit, however,
[paragraph relating to deleted posts removed - Checkboard]
747FOCAL - you wrote - "The old days of save your tires and brakes by landing at lower speeds at max flap are soon going to be failing the cost equation"
You are wrong in inferring that flap 30 is preferred on economic grounds. In fact the beancounters like it when pilots use Flap 25 for the following reasons:
- less flap wear and tear; &
- less fuel used; &
- the energy absorption characteristics of the carbon brakes on the 400 make it preferable to have a few high energy applications than frequent low energy ones i.e. using flap 25 you get better wear out of the brakes, particularly if used in conjunction with idle reverse.
In Qantas' case I believe the savings from Flap 25/idle reverse were a million (AUD) a year on brake pads alone.
I can't comment for the entire 400 community, but I don't see many manual landings with the autothrottle being used. As you correctly point out, any speed off bugged speed causes the autothrottle to 'hunt' which causes an annoying pitch up/down moment (when manually flying) that can throw you off profile easily. It is much easier to control the thrust manually when flying manually.
I am no great expert on noise abatement, but I would have thought takeoff would have been the more critical noise event?
As with anything, the final decision to use a particular flap setting rests with the pilot in command. The major considerations are aircraft weight, density altitude, wind, flap setting (25 or 30), full/idle reverse, visibility, landing distance available, slope and runway contamination. Also, a non-normal configuration may have an effect on landing flap setting. There may be others (e.g. visual/electronic approach slope guidance availability) I have left out.
Should these factors tally in favour of a flap 25 landing then that is probably what most would choose. Any noise policy would be considered AFTER the above factors had been taken into account. As an example, Jo-burg has a "we prefer idle reverse thrust on landing" clause on their noise pages in Jeppesen, but I don't know of many 400 pilots who use less than flap 30/full reverse on a hot day there given that JNB is a mile above sea level.
It certainly doesn't take much to push the equation in favour of flap 30 e.g. low visibility or contaminated runway, both common at LHR.
Safety is the primary consideration, then noise abatement. As it should be.
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[ 13 January 2002: Message edited by: Checkboard ]</p>