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View Full Version : long time low and slow in a 747 400


lynn789
6th Jun 2010, 06:45
it had been a long flight from JFK to sydney in a 747 400, I was a pax down the back so was happy that this model had the altered yaw damper so the tail no longer kicked around as it did on some of the early ones

we arrived at sydney early and were treated to what may have been a superb display of hand flying, all around the airport,waiting our turn to land with some sharp turns but hardly any flaps and the engines apparently set on flight idle all the time. we always traded height for airspeed, the views were spectacular and the wind dead calm. I never saw any runways we could have glided to if needed, and did wonder how far above stalling we were, and if we would have been safer with more speed and more flaps

exeng
6th Jun 2010, 07:02
I never saw any runways we could have glided to if needed

How many did you see on the ocean crossing?

and did wonder how far above stalling we were, and if we would have been safer with more speed and more flaps

We commercial pilots like to live life within a knot of our lives.

and the engines apparently set on flight idle all the time. we always traded height for airspeed

Next time I'll consider a descent with cruise power set so as to ensure I am well above stalling speed.


Regards
Exeng

bigduke6
6th Jun 2010, 09:31
At Flaps 1, you burn approx 5% more fuel than clean wing. Flaps 5 burn approx 12% more fuel (GE engines, not the RR most of QF has, but numbers should be similar).

Flying without flaps (at the appropriate speed), gives you as much margin, if not more, than flying at landing speed with landing flaps..........

Sounds like your crew was exercising good airmanship :ok:

Checkboard
6th Jun 2010, 09:33
Your delightful scenic tour of Sydney and its environs was courtesy of the local politicians. The areas under the runways at Sydney experience a little aircraft noise (nothing like the amount there was even 20 years ago!) and, after buying their houses complained to the politicians.

In a typical bit of politician logic, the politicians around Sydney promised to force the Civil Aviation Safety Authority to change the flight paths around the airport to "share the noise" between the "poor" areas (the houses with the high noise) and the "rich" areas (the houses in areas away from the flight paths).

This of course ignores the simple truth that it was NOT a decision to fly aircraft over poor areas - it is because those areas have some noise that the housing is cheap, and so poorer people can afford to live there!

In order to "share the noise", it is simply not possible to reduce the amount of noise in the busy areas (or the industry would simply do it anyway) - so we now have a procedure where we are forced to descend to low level, and fly around the city over the normally quiet areas so that they experience some of the noise which the necessarily noisy areas have. :rolleyes:

Sydney noise sharing policy :ugh: