747 Classic landing flaps
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747 Classic landing flaps
I would like to hear from folks who currently fly the classic or have done so in the past. What does your company use? 25 or 30? Have you had any flap track problems from using 30 degrees?
What about auto brakes? use them all the time? whether you need them or not?
Personally, i like flaps 30, and no auto brakes on long runways. I love auto brakes on short runways. Just trying to get a feel for what other operators use.
Thanks in advance
What about auto brakes? use them all the time? whether you need them or not?
Personally, i like flaps 30, and no auto brakes on long runways. I love auto brakes on short runways. Just trying to get a feel for what other operators use.
Thanks in advance
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Atlas/Polar policy, Flaps 25 unless 30 is required for a short runway. Auto brakes always used, unless you have a long runway and high OAT.
Atlas has been back and forth on the 25/30 policy. Just depends on who's making the decisions. I've noticed very little differance in the picture due to pitch variations and only 5 kts slower.
Atlas has been back and forth on the 25/30 policy. Just depends on who's making the decisions. I've noticed very little differance in the picture due to pitch variations and only 5 kts slower.
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the flap track problems have been around for a long time. History of 'canoe fairings' also falling off. I belive that it actual problem was to do with stress fractures or similar, hence the flap 25 SOP of many operators. I cant suggest a technical reference though Im afraid.
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25 vs 30 flap: From the operators side its five knots and a little longer landing roll. As a general rule 25 flaps will add about 2% to the landing distance as compared to a 30 flap landing.
The angle of attack is the same for both landings.
The best answer is which costs less. 25 flaps win. The get the check on maintenance, and fuel savings. 30 flaps only leads in landing distance and maybe gets the nod on brake savings.
Maybe the touch down point and how much energy is used at touch down is important.
Brakes: It is the old brakes, not the new carbon brakes. These old brakes heat up quick and are rather slow to cool. Most companies select auto brakes, min for normal landings, and med for wet runways, cause the brakes last longer and usually stay just a bit cooler. Thus cheaper to operate and maintain. Auto brakes look for a steady deceleraton rate and have a delay built into the application of several seconds in the min and med position.
Most companies also do not train on the best method for keeping the brakes cooler when using manual brakes. A good number of drivers love to make sure the brakes are going to work, so the make a jab at the peddles just after touchdown. This generates heat. Second a lot of drives think just holding minimum pressure on the brakes will keep them cool. Want to keep them cool with manual braking? Stay off the peddles till below 100 kts. Then come on nice and firm felling the decelleration in the straps. One application right down to taxi speed. When on the taxi way, stay off the brakes until you need to slow down and bring it right down to a slow taxi. Shut down exessive engines.
Auto brakes work great on most runways. The only real exception is hot day and long runway.... This of course is based on weight but at the weights near max landing a long runway would be anything above 3000m. At light weights say 220.0 kgs or less this could be 2500m.
This last point may touch a few egos. At weights when the runway becomes minimum, make sure to touch down at the planned point and let it touch with a nice solid bang. The solid bang eats at the energy thus needing less braking action and the touch down point gives you the runway length you need to stop. Grease jobs are not wanted when runway length is in question.
I always like flaps 30 and no brakes, I only get my way maybe 1 in 10.
Nuff said
The angle of attack is the same for both landings.
The best answer is which costs less. 25 flaps win. The get the check on maintenance, and fuel savings. 30 flaps only leads in landing distance and maybe gets the nod on brake savings.
Maybe the touch down point and how much energy is used at touch down is important.
Brakes: It is the old brakes, not the new carbon brakes. These old brakes heat up quick and are rather slow to cool. Most companies select auto brakes, min for normal landings, and med for wet runways, cause the brakes last longer and usually stay just a bit cooler. Thus cheaper to operate and maintain. Auto brakes look for a steady deceleraton rate and have a delay built into the application of several seconds in the min and med position.
