AirAsia over run.
I am a pilot...but not a jet pilot.
I have travelled on dozens of Air Asia flights and my experience is that they use very little, if any, reverse thrust....relying on the wheel brakes most of the time.
I have travelled on dozens of Air Asia flights and my experience is that they use very little, if any, reverse thrust....relying on the wheel brakes most of the time.
Join Date: Jul 2011
Location: FG central
Age: 53
Posts: 140
Likes: 0
Received 0 Likes
on
0 Posts
As someone who only flies light aircraft, I would be interested to know how long it would take a medium jet (say 737/A320) to complete a circuit and have another go at landing.
Assuming a non controlled aerodrome, or at least no other traffic about.
Surely it can't add more than 5-8 minutes?
I just question the whole commercial pressure/ OTP mentality.
Having worked under the wing for a while, I've seen how flight/ground crews can claw back such a delay over the next few sectors and bring it all back on time. ( I know when the crew I worked with had to service a late aircraft, we'd make an extra effort to get it done as quick as possible to get it turned around).
Assuming a non controlled aerodrome, or at least no other traffic about.
Surely it can't add more than 5-8 minutes?
I just question the whole commercial pressure/ OTP mentality.
Having worked under the wing for a while, I've seen how flight/ground crews can claw back such a delay over the next few sectors and bring it all back on time. ( I know when the crew I worked with had to service a late aircraft, we'd make an extra effort to get it done as quick as possible to get it turned around).
I have travelled on dozens of Air Asia flights and my experience is that they use very little, if any, reverse thrust....relying on the wheel brakes most of the time.
As someone who only flies light aircraft, I would be interested to know how long it would take a medium jet (say 737/A320) to complete a circuit and have another go at landing.
Regarding the above post about reverse and autobrakes - the "medium" setting brings the aircraft to a halt very quickly - around 3000ft of ground run even with a full load of pax. At Gatwick for example, a touchdown at the right place enables the plane to vacate at the first RET located about 4500ft from the threshold.
Hence my comments that, not withstanding aquaplaning etc, a 7500ft runway should be ample.
Hence my comments that, not withstanding aquaplaning etc, a 7500ft runway should be ample.
Join Date: Oct 2013
Location: Tree
Posts: 222
Likes: 0
Received 0 Likes
on
0 Posts
A to D
All good stuff of course about the auto brakes.
Would you rely on brakes alone, on a wet rubber plastered runway in say S/E when the first monsoon rain has hit, even after being inform "braking action good"? What about in the old "Eastern Block" where you have unreported ice?
Selecting the reverse idle only in these conditions, doesn't seem right to me.
Maybe It's because I am probably a dinosaur.
All good stuff of course about the auto brakes.
Would you rely on brakes alone, on a wet rubber plastered runway in say S/E when the first monsoon rain has hit, even after being inform "braking action good"? What about in the old "Eastern Block" where you have unreported ice?
Selecting the reverse idle only in these conditions, doesn't seem right to me.
Maybe It's because I am probably a dinosaur.
Pegase Driver
Join Date: May 1997
Location: Europe
Age: 74
Posts: 3,693
Likes: 0
Received 0 Likes
on
0 Posts
Brookfield Abused : first you are barking at the wrong tree , the video is not from an Air Asia aircraft.
Secondly your " Capt Hindsight" comments and trial are harsh. Have you yourself been in such situation to pass such judgement ?
Idid not myself but have talked to a crew in after a runway excursion ,: 3 of 4 things not correct , among them the wind passed by ATC ( read from where the ground sensors were but totally different above the runway ) then one more thing coming up during the flare and you have to make a quick decision : 99% of the time the decision is right, and everybody claps and praise your experience, but in 1% it is wrong and there you go.
The border between hero and villain is very , very thin in flying.
Throwing stones are easy, especially on an anomymous Internet forum.
Secondly your " Capt Hindsight" comments and trial are harsh. Have you yourself been in such situation to pass such judgement ?
