F100 - Overshot Runway at Newman Airport (9/1/2020)
For the in-flight case, the regulations allow the use of a 15% buffer if actual landing distance data is available. Both Airbus and Boeing provide advisory data that includes information for a variety of brake settings. The pilot can input the actual brake setting, environmental conditions and aircraft configuration, and calculate an accurate landing distance, to which the 15% buffer is applied. The pilot then knows exactly how much margin is available, assuming the landing occurs within the normal touchdown zone.
The following might be of interest:
https://ifalpa.org/media/2030/12adob...g-aircraft.pdf
Flysmart in the dispatch mode, does not take into account reverse or brake mode.
Flysmart in the inflight mode, let’s you choose these.
So when I have data that has a very specific set of circumstances in it to spit out a calculation, based upon the exact situation on the ground and using the exact braking options, why can’t I use 15%? 67% would be a huge overkill.
If I as a captain refused to land on a runway that was plenty long enough for the conditions at the time allowing for a 15% buffer, all because I said I wanted a 67% buffer, then they’d probably take me offline and ask me into the sim so I can prove that I can actually land the aircraft safely.
So if you're obliged to apply 1.67 - or in the worst case scenario, 1.92 - as the destination landing distance factor when calculating the take off weight calculation at 'dispatch', how does it make any difference when you get into the air and you find out that, for example, the destination conditions are as forecast? Do you magically increase weight mid flight?
Capn Bloggs & Lead Balloon
CAO 20-7-1B is very clear. Prior to dispatch, for a dry Runway 1.67 x LDR Dry or for a wet Runway 1.92 x LDR dry/Flight Manual or Ops Manual data for a wet runway shall be used. Once inflight 1.67 x LDR Dry or if actual landing distance data is supplied under its type certificate, 1.15 x Actual LD. Regarding Airbus and Boeing, actual LD is supplied under their Type Certificate. I can’t speak for Boeing but Airbus SOP is to use FlySmart calculations for Medium-Poor braking (contaminated) if the destination is forecasting weather conditions that would result in contaminated runway condition, otherwise 1.67 or 1.92. Also once in flight and the weather report indicates a wet runway, calculation should be based on Medium-Poor braking (Contaminated) if using reverse idle. It might surprise you but FlySmart landing calculations with 15% factoring and Medium-Poor braking is worse than 1.67 and 1.92 factoring on a dry runway.
The figures below are based on sea level, ISA conditions, zero wind at Max LW. 1.67 & 1.92 are based on max manual braking on a dry runway and the FlySmart figures are based on sea level, ISA conditions, zero wind at Max LW and Medium-Poor braking x 1.15.
A320-200: 1.67 = 6148, 1.92 = 7068, FlySmart = 7870
A321-200: 1.67 = 6318, 1.92 = 7293, FlySmart = 8024
A330-300: 1.67 = 7165, 1.92 = 8237, FlySmart = 8911
A350-900: 1.67 = 7831, 1.92 = 9003, FlySmart = 9427
A350-1000: 1.67 = 8023, 1.92 = 9224, FlySmart = 10727
CAO 20-7-1B is very clear. Prior to dispatch, for a dry Runway 1.67 x LDR Dry or for a wet Runway 1.92 x LDR dry/Flight Manual or Ops Manual data for a wet runway shall be used. Once inflight 1.67 x LDR Dry or if actual landing distance data is supplied under its type certificate, 1.15 x Actual LD. Regarding Airbus and Boeing, actual LD is supplied under their Type Certificate. I can’t speak for Boeing but Airbus SOP is to use FlySmart calculations for Medium-Poor braking (contaminated) if the destination is forecasting weather conditions that would result in contaminated runway condition, otherwise 1.67 or 1.92. Also once in flight and the weather report indicates a wet runway, calculation should be based on Medium-Poor braking (Contaminated) if using reverse idle. It might surprise you but FlySmart landing calculations with 15% factoring and Medium-Poor braking is worse than 1.67 and 1.92 factoring on a dry runway.
The figures below are based on sea level, ISA conditions, zero wind at Max LW. 1.67 & 1.92 are based on max manual braking on a dry runway and the FlySmart figures are based on sea level, ISA conditions, zero wind at Max LW and Medium-Poor braking x 1.15.