Most companies also do not train on the best method for keeping the brakes cooler when using manual brakes. A good number of drivers love to make sure the brakes are going to work, so the make a jab at the peddles just after touchdown. This generates heat. Second a lot of drives think just holding minimum pressure on the brakes will keep them cool. Want to keep them cool with manual braking? Stay off the peddles till below 100 kts. Then come on nice and firm felling the decelleration in the straps. One application right down to taxi speed. When on the taxi way, stay off the brakes until you need to slow down and bring it right down to a slow taxi. Shut down exessive engines.
Auto brakes work great on most runways. The only real exception is hot day and long runway.... This of course is based on weight but at the weights near max landing a long runway would be anything above 3000m. At light weights say 220.0 kgs or less this could be 2500m.
This last point may touch a few egos. At weights when the runway becomes minimum, make sure to touch down at the planned point and let it touch with a nice solid bang. The solid bang eats at the energy thus needing less braking action and the touch down point gives you the runway length you need to stop. Grease jobs are not wanted when runway length is in question.
I always like flaps 30 and no brakes, I only get my way maybe 1 in 10.
Nuff said
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MustangSally.
Good post MustangSally--Especially the point about landing firm and having less energy to dissipate vs. landing smooth. Something I had suspected but never heard anyone else talk about.
But I might disagree on one point. You wrote, with respect to F25 vs. F30 landings: <<The angle of attack is the same for both landings.>>
I won't argue the AoA statement because I just don't know. But the *sight* picture, in other words, the pitch attitude is flatter with F30 vs. F25 and that's why my company requires F30 for CATII operations.
But I might disagree on one point. You wrote, with respect to F25 vs. F30 landings: <<The angle of attack is the same for both landings.>>
I won't argue the AoA statement because I just don't know. But the *sight* picture, in other words, the pitch attitude is flatter with F30 vs. F25 and that's why my company requires F30 for CATII operations.
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The book (mine anyway!) for the 400 shows one degree difference in pitch attitude between 25/30. FL25-2.5*/3*GS. FL30-1.5*/3*GS. Ref obviously will vary with weight and FF is slightly higher with 30*.
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Flaps 25 means lower noise on approach and lower fuel flows.
Flaps 30 means shorter landing run required and better pitch angle for autoland.
However, if you wish to land at high ambient temps with high landing weight and short turnround time, then use flaps 30 and full reverse with manual brakes applied below 100 kts (runway length permitting).
If at medium weights and turnround time and runway length not a factor, then use flaps 25 and reverse idle,autobrakes 2 or 3.
Engine wear is more expensive than brake wear.
In all cases, hitting the touchdown point, on the centreline,(preferably firmly when wet) is the best method!!
Flaps 30 means shorter landing run required and better pitch angle for autoland.
However, if you wish to land at high ambient temps with high landing weight and short turnround time, then use flaps 30 and full reverse with manual brakes applied below 100 kts (runway length permitting).
If at medium weights and turnround time and runway length not a factor, then use flaps 25 and reverse idle,autobrakes 2 or 3.
Engine wear is more expensive than brake wear.
In all cases, hitting the touchdown point, on the centreline,(preferably firmly when wet) is the best method!!
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Damn good info!
My company uses flaps 30, no one uses Autobrakes. Most of the runways we land on are long. But our biggest problem is the huge ego's we have in our left seat. They think they can brake more efficiently than autobrakes. Nice post MustangSally! I'm cuttin and pasting your post for future reference. Doesn't this topic belong in the tech forum?
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Sometimes when landing at night, if it's been snowing all day at the airport of intended landing, you cannot see the airport surface while on final approach. This makes a good case for landing with autobrakes to account for the unknown condition of the runway. Braking will start immediately and will cover you if the runway is nice and dry at the touchdown point and midpoint, but is still icy and snowy at the far end. Some of our pilots on the classic had some interesting landings at a far north airport in years past when our braking policy was to use no autobrakes, reverse only until around 80 or 90 knots, and then use manual brakes. Of course, the control tower gave braking action reports, but the accuracy of those reports are marginal at best and you don't really know what you have until you touch down and start braking. The airport's policy was to remove snow and ice at the approach and midpoint portions of the runway, but not the departure end. Therefore, braking action reports for this particular airport were valid for the first 2/3 of the runway. You can see how you are set up for failure in this case. You roll through the good braking area of the runway, and start manual brakes just when you enter the departure portion of the runway, and braking is very marginal, risking running off the end. With manual brakes you risk wasting good runway surface where positive braking can occur. Those incidents inspired us to mandate the use of autobrakes on all landings, and we've had no similar problems ever since - some 13 years ago.