Idid not myself but have talked to a crew in after a runway excursion ,: 3 of 4 things not correct , among them the wind passed by ATC ( read from where the ground sensors were but totally different above the runway ) then one more thing coming up during the flare and you have to make a quick decision : 99% of the time the decision is right, and everybody claps and praise your experience, but in 1% it is wrong and there you go.
The border between hero and villain is very , very thin in flying.
Throwing stones are easy, especially on an anomymous Internet forum.
Sop_monkey - although I am familiar with A320 performance as I spent some time on the (level D) simulators in the course of my work a few years ago, I am not a pilot so can't really comment as to use of reverse on wet runways except to say that when autobrakes give a preset decel rate then the use of reverse to assist in that decel as much as possible, taking the strain off the brakes, would seem logical.
Join Date: Oct 2013
Location: Tree
Posts: 222
Likes: 0
Received 0 Likes
on
0 Posts
D to A
Ok understood. Forget all the the performance data for a moment.
The point I'm trying make with the brakes only and the reverse idle thing, is we cant be sure what braking action we are going to get in certain unexpected conditions and at the max speed. I do have a good idea the stopping efficiency of full reverse (not just idle), that is engaged ASAP upon touch down. Deciding late in the landing run to use more than reverse idle, maybe too late.
Over the last few years a certain country that is effected by the monsoons, have now required aircraft fitted with thrust reverse, to have them all operating, in the monsoon season. This is in-spite of landing distance calculations, as we all know, don't include the use of reverse. What does that tell you? Common sense has prevailed, that's how I interpret that..
Ok understood. Forget all the the performance data for a moment.
The point I'm trying make with the brakes only and the reverse idle thing, is we cant be sure what braking action we are going to get in certain unexpected conditions and at the max speed. I do have a good idea the stopping efficiency of full reverse (not just idle), that is engaged ASAP upon touch down. Deciding late in the landing run to use more than reverse idle, maybe too late.
Over the last few years a certain country that is effected by the monsoons, have now required aircraft fitted with thrust reverse, to have them all operating, in the monsoon season. This is in-spite of landing distance calculations, as we all know, don't include the use of reverse. What does that tell you? Common sense has prevailed, that's how I interpret that..
Would you rely on brakes alone, on a wet rubber plastered runway in say S/E when the first monsoon rain has hit, even after being inform "braking action good"? What about in the old "Eastern Block" where you have unreported ice?
Going back to the performance data......
The industry has changed the way landing distances are calculated recently. Airbus (not sure about Boeing as it's over ten years ago I last flew them) have come up with the RCAM (Runway Condition Assessment Matrix) for various runway conditions and a table for each condition. It's an attempt to make the assessment as objective as possible, but there are provisos. For example, if the runway id wet, you can use idle reverse but only provided you use the tables for conditions two below braking action 'Good' which is a wet runway. Obviously, it's up to the commander, but personally, I used the Good table with full reverse. Would I use idle reverse on a wet rubber covered runway - definitely not! Good advice has been given that in these conditions the runway should be described as "Slippery when Wet" and this equates to braking action 'Poor'. One should actually be considering not landing on this at all.
Autobrake works slightly differently in the two main types. Airbus is less positive, has less settings and requires a bit more consideration in it's use. For example, you may feel retardation but may not get the DECCEL green light in the selection button. This tells you that you are not achieving 80% of the desired rate and that you may have to take over and brake manually.
There is also a large level of misunderstanding about how carbon brakes work. They like being used heavily, and heavy use doesn't necessarily wear them quicker. For maximum braking, you have to get them hot - between 200 and 250 degrees for the A320 (depending on the brake manufacturer) and they don't fade. You should still get good braking up to 900 degrees - and at this stage they are glowing bright red!
Carbon brakes wear every time the brakes are applied. As they cool after use, the top layer oxidises and this is what gets worn away on the next application. So if you use full reverse on landing, the brakes apply, then the reverse comes in. At this point, the brakes release a bit to maintain the set deceleration rate. When you stow the reversers, the brakes apply a bit more again to maintain the deceleration rate. By using reverse thrust, you achieve the same landing distance, but e=wear the brakes more and use more fuel. In dry conditions, there is little or no benefit in using full reverse thrust. In wet conditions, or worse, the brakes may not achieve the full selected deceleration rate, and this is where greater than idle reverse thrust should be considered to achieve the desired rate and reduce the landing distance.
