The over use of autobrakes
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I can, the brakes will engage automatically, or I can disengage by braking. If I don't want to use the brakes the only way to achieve that is to not use auto brakes. I'm in and out of Vegas all the time and have had to lower the gear after take off several times because of temperature. I don't use the brakes until I reach 80kts during roll out, anytime you use auto brakes you will be waiting at the hold short line for the brakes to cool on the next sector.
Even when landing in Vegas, I set LOW, then turn them off soon after touchdown if desired. I've got 4 seconds to do that if I don't want the AB at all. If I'm concerned about brake temps, a bit more reverse helps.
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Heavy with tail wind/crosswind, I will use autobrake as it will definitely do a better job than me. With a light A319 especially with headwind I won’t arm autobrake and actually most of time not use the brake at all, only a bif of reverse thrust then a small brake application to vacate the runway. Then you arrive at the gate, you don’t even need brake fan. I love it!
Pprune is a window on people and human performance.
Posters have expressed their views on aircraft systems; many contributions appear to reflect the overrun accident statistics.
What we say or what we write in forums represents what we think, and often those thoughts which affect behaviour in everyday operation. (And beware of covert influence of other’s views on our thoughts).
There have been many discussion about automation. Autobrake is automation, this appears to be more acceptable than that for flight control, but there are similar problems such as lack of feed-back; lack of feel between applied brake effort (feet on pedals) and deceleration. So why no calls for more manual braking practice?
Also, using autobrake with thrust reverser we lose the ability to differentiate between brake based retardation and that of reverse, where the former relates to surface conditions, and the latter effectiveness reduces with reducing speed.
Thus whilst automation offers advantages, it must be appreciated that some operating features required ‘piloting’ compensation.
The skills required are those of judgement - choice of safest option - which requires good knowledge of aircraft systems and the environment, but unless we seek knowledge and practice, these skills might not improve.
Part of this judgement is to realise that future action is uncertain - “no one size fits all”, thus the task is to manage uncertainty.
What might be deduced from this thread, even when allowing for the non-professional input, is that the level of uncertainty in aviation appears to be increasing.
Posters have expressed their views on aircraft systems; many contributions appear to reflect the overrun accident statistics.
What we say or what we write in forums represents what we think, and often those thoughts which affect behaviour in everyday operation. (And beware of covert influence of other’s views on our thoughts).
There have been many discussion about automation. Autobrake is automation, this appears to be more acceptable than that for flight control, but there are similar problems such as lack of feed-back; lack of feel between applied brake effort (feet on pedals) and deceleration. So why no calls for more manual braking practice?
Also, using autobrake with thrust reverser we lose the ability to differentiate between brake based retardation and that of reverse, where the former relates to surface conditions, and the latter effectiveness reduces with reducing speed.
Thus whilst automation offers advantages, it must be appreciated that some operating features required ‘piloting’ compensation.
The skills required are those of judgement - choice of safest option - which requires good knowledge of aircraft systems and the environment, but unless we seek knowledge and practice, these skills might not improve.
Part of this judgement is to realise that future action is uncertain - “no one size fits all”, thus the task is to manage uncertainty.
What might be deduced from this thread, even when allowing for the non-professional input, is that the level of uncertainty in aviation appears to be increasing.
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I don't know about other airplanes, but there is plenty of feedback in the brake pedals on the 744, such that I can discern when they are releasing for a slippery runway. That holds true when using Autobrakes as well, as long as I rest my feet on the pedals.
Manual braking practice is definitely a good idea! Get a good idea of speed vs runway distance marker on a familiar runway when using your normal autobrake setting. Attempt to replicate that using manual braking. Just don't use heavy braking at first - let reverse thrust do its work, and slowly add braking force.
Manual braking practice is definitely a good idea! Get a good idea of speed vs runway distance marker on a familiar runway when using your normal autobrake setting. Attempt to replicate that using manual braking. Just don't use heavy braking at first - let reverse thrust do its work, and slowly add braking force.
One major Australian airline operating a Boeing 747 over-ran a 10,000 ft runway following a botched touch down in heavy rain. Due to a combination of crew errors the autobrake was inadvertently disarmed without the crew being aware. From that experience, the operator mandated that autobrakes were to be armed for every landing on its 737 fleet, regardless that the incident aircraft was a Boeing 747.