A320-200: 1.67 = 6148, 1.92 = 7068, FlySmart = 7870
A321-200: 1.67 = 6318, 1.92 = 7293, FlySmart = 8024
A330-300: 1.67 = 7165, 1.92 = 8237, FlySmart = 8911
A350-900: 1.67 = 7831, 1.92 = 9003, FlySmart = 9427
A350-1000: 1.67 = 8023, 1.92 = 9224, FlySmart = 10727
Last edited by 404 Titan; 7th Sep 2021 at 06:35.
Thanks 404T.
So you're sitting in your A3XY-Z at Brisbane, planning a flight to Hamilton Island (about 5,800' available) where the forecast and every other piece of information says it's raining heavily with a variable 5kt wind. You work out your takeoff weight based on the landing distance required in this circumstances.
What changes after you take off? Serious question, because I'm not 'getting it'.
I agree with you: The rule is pretty clear for the maximum 'dispatch' weight calculation. What I don't understand is how you 'change' anything after you take off. If it turns out the actual weather at your destination is 'better' than forecast, you can't add weight (unless, I suppose, you can somehow burn less fuel getting there than planned). If the weather is 'worse' than forecast, what then?
So you're sitting in your A3XY-Z at Brisbane, planning a flight to Hamilton Island (about 5,800' available) where the forecast and every other piece of information says it's raining heavily with a variable 5kt wind. You work out your takeoff weight based on the landing distance required in this circumstances.
What changes after you take off? Serious question, because I'm not 'getting it'.
I agree with you: The rule is pretty clear for the maximum 'dispatch' weight calculation. What I don't understand is how you 'change' anything after you take off. If it turns out the actual weather at your destination is 'better' than forecast, you can't add weight (unless, I suppose, you can somehow burn less fuel getting there than planned). If the weather is 'worse' than forecast, what then?
LB its like looking at a weather forecast. Pre-flight if the forecast indicates that you have to carry fuel to hold for 60 minutes or carry an alternate then the regs say carry it. Once you get airborne the weather changes so now you dont have to carry the fuel but it is on board anyway. Another example is ETOPS. Before take-off there are a whole bunch of rules that govern how much fuel you take and what level of equipment must be serviceable. When you are airborne basically you do what you have to do to complete the flight safely. So with the pre-flight LDR calcs you will work out if you can take the payload based on the forecast weather. Those calcs have different assumptions built into them. Once you get airborne (there is that phrase again) you work out if you can actually land at your destination based on the actual conditions and actual landing weight with different assumptions built into the calcs. So if you worked out pre-flight that you were limited then you might have reduced your fuel (tankering possibly) or payload. Inflight you are no longer interested in what might have been you are only interested in what is actually possible with your actual weight.
Hope this clears up your confusion.
Hope this clears up your confusion.
Lead Balloon
If the “Heavy Rain” means that the runway is contaminated, ie >3mm of standing water on >25% of the runway, FlySmart would be used prior to dispatch with forecast conditions and Medium-Poor braking, medium auto brake idle reverse x 1.15.
If “Heavy Rain” means the runway is wet, 1.92 x LDR dry would be used.
In both cases a landing performance would be calculated inflight using FlySmart with actual conditions, the actual landing weight, medium-poor braking if using idle reverse, medium auto brake x 1.15. If too short, recalculate with full reverse. If still too short recalculate with manual braking. Finally if still to short divert to your alternate. Where I fly we always carry an alternate but in the Australian context, an alternate probably should have been planned for based on the info you’ve provided.
I had a flight a few years ago into Perth with an A350-900. Forecast for Perth was a Tempo TS and rain with wind straight down RWY21 at 30kts. We don’t use 06/24 unless operationally required due to the shorter LDA. Also we normally plan Perth as an Island Reserve (2 hours holding Fuel) due to limited available alternates but on this night Dispatch planned Adelaide as an alternate due to WX. During the flight WX forecasts for Perth started to deteriorate with heavy rain, TS and winds straight across RWY 03/21 at up to 50kts. ATC had closed this RWY but in addition it was above the max Xwind for the A350. Rwy 24 was the only choice but with Medium-Poor braking and idle reverse, the Rwy was too short. I recalculated with full reverse and the numbers worked, just. I recalculated again with manual braking which gave me more fat. Based on the numbers we were going to have to exit Rwy 24 at the end via V but in the end was able to exit via A.
The point I’m making is that if on the day, the numbers don’t work make sure you have a plan B, preferably an alternate.
