BA 747-400 APPROACH AT LHR
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747MAN
Maybe you refer to the practice of using Flap 25 as the usual land flap setting, rather than Flap 30, when there are no performance reasons that require the use of Flap 30?
This would result in lower noise levels, when compared to an operator using Flap 30 at a given weight.
Maybe you refer to the practice of using Flap 25 as the usual land flap setting, rather than Flap 30, when there are no performance reasons that require the use of Flap 30?
This would result in lower noise levels, when compared to an operator using Flap 30 at a given weight.
Flap 25 is also useful to get onto the 1st tee quicker.
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For normal situations that is true. For a variety of non-normal situations you have to use flap 25. One example is whenever Vref is above 167 KIAS (overweight landing) flap 25 must be used to avoid the possibility of flap relief operating. Flap 30 Max KIAS is 180.
Flap 25 still remains approved for a normal landing and is still used by Qantas on some occasions.
Flap 25 still remains approved for a normal landing and is still used by Qantas on some occasions.
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Think of the noise you generate operating an aircraft like water filling a glass. Well with the new monitor schemes they are coming up with that start in April each airline will get their "glass" and once full you aren't operating at that airport till you get your glass next year. 
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10%???? Nope. maybe 5.5 - 7%..... So how are those CDA procedures treating you over there anyway?
My takeoff stuff is almost ready as well. estimated Vlof of 747-400 at 875,000 lbs is approx 200+ kts. And then there is thrust management..... That your really gonna love.
My takeoff stuff is almost ready as well. estimated Vlof of 747-400 at 875,000 lbs is approx 200+ kts. And then there is thrust management..... That your really gonna love.
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Hi Mutt. I don't think they are adding any new monitors. K**** M***** and crew are just gaining more faith in their ability to accurately measure operational noise and start handing out infractions and gathering fuduciary evidence that could be used legally.
If you understand the noise game, which I assume you do, you know that the what, how and when is all over the board. 747s being the tent pole aircraft, well besides the 727s are going to continually get more and more attention. I was suggesting that the operators should do everything that can be safely done to get as much shine off there butt before it gets really hot. I can't tell you who I am and what I do, but trust me, I can see things coming that G** R****** and crew are bringing that is gonna kill some of the little operators and badly hurt the big ones.
Can you believe that there will actually still be non re engine 727s still flying in and out of LHR after April 1 this year? Some have my hushkit on them thanks to Article 84.
Sorry decided to get rid of the regulators names yest they get attacked.
[ 09 January 2002: Message edited by: 747FOCAL ]
[ 09 January 2002: Message edited by: 747FOCAL ]</p>
If you understand the noise game, which I assume you do, you know that the what, how and when is all over the board. 747s being the tent pole aircraft, well besides the 727s are going to continually get more and more attention. I was suggesting that the operators should do everything that can be safely done to get as much shine off there butt before it gets really hot. I can't tell you who I am and what I do, but trust me, I can see things coming that G** R****** and crew are bringing that is gonna kill some of the little operators and badly hurt the big ones.
Can you believe that there will actually still be non re engine 727s still flying in and out of LHR after April 1 this year? Some have my hushkit on them thanks to Article 84.
Sorry decided to get rid of the regulators names yest they get attacked.
[ 09 January 2002: Message edited by: 747FOCAL ]
[ 09 January 2002: Message edited by: 747FOCAL ]</p>
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747FOCAL
I unfortunately have to understand the noise game, but I haven’t got a clue as to what you are talking about <img src="smile.gif" border="0">
suggesting that the operators should do everything that can be safely done to get as much shine off there butt before it gets really hot.
Can you spell it out a little bit more clearly!
Thanks.
Mutt.
I unfortunately have to understand the noise game, but I haven’t got a clue as to what you are talking about <img src="smile.gif" border="0">
suggesting that the operators should do everything that can be safely done to get as much shine off there butt before it gets really hot.
Can you spell it out a little bit more clearly!
Thanks.
Mutt.
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I guess that was also a bit crass. I just have put some real time into long technical discussions on here and then get flamed for it.
All airlines have to be noise conscious these days. Problem is, most really want to lower their levels, but few understand how to operationally do it. I won't preach to the choir and explain all the many things that can and do affect the perceived noise of large aircraft. Things are tightening up, everyday there are more politicians screaming about airport noise.