Thread Starter
From the ATSB report.
The captain cancelled the go-around decision by retarding the thrust levers. It is very
widely accepted that a decision to conduct a go-around should not be reversed. In this case, the cancellation action had a number of side-effects. It resulted in excess thrust after touchdown, a slight delay in spoiler deployment, cancellation of the auto-brakes (due to the number 1 thrust level being advanced for more than 3 seconds),
widely accepted that a decision to conduct a go-around should not be reversed. In this case, the cancellation action had a number of side-effects. It resulted in excess thrust after touchdown, a slight delay in spoiler deployment, cancellation of the auto-brakes (due to the number 1 thrust level being advanced for more than 3 seconds),
Join Date: Jul 2000
Location: Nirvana..HAHA..just kidding but,if you can tell me where it is!
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Use those fans at high speed(reverse). then feed in the brakes at lower speed..gives the coolest brake temps..as has been said,many times here...works a treat.
On the A320, auto brake commands a deceleration rate rather than a fixed setting, therefore when used in combination with MAX reverse the brake application isn’t too hard as the engines do most of the work.
I’m surprised that the A380 “brake to vacate” technology hasn’t become more widespread given the obvious benefits.
From experience in a Asian city where young first officers are likely not to own a car, judgment of distance vs deceleration rate to make a particular exit is lacking. Most car drivers develop this skill when a traffic light ahead turns red.
I’m surprised that the A380 “brake to vacate” technology hasn’t become more widespread given the obvious benefits.
From experience in a Asian city where young first officers are likely not to own a car, judgment of distance vs deceleration rate to make a particular exit is lacking. Most car drivers develop this skill when a traffic light ahead turns red.
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And provoke a go-around while passing the 22L localizer exiting at Z at JFK (last exit of the runway, 8000 feet)
Emirates and Etihad are the prime candidates.
In contrast a heavy 747 on approach even announced it would need the full runway implicating increased spacing requirements as conditions where below CATI. And they managed to take the exit before the last one in contrast to some A380s which seem to take that exit on purpose.
Oh well i guess it's a little bit of ATC failure to recognize the problem and tell the crew also.
Not so relevant right now because the A380s are not coming in by the minute.
But still also landing other runways BTV seems to encourage taking quite some time on the runway delaying the exit.
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Oh well I guess it's a little bit of ATC failure to recognize the problem and tell the crew also.
However, and this is a generalisation, not at USATC, I find it irritating, unnecessary etc. etc. if ATC issues an expedite vacating after you've touchdown. That is too late. If you want to vacate longer than is expected , by you & ATC, then you ask; but if ATC wants to shorten your landing roll they should ask well out on finals.
However, and this is a generalisation, not at USATC, I find it irritating, unnecessary etc. etc. if ATC issues an expedite vacating after you've touchdown. That is too late. If you want to vacate longer than is expected , by you & ATC, then you ask; but if ATC wants to shorten your landing roll they should ask well out on finals.
Good point, at Changi we get an ATC report on our runway occupancy times each month including a league table of the operators and any outstandingly slow performances highlighted.
Expactiations of how long it should take and which exit we are expected to use are given.
Hong Kong is notorious for “encouraging” landing aircraft to vacate as soon as possible, even in the wet which has resulted in a runway excursion or two.
Expactiations of how long it should take and which exit we are expected to use are given.
Hong Kong is notorious for “encouraging” landing aircraft to vacate as soon as possible, even in the wet which has resulted in a runway excursion or two.
Said airline that put a 747 into the golf course now has an idle reverse policy!!! It beggars belief.
Many who have been there a long time believe the stars are aligning for another overrun.
The financial benefits of five years’ idle reverse and single engine taxi policy will be wiped out in a heartbeat when one trundles off the end.
Many who have been there a long time believe the stars are aligning for another overrun.
The financial benefits of five years’ idle reverse and single engine taxi policy will be wiped out in a heartbeat when one trundles off the end.
Thread Starter
Said airline that put a 747 into the golf course now has an idle reverse policy!!! It beggars belief.