If the “Heavy Rain” means that the runway is contaminated, ie >3mm of standing water on >25% of the runway, FlySmart would be used prior to dispatch with forecast conditions and Medium-Poor braking, medium auto brake idle reverse x 1.15.
If “Heavy Rain” means the runway is wet, 1.92 x LDR dry would be used.
In both cases a landing performance would be calculated inflight using FlySmart with actual conditions, the actual landing weight, medium-poor braking if using idle reverse, medium auto brake x 1.15. If too short, recalculate with full reverse. If still too short recalculate with manual braking. Finally if still to short divert to your alternate. Where I fly we always carry an alternate but in the Australian context, an alternate probably should have been planned for based on the info you’ve provided.
I had a flight a few years ago into Perth with an A350-900. Forecast for Perth was a Tempo TS and rain with wind straight down RWY21 at 30kts. We don’t use 06/24 unless operationally required due to the shorter LDA. Also we normally plan Perth as an Island Reserve (2 hours holding Fuel) due to limited available alternates but on this night Dispatch planned Adelaide as an alternate due to WX. During the flight WX forecasts for Perth started to deteriorate with heavy rain, TS and winds straight across RWY 03/21 at up to 50kts. ATC had closed this RWY but in addition it was above the max Xwind for the A350. Rwy 24 was the only choice but with Medium-Poor braking and idle reverse, the Rwy was too short. I recalculated with full reverse and the numbers worked, just. I recalculated again with manual braking which gave me more fat. Based on the numbers we were going to have to exit Rwy 24 at the end via V but in the end was able to exit via A.
The point I’m making is that if on the day, the numbers don’t work make sure you have a plan B, preferably an alternate.
Thanks Lookleft.
I'm not confused about the difference between planning a flight and doing a flight. I have some exposure to and experience of the difference between forecast weather conditions and 'on paper' representations as to the conditions of a destination aerodrome, on the one hand, and dealing with reality on the other.
I'm confused about what and how you change things after you've taken off, having taken off at a weight calculated by reference to the conditions forecast before take off.
If you in fact "worked out pre-flight that you were limited [and you] reduced your fuel (tankering possibly) or payload", how do you increase fuel on board or passengers on board or cargo on board after take off, when you find out that the weather conditions at your destination are, in fact, 'better' than the ones you planned on? I can envisage you going a more direct route and landing with more fuel than planned, and therefore at a higher landing weight than planned. Any other way of landing heavier than planned, in accordance with the rules?
And what do you do after take off when you find out that the weather conditions at your destination are, in fact, 'worse' than the ones you'd planned on? I can envisage you flying around for 'a while' to burn fuel to reduce landing weight. Any other options?
(PS: Thanks, too, to 404T. Digesting your post now.)
I'm not confused about the difference between planning a flight and doing a flight. I have some exposure to and experience of the difference between forecast weather conditions and 'on paper' representations as to the conditions of a destination aerodrome, on the one hand, and dealing with reality on the other.
I'm confused about what and how you change things after you've taken off, having taken off at a weight calculated by reference to the conditions forecast before take off.
If you in fact "worked out pre-flight that you were limited [and you] reduced your fuel (tankering possibly) or payload", how do you increase fuel on board or passengers on board or cargo on board after take off, when you find out that the weather conditions at your destination are, in fact, 'better' than the ones you planned on? I can envisage you going a more direct route and landing with more fuel than planned, and therefore at a higher landing weight than planned. Any other way of landing heavier than planned, in accordance with the rules?
And what do you do after take off when you find out that the weather conditions at your destination are, in fact, 'worse' than the ones you'd planned on? I can envisage you flying around for 'a while' to burn fuel to reduce landing weight. Any other options?
(PS: Thanks, too, to 404T. Digesting your post now.)
Last edited by Lead Balloon; 7th Sep 2021 at 09:32.
I'm confused about what and how you change things after you've taken off, having taken off at a weight calculated by reference to the calculations before take off.
neville_nobody
And Air France into Toronto in the A340, though there was more to that accident than just LDR. The LDR was if memory serves me right, OK for the conditions. It was the persisting with an unstable approach and landing have way down 24L (9000 ft LDA) and delaying full reverse that caused them to go off the end. No amount of LDR calculations would have prevented that accident but it is the reason we are do thing the way we are now on the Airbus.
