Brussels - rwh 20 for take offs
Join Date: Nov 2004
Location: bruusels
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This is a nice topic i would like to take part.I am working at EBBR airport and i live in the past of RWY 25R!!
And i can tell you that aircraft over my head are making less noise
than the "tramway"crossing along my street.My sealing is shaking and will soon collapse with that tram.
If aircraft are making so much noise ,i don't understand why people are almost fighting to get a land at Steenokerzeel,Diegem?and Zaventem to build their house.
People living in the area of the airport had good prices for their house,and what about the "anti-noise wall" that has been built?
So,i really wonder what push people to live there knowing they have an airport nearby...just my 2 cents
tgdxb
Is my understanding then right that the altitude of the overflying B747 could have been higher with more engine power at T.O.
Without knowing the takeoff weight of the aircraft, its hard to know if the aircraft was heavy and using full takeoff power or light and using derated thrust.
Is it right that a 15 deg climb rate still is reasonable for a B747?
Don’t confuse angle of attack with climb angle. 8-10% is a more reasonable climb angle for a heavy 747. Using that figure, at 5000 meters, you could expect the aircraft to be at a height of 400-500 meters.
One more question - you suggest a rotate at about 3/4 down the rwy. Now does this mean that the longer the runway the longer - potentially - the speed at which you rotate? And maybe the higher the climb rate?
Generally speaking the length of the runway doesn’t impact the rotation speed. For a 300,000 kgs aircraft you will use the same V-speeds for a 10,000 ft or 15,000 ft runway. However, the longer runway does offer more flexibility, it is possible to use a reduced takeoff thrust rating or increase the V-speed on the runway to get a higher climb rate. This is airline specific, we will reduce thrust but don’t use the higher V-speed method on the -400.
You must understand that we WANT to use ALL of the runway, we have the ability to takeoff with approx 65% of the available takeoff power in the -400 depending on the aircraft weight runway combination. That thrust reduction dramatically reduces our engine costs as the engine is able to operate at lower temperatures. This is perfectly legal and safe.
Without knowing the airline and their procedures, its extremely difficult to give accurate answers, there are many ways to operate the same type of aircraft. For example, there is a noise monitor right off the end of RWY20, this airline may have decided that using reduced takeoff thrust would create a lower noise footprint and hopefully not trigger the noise monitor!
Mutt.
Is my understanding then right that the altitude of the overflying B747 could have been higher with more engine power at T.O.
Without knowing the takeoff weight of the aircraft, its hard to know if the aircraft was heavy and using full takeoff power or light and using derated thrust.
Is it right that a 15 deg climb rate still is reasonable for a B747?
Don’t confuse angle of attack with climb angle. 8-10% is a more reasonable climb angle for a heavy 747. Using that figure, at 5000 meters, you could expect the aircraft to be at a height of 400-500 meters.
One more question - you suggest a rotate at about 3/4 down the rwy. Now does this mean that the longer the runway the longer - potentially - the speed at which you rotate? And maybe the higher the climb rate?
Generally speaking the length of the runway doesn’t impact the rotation speed. For a 300,000 kgs aircraft you will use the same V-speeds for a 10,000 ft or 15,000 ft runway. However, the longer runway does offer more flexibility, it is possible to use a reduced takeoff thrust rating or increase the V-speed on the runway to get a higher climb rate. This is airline specific, we will reduce thrust but don’t use the higher V-speed method on the -400.
You must understand that we WANT to use ALL of the runway, we have the ability to takeoff with approx 65% of the available takeoff power in the -400 depending on the aircraft weight runway combination. That thrust reduction dramatically reduces our engine costs as the engine is able to operate at lower temperatures. This is perfectly legal and safe.
Without knowing the airline and their procedures, its extremely difficult to give accurate answers, there are many ways to operate the same type of aircraft. For example, there is a noise monitor right off the end of RWY20, this airline may have decided that using reduced takeoff thrust would create a lower noise footprint and hopefully not trigger the noise monitor!
Mutt.