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Another issue with the auto brakes is even use. Before Atlas required AutoBrakes, we would end up with one side in the red and the other side mid green. Everyone has one foot that is heavier then the other. Since using autobrakes, fairly even temps.
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Our SOP is 30 and autobrakes.
25 above certain LW to stay in Chapter 3 noise limits.
Autobrakes MED are the norm, light weights & dry runway we can use MIN.
If you want to keep brake temp to minimum, land with autobrakes OFF, and start braking at lower speeds, because the most energy is at the higher speeds.
Use maximum reverse thrust down to 80kts, slower if needed.
25 above certain LW to stay in Chapter 3 noise limits.
Autobrakes MED are the norm, light weights & dry runway we can use MIN.
If you want to keep brake temp to minimum, land with autobrakes OFF, and start braking at lower speeds, because the most energy is at the higher speeds.
Use maximum reverse thrust down to 80kts, slower if needed.
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Historically, the 100's shed more bits of flaps as age took it's toll. I believe the recommendation to use Flaps 25 for landing came about because of this problem, also the selection of flaps just above the min. bug speed rather than just below placarded maximum speed. The 200's/300's had a more robust flaps engineering as does the 400 series.
BA used 25 because of the bits dropping off problem. As I mentioned earlier, there was a mod to the flap tracks to prevent this. All the Classics I flew had the mod and we used 30. however, these were freighters which often land a lot heavier than pax aircraft. Keeping the steel brakes cool was the main prority. one time we used to use 25 was when the aircraft was landing empty. The attitude at 30 was just a bit flat at 30 and 25 negated the risk of banging the nose wheel on first.
In my previous company, I was flying pax 400s. Always 30.
In my previous company, I was flying pax 400s. Always 30.
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Flaps and Brakes
Remember flying often with one particular Captain. He would not use auto-brakes unless weather/ RWY lenght, conditions or combination thereof dictated their use.
His technique was very simple. Use full RWY lenght available. Touch down in the TD zone on speed, use reverse at high speed adhering to the schedule reaching idle by 60kts and only when in the low speed regime would he apply brakes.
While taxying, keep the feet off the pedals, let the speed built up and then brake to a slow speed. No more than 20 kts to avoid tire sidewall heating during long taxy.
Even when flying in Saudi Arabia and relatively short sectors I never saw brake temps go above the top of the "Green" to very low "Amber". Heard the same from most of the ground engineers and others that flew with the guy.
Flaps 30 landing are standard landing flaps with Air Atlanta. There are some that use flaps 25. What is better, well both have their advantages.
His technique was very simple. Use full RWY lenght available. Touch down in the TD zone on speed, use reverse at high speed adhering to the schedule reaching idle by 60kts and only when in the low speed regime would he apply brakes.
While taxying, keep the feet off the pedals, let the speed built up and then brake to a slow speed. No more than 20 kts to avoid tire sidewall heating during long taxy.
Even when flying in Saudi Arabia and relatively short sectors I never saw brake temps go above the top of the "Green" to very low "Amber". Heard the same from most of the ground engineers and others that flew with the guy.
Flaps 30 landing are standard landing flaps with Air Atlanta. There are some that use flaps 25. What is better, well both have their advantages.
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Ayone know what NCA uses?
how about Cargo 360?
Dragon Air?
Focus?
Seems to be 50/50 split
I like what Atlanta driver said, thats pretty much the way I used to operate until i was chastised by management.
how about Cargo 360?
Dragon Air?
Focus?
Seems to be 50/50 split
I like what Atlanta driver said, thats pretty much the way I used to operate until i was chastised by management.