And Air France into Toronto in the A340, though there was more to that accident than just LDR. The LDR was if memory serves me right, OK for the conditions. It was the persisting with an unstable approach and landing have way down 24L (9000 ft LDA) and delaying full reverse that caused them to go off the end. No amount of LDR calculations would have prevented that accident but it is the reason we are do thing the way we are now on the Airbus.
Then I think we've circled back to Capn Bloggs's point.
Sounds like your company needs to configure Flysmart to be more user friendly 404-titan.
In my last company you didn’t have to do all that nonsense for wet runways etc., you just selected either dry or the amount of water on the runway (ability to choose either a wet or a contaminated runway basically).
In my last company you didn’t have to do all that nonsense for wet runways etc., you just selected either dry or the amount of water on the runway (ability to choose either a wet or a contaminated runway basically).
Thanks Lookleft.
I'm not confused about the difference between planning a flight and doing a flight. I have some exposure to and experience of the difference between forecast weather conditions and 'on paper' representations as to the conditions of a destination aerodrome, on the one hand, and dealing with reality on the other.
I'm confused about what and how you change things after you've taken off, having taken off at a weight calculated by reference to the conditions forecast before take off.
If you in fact "worked out pre-flight that you were limited [and you] reduced your fuel (tankering possibly) or payload", how do you increase fuel on board or passengers on board or cargo on board after take off, when you find out that the weather conditions at your destination are, in fact, 'better' than the ones you planned on? I can envisage you going a more direct route and landing with more fuel than planned, and therefore at a higher landing weight than planned. Any other way of landing heavier than planned, in accordance with the rules?
And what do you do after take off when you find out that the weather conditions at your destination are, in fact, 'worse' than the ones you'd planned on? I can envisage you flying around for 'a while' to burn fuel to reduce landing weight. Any other options?
(PS: Thanks, too, to 404T. Digesting your post now.)
I'm not confused about the difference between planning a flight and doing a flight. I have some exposure to and experience of the difference between forecast weather conditions and 'on paper' representations as to the conditions of a destination aerodrome, on the one hand, and dealing with reality on the other.
I'm confused about what and how you change things after you've taken off, having taken off at a weight calculated by reference to the conditions forecast before take off.
If you in fact "worked out pre-flight that you were limited [and you] reduced your fuel (tankering possibly) or payload", how do you increase fuel on board or passengers on board or cargo on board after take off, when you find out that the weather conditions at your destination are, in fact, 'better' than the ones you planned on? I can envisage you going a more direct route and landing with more fuel than planned, and therefore at a higher landing weight than planned. Any other way of landing heavier than planned, in accordance with the rules?
And what do you do after take off when you find out that the weather conditions at your destination are, in fact, 'worse' than the ones you'd planned on? I can envisage you flying around for 'a while' to burn fuel to reduce landing weight. Any other options?
(PS: Thanks, too, to 404T. Digesting your post now.)
Once you are airborne though, you obviously need to check based upon the exact conditions etc.
Unlike 404, I’ve never had Flysmart throw me up a greater LDR than the preflight 1.67/1.92, it’s generally just a bit less. But it’s not often that I’ve been that limited to the point of not being able to land at MLW either, normally been well in excess. Perhaps it’s in how they’ve got him figuring it out, because Flysmart is very customisable for the customer, case in point with the ability to select the level of contamination on the runway.
At the end of the day, this is very Australian, arguing over the semantics of this bull**** in this day and age of EFB’s. The rest of the world probably couldn’t give 2 ****s about how it’s worked out etc., they just punch it into the EFB, let it work it’s magic, and carry on with the rest of the day. When we do it day in and day out, I’d rather just show up at work and if it’s within the regs, who cares.
Good point!
Morno
It's stock standard Airbus. Been like this for a number of years though it's changed a little with FlySmart on the iPad EFB and the built in EFB on the A350 OIS. Prior to iPads etc, we'd use ACARS that had numbers from 6 for Dry to 1 for Ice (Poor). The new system is extremely easy and if you're not sure of the braking action there is a very easy table in the QRH. Everything is now standard Airbus. Lawyers have put an end to airlines doing there own thing and for this particular thing I agree. Before it was a dogs breakfast to the point a in-flight landing performance wasn't even required most of the time.
