Hints on landing performance
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From: Australia
Hints on landing performance
I recall a thread on aircraft landing performance that gave useful reminders such as 10% excess airspeed (over Vref) increases landing distance by more than 20% There were similar aide-memoir warnings covering other aspects of aircraft performance that I cannot recall. It would be appreciated if anyone else can list them here.
Joined: Dec 2002
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From: UK
~ page 37
https://www.faa.gov/documentLibrary/...91-79B_FAA.pdf
best to understand the basis of the performance, and focus on the initial situation assessment and judgement to minimise surprises; your choice of additional safety margin
https://safetyfirst.airbus.com/app/t...-distances.pdf
Appx 9 and other items
https://www.sapoe.org/wp-content/upl...rce.pdf#page60
https://www.faa.gov/documentLibrary/...91-79B_FAA.pdf
best to understand the basis of the performance, and focus on the initial situation assessment and judgement to minimise surprises; your choice of additional safety margin
https://safetyfirst.airbus.com/app/t...-distances.pdf
Appx 9 and other items
https://www.sapoe.org/wp-content/upl...rce.pdf#page60
Joined: Mar 2012
Posts: 118
Likes: 36
From: Somewhere
I recall a thread on aircraft landing performance that gave useful reminders such as 10% excess airspeed (over Vref) increases landing distance by more than 20% There were similar aide-memoir warnings covering other aspects of aircraft performance that I cannot recall. It would be appreciated if anyone else can list them here.
At that moment, you should also consider your height over the threshold.If you cross the threshold higher than normal, the additional landing distance can be roughly estimated as 1 foot for every 6 meters. 1:6
For example, if you cross the threshold at 100 feet, you’ll need about 50 × 6 = 300 meters more runway than what was calculated before the approach.From this, you can quickly decide whether to continue the landing or go around.
Last edited by Noknoipobin; 14th October 2025 at 13:40.
Joined: Dec 2002
Posts: 2,775
Likes: 353
From: UK
Worry first, thus prepared
https://www.dropbox.com/scl/fi/pxdpj...=t3oz28kx&dl=0
https://www.dropbox.com/scl/fi/yim4p...=044hy7h7&dl=0
https://www.faa.gov/documentLibrary/...r/AC_25-32.pdf
https://www.faa.gov/sites/faa.gov/fi.../SAFO19001.pdf
"RCAM provides a means to predict landing performance but does not provide a way to validate that prediction."
"Pilot braking action reports are well known to be far too inaccurate and subjective for meaningful analysis."
Borrowed wisdom breaks under pressure because you haven't earned it. You're trusting someone else's comprehension without knowing what created it.
Earned wisdom, on the other hand, holds up because it's rooted in your actual experience. You know when it works, why it works, when to ignore it and when to bend it because you created the comprehension.
.
https://www.dropbox.com/scl/fi/yim4p...=044hy7h7&dl=0
https://www.faa.gov/documentLibrary/