We have made great leaps in reduction since the 70s, but the reductions are getting smaller and smaller. The airports have to be able to show regular reductions in the amount of noise leveled on any one area to at least appear they are doing something.
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. Airports will have to pass on the cost of a wider area of noise suppression installations in homes to the airlines if they start losing court battles. All those 747s landing at LHR makes that place especially targeted.
Without looking I am not sure how many operations into LHR happen a day for 747s. I do know there is approximately a 2 dB difference in EPNL levels flaps 25 vs 30 on a 747. On the older ones it can be as much as 3 dB.
Using 2 dB, a crude calculation of an airline choosing to operate at Flaps 25 vs 30 would reduce it's operational noise dump by 2%. Doesn't sound like much, but it will add up fast as more and more operators follow suit, if they do. Hence the glass takes longer to fill.
The flaps 25 for 747s is just one small step. There is much more they could do that is not suggested by the manufacturer and should be mandated by the FAR/JAR regulations.
If airlines had to regularly qualify the acoustic configuration or condition of their airplanes they would become more conscious of the vast number of things that can reduce operational noise levels. Things they are already doing on a day to day basis. They just need to be shown how doing maintenance one way vs another can help or hurt the acoustic configuration of their aircraft. Even if it wasn’t forced I think they would be doing some of these things anyway. They just need to be taught how to look at how they acoustically maintain their aircraft. I know that an aircraft in poor acoustic shape can lose as much as 40% of it’s delivered ability to meet the FAR 36 Certified noise levels.
I can walk around an airplane and tell by looking if the plane has any chance of passing a test to see if it still meets what it was certified to noisewise. Let me look at the maintenance records and I can tell a lot more.
Aircraft are noise certified at constant thrust. The majority of aircraft today are landing with auto throttles on and is one reason why monitors show higher noise levels than cert. How conscious a pilot is to how he flies the airplane and how it affects monitored noise levels is another. Pilot input to controls and aircraft maintenance affects how much the auto throttle has to work(move around). If it is constantly jumping around chances are it is bumping the engines to maintain speed. The more it bumps the more noise the engine dumps. This can be helped.
I kinda rambled on past the intent of what I wanted here. Sorry if it was too boring.
Time for bed.
All airlines have to be noise conscious these days. Problem is, most really want to lower their levels, but few understand how to operationally do it. I won't preach to the choir and explain all the many things that can and do affect the perceived noise of large aircraft. Things are tightening up, everyday there are more politicians screaming about airport noise.
We have made great leaps in reduction since the 70s, but the reductions are getting smaller and smaller. The airports have to be able to show regular reductions in the amount of noise leveled on any one area to at least appear they are doing something.
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. Airports will have to pass on the cost of a wider area of noise suppression installations in homes to the airlines if they start losing court battles. All those 747s landing at LHR makes that place especially targeted.
Without looking I am not sure how many operations into LHR happen a day for 747s. I do know there is approximately a 2 dB difference in EPNL levels flaps 25 vs 30 on a 747. On the older ones it can be as much as 3 dB.
Using 2 dB, a crude calculation of an airline choosing to operate at Flaps 25 vs 30 would reduce it's operational noise dump by 2%. Doesn't sound like much, but it will add up fast as more and more operators follow suit, if they do. Hence the glass takes longer to fill.
The flaps 25 for 747s is just one small step. There is much more they could do that is not suggested by the manufacturer and should be mandated by the FAR/JAR regulations.
If airlines had to regularly qualify the acoustic configuration or condition of their airplanes they would become more conscious of the vast number of things that can reduce operational noise levels. Things they are already doing on a day to day basis. They just need to be shown how doing maintenance one way vs another can help or hurt the acoustic configuration of their aircraft. Even if it wasn’t forced I think they would be doing some of these things anyway. They just need to be taught how to look at how they acoustically maintain their aircraft. I know that an aircraft in poor acoustic shape can lose as much as 40% of it’s delivered ability to meet the FAR 36 Certified noise levels.
I can walk around an airplane and tell by looking if the plane has any chance of passing a test to see if it still meets what it was certified to noisewise. Let me look at the maintenance records and I can tell a lot more.