It's stock standard Airbus. Been like this for a number of years though it's changed a little with FlySmart on the iPad EFB and the built in EFB on the A350 OIS. Prior to iPads etc, we'd use ACARS that had numbers from 6 for Dry to 1 for Ice (Poor). The new system is extremely easy and if you're not sure of the braking action there is a very easy table in the QRH. Everything is now standard Airbus. Lawyers have put an end to airlines doing there own thing and for this particular thing I agree. Before it was a dogs breakfast to the point a in-flight landing performance wasn't even required most of the time.
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Another interesting regulatory anomaly would be if the same F100 was operating to Newman that day in the charter category, which occurs, it would only need to apply the 1.67 pre-dispatch factoring regardless of the wet runway.
I understand the new regs will fix that?
I understand the new regs will fix that?
Morno
It's stock standard Airbus. Been like this for a number of years though it's changed a little with FlySmart on the iPad EFB and the built in EFB on the A350 OIS. Prior to iPads etc, we'd use ACARS that had numbers from 6 for Dry to 1 for Ice (Poor). The new system is extremely easy and if you're not sure of the braking action there is a very easy table in the QRH. Everything is now standard Airbus. Lawyers have put an end to airlines doing there own thing and for this particular thing I agree. Before it was a dogs breakfast to the point a in-flight landing performance wasn't even required most of the time.
It's stock standard Airbus. Been like this for a number of years though it's changed a little with FlySmart on the iPad EFB and the built in EFB on the A350 OIS. Prior to iPads etc, we'd use ACARS that had numbers from 6 for Dry to 1 for Ice (Poor). The new system is extremely easy and if you're not sure of the braking action there is a very easy table in the QRH. Everything is now standard Airbus. Lawyers have put an end to airlines doing there own thing and for this particular thing I agree. Before it was a dogs breakfast to the point a in-flight landing performance wasn't even required most of the time.
I can’t say I was involved in setting up Flysmart in my company, so I’m not 100% sure how they did it. But I do know that it was different between 2 companies I’ve worked for, and apparently it’s just a matter of selecting certain things in the background before the end users (us) see it.
Perhaps try thinking about it like this:
The purpose of the dispatch calculation is to help determine the maximum weight for take-off, which must be the lesser of:
a. the take-off performance limited weight, and
b. the landing performance limited weight plus the weight of fuel/oil consumed in-flight.
The landing distance limited weight derived during that process is based on a bunch of regulatory factors and forecast conditions that are not particularly relevant for the actual landing. What's relevant are the actual conditions, weight, braking method, configuration, etc. The pilot uses that information to calculate the actual landing distance and factors it by 15% to determine the required landing distance. He or she can then compare the required distance with the distance available, to determine how much margin is available for the landing.
The following is an Airbus discussion of in-flight landing distance assessment:
https://safetyfirst.airbus.com/app/t...-distances.pdf
The purpose of the dispatch calculation is to help determine the maximum weight for take-off, which must be the lesser of:
a. the take-off performance limited weight, and
b. the landing performance limited weight plus the weight of fuel/oil consumed in-flight.
The landing distance limited weight derived during that process is based on a bunch of regulatory factors and forecast conditions that are not particularly relevant for the actual landing. What's relevant are the actual conditions, weight, braking method, configuration, etc. The pilot uses that information to calculate the actual landing distance and factors it by 15% to determine the required landing distance. He or she can then compare the required distance with the distance available, to determine how much margin is available for the landing.
The following is an Airbus discussion of in-flight landing distance assessment:
https://safetyfirst.airbus.com/app/t...-distances.pdf
Morno
It's not so much that FlySmart throughs it up. It's more that we ask it as it's and SOP requirement if we want to use idle reverse on a wet runway. Asking it to calculate a landing performane for Medium-Poor braking is the same as calculating a landing performance for a contaminated runway with more than 3mm of water or slush up to 13mm. In this calculation with the 1.15, it's more than the 1.67 and 1.92 dispatch calculation. Calculations for Dry and Good will be less than the pre Dispatch calculations.
Unlike 404, I’ve never had Flysmart throw me up a greater LDR than the preflight 1.67/1.92
If it is pxssing rain with a strong crosswind on a tapered runway (banking the water on one side of the runway) with no grooving then the runway may well be contaminated with poor braking. ALL of the pre-mentioned factors go out the window and you either hold or divert. A reputable ops manual might state that landing on a contaminated runway shall not be attempted unless a greater emergency exists...