In those days, the only runway on Nauru was 5200 feet long with the ocean at each end. No runway end safety areas. The TVASIS was often u/s due lack of maintenance. The Indian Airlines crews (all "captains") duly arrived and brought with them their own company procedures, which included idle reverse for all landings. This was not to save fuel or other costs but for stated noise abatement reasons. There was no noise abatement policy on Nauru. Many houses were only 100 yards along the full length of the runway and it wasn't practical for several reasons. One being obese young islanders in the habit of cruising around the island in rusty Landrovers with a bevy of amplifiers belting out ABBA and other pop music at Strength 10. Or noisier still, riding their huge Yamaha motor bikes along the airport road at full blast.
Prior to the Indian Airlines crews arriving to fly the Air Nauru 737's, it was not only SOP but common sense airmanship, to use full reverse on every landing. This was vital if the runway was wet because it wasn't grooved and braking efficiency was less. Nevertheless, airmanship was not part of the Indian Airlines lexicon (indeed the airline in those days had the worst accident record in the world) and these pilots refused to use anything more than idle reverse regardless of surface conditions and the waiting sharks in the Pacific Ocean at the end of the runway.
Brake and tyre wear rocketed as well as the shattered nerves of the few Australian first officers left to crew with the Indian captains. The combination of hard landings and hard braking also scared those Nauruan passengers who occasionally flew on the airline. One particular very hard landing and subsequent heavy braking (and idle reverse
) caused one lady passenger to be thrown about and she suffered a broken tooth.The problem was that she happened to be the President's daughter. With that, a posse of Nauruan women had an audience with the then President (Hammer De Roburt) and demanded he send all the Indian pilots back home.
Eventually, Australian crews from the 1989 era arrived on Nauru and the comforting full throated roar of full reverse signalling the arrival of a 737 carrying news from the outside world, was heard once again.
Last edited by Centaurus; 3rd Mar 2018 at 02:11.
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Cent.
I really dont understand this quite common "idle reverse" policy.Sure a major survey SUGGESTED that it saves money versus using wheel brakes, but this is now excluding piloting or airmanship or what many now call CRM skills, based on a crews assessment of the landing conditions they are facing on the day.Policy should only be a GUIDE not a LAW.Autobrakes are part of the automation we now accept as part and parcel of our lives as pilots, but any APPROPRIATE method is acceptable based upon your individual
experience on the day surely?
I really dont understand this quite common "idle reverse" policy.Sure a major survey SUGGESTED that it saves money versus using wheel brakes, but this is now excluding piloting or airmanship or what many now call CRM skills, based on a crews assessment of the landing conditions they are facing on the day.Policy should only be a GUIDE not a LAW.Autobrakes are part of the automation we now accept as part and parcel of our lives as pilots, but any APPROPRIATE method is acceptable based upon your individual
experience on the day surely?
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In the Sim I sometimes distract the crew and sneakily switch the autobrakes off, just to see if they notice the end of the runway coming up. Sure, it would normally give you an "Autobrake" EICAS and you'd hear the click, but....
Idle reverse and 'low' / 2or3 autobrake is a valid technique. On susceptible aeroplanes this may not give the best brake temperature management if that is an operational concern.
'Brake to Exit' is a great function if fitted.
The flipside is that crews need to be aware of 'normal' deceleration rates and the limitations of autobraking systems when confronted with less optimal conditions. Such as: Touchdown point/Approach speed/Surface conditions/Actual wind/ Turn off/ Traffic etc.
Therefore, Airmanship would hopefully result in early application of 'Normal' [not idle!] reverse thrust selection and manual braking should it be deemed necessary.
'Brake to Exit' is a great function if fitted.
The flipside is that crews need to be aware of 'normal' deceleration rates and the limitations of autobraking systems when confronted with less optimal conditions. Such as: Touchdown point/Approach speed/Surface conditions/Actual wind/ Turn off/ Traffic etc.
Therefore, Airmanship would hopefully result in early application of 'Normal' [not idle!] reverse thrust selection and manual braking should it be deemed necessary.
Cunning Artificer
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I have seldom read such a load of rubbish. If this reflects current teaching about the design, function and use of automatic braking then everyone needs to go back to school and study how it works in reality.