Aircraft are noise certified at constant thrust. The majority of aircraft today are landing with auto throttles on and is one reason why monitors show higher noise levels than cert. How conscious a pilot is to how he flies the airplane and how it affects monitored noise levels is another. Pilot input to controls and aircraft maintenance affects how much the auto throttle has to work(move around). If it is constantly jumping around chances are it is bumping the engines to maintain speed. The more it bumps the more noise the engine dumps. This can be helped.
I kinda rambled on past the intent of what I wanted here. Sorry if it was too boring.
Time for bed.
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I find your comments interesting rather than boring especially the part about
I can walk around an airplane and tell by looking if the plane has any chance of passing a test to see if it still meets what it was certified to noisewise. Let me look at the maintenance records and I can tell a lot more.
What exactly are you looking for during the walkaround?
Noise is becoming a right P.I.T.A. the days when we were able to say we are Stage 3 are long gone. We are now getting forced to do aerial gymnastics to avoid noise monitors with takeoff procedures based on the location of the monitor rather than normal procedures.
I wish that the airline industry was as powerful as the noise lobbyists, the industry has achieved wonders in the last 20 years, has any other part of the transport industry achieved so much ?.
Mutt. <img src="smile.gif" border="0">
I can walk around an airplane and tell by looking if the plane has any chance of passing a test to see if it still meets what it was certified to noisewise. Let me look at the maintenance records and I can tell a lot more.
What exactly are you looking for during the walkaround?
Noise is becoming a right P.I.T.A. the days when we were able to say we are Stage 3 are long gone. We are now getting forced to do aerial gymnastics to avoid noise monitors with takeoff procedures based on the location of the monitor rather than normal procedures.
I wish that the airline industry was as powerful as the noise lobbyists, the industry has achieved wonders in the last 20 years, has any other part of the transport industry achieved so much ?.
Mutt. <img src="smile.gif" border="0">
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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.
<img src="smile.gif" border="0">
[ 13 January 2002: Message edited by: Checkboard ]</p>
[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.
<img src="smile.gif" border="0">
[ 13 January 2002: Message edited by: Checkboard ]</p>
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Ford Airlane - I can appreciate your confusion because the noise game can be quite confusing.
411A- I agree with Mutt we are professionals I will back off. We are, thanks to the efforts and sacrefices of many, free to our opinion.
The noise vs safety issue has become a very heated arguement. Mutt talks about new take off procedures that push the limits of safety. I myself have asked why are we doing this? But, I must look on the history of aviation and what an excellent track record we have. I stil don't like sacrificing safety for reducing the amount of noise being dumped on a person that is safe on the ground and chode to move next to an airport. But, this is the career I have chosen.....
Mutt- I am trying to start helping airlines reduce their operational costs from noise by teaching them how to look for what I am talking about. Problem is these things are relatively simple and I don't want to give up my secrets. Hence, I want to get paid for the costr savings they get.
If you work for an airline that is looking for this type of help I am available in about 4-5 weeks.
411A- I agree with Mutt we are professionals I will back off. We are, thanks to the efforts and sacrefices of many, free to our opinion.
The noise vs safety issue has become a very heated arguement. Mutt talks about new take off procedures that push the limits of safety. I myself have asked why are we doing this? But, I must look on the history of aviation and what an excellent track record we have. I stil don't like sacrificing safety for reducing the amount of noise being dumped on a person that is safe on the ground and chode to move next to an airport. But, this is the career I have chosen.....
Mutt- I am trying to start helping airlines reduce their operational costs from noise by teaching them how to look for what I am talking about. Problem is these things are relatively simple and I don't want to give up my secrets. Hence, I want to get paid for the costr savings they get.
If you work for an airline that is looking for this type of help I am available in about 4-5 weeks.
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Ford Airlane - I forgot to continue my thoughts on your comments.... You offer insight that is very valuable to me and I will sure to make note and share it with my colleagues. This information is in the true spirit of this thread and this forum. If you can offer insight into either BA or Qantas avg landing weights at LHR I am most interested. I have heard that Qantas avg 250 kilos.
Thanks for you informative comments.
I will look for more from you.
Cheers!
Thanks for you informative comments.
I will look for more from you.
Cheers!