It's an airmanship thing!
Join Date: Jun 2008
Location: 31000FR
Posts: 60
Likes: 0
Received 0 Likes
on
0 Posts
Airmanship?
Airmanship is a dead duck in many airlines, especially in the developing part of the world; it has been superseded by SOP, and it is standard practice to use FDR data to punish pilots who deviate for whatever reason.
SOP is good and necessary for many reasons, but when it is used to save the airline a bit of fuel it becomes questionable if the PIC is not given options.
Fuel uplift, routing, flap settings, Take off thrust, use of reverse, GA & diversions
are among the areas where the PIC in reality has no longer a say if he wants to stay out of trouble.
Combine that with cultures where it is easy to intimidate the pilots, and you will find some appalling CRM, where among other things it is unthinkable that the F/O will challenge the PIC during an unstable approach.
It has been a 10-year uphill battle as Airbus instructor mostly in Asia to make my students appreciate that there may be times when a GA, a TOGA takeoff, a full flap/full reverse landing etc. is in place despite SOP "recommending" a fuel saving option with smaller or no margins. There is a widespread reluctance among my pilots to accept the responsibility that comes with showing airmanship, maybe because e.g. a simple GA is an "event" that you have to defend afterwards.
Thanks Dan for the brake brief. May I add that full reverse actually reduces landing distance by about 10% if combined with MED auto brake on a slightly slippery runway (A330 figs)
Any of you 320 experts who can confirm from the pics that CONF 3 was used?
SOP is good and necessary for many reasons, but when it is used to save the airline a bit of fuel it becomes questionable if the PIC is not given options.
Fuel uplift, routing, flap settings, Take off thrust, use of reverse, GA & diversions
are among the areas where the PIC in reality has no longer a say if he wants to stay out of trouble.
Combine that with cultures where it is easy to intimidate the pilots, and you will find some appalling CRM, where among other things it is unthinkable that the F/O will challenge the PIC during an unstable approach.
It has been a 10-year uphill battle as Airbus instructor mostly in Asia to make my students appreciate that there may be times when a GA, a TOGA takeoff, a full flap/full reverse landing etc. is in place despite SOP "recommending" a fuel saving option with smaller or no margins. There is a widespread reluctance among my pilots to accept the responsibility that comes with showing airmanship, maybe because e.g. a simple GA is an "event" that you have to defend afterwards.
Thanks Dan for the brake brief. May I add that full reverse actually reduces landing distance by about 10% if combined with MED auto brake on a slightly slippery runway (A330 figs)
Any of you 320 experts who can confirm from the pics that CONF 3 was used?
Airmanship is a dead duck in many airlines, especially in the developing part of the world
Any of you 320 experts who can confirm from the pics that CONF 3 was used?
Join Date: Oct 2013
Location: Tree
Posts: 222
Likes: 0
Received 0 Likes
on
0 Posts
Capt T
I cocur. getting close to 100% responsibility and NO authority, if we aren't there already.
" and it is standard practice to use FDR data to punish pilots " you may add CVR to that.
I cocur. getting close to 100% responsibility and NO authority, if we aren't there already.
" and it is standard practice to use FDR data to punish pilots " you may add CVR to that.
I'm putting my money on a high and fast approach, quite likely not configured in time. Commencing a 3 degree approach from 3900' has plenty of potential to end up unstabilised if not flown correctly.
Even if flown in managed mode via the arc, the aircraft will tend to cut in towards the runway and may not overfly the calculated descent point requiring manual intervention with an increased ROD to regain the profile.
Even if flown in managed mode via the arc, the aircraft will tend to cut in towards the runway and may not overfly the calculated descent point requiring manual intervention with an increased ROD to regain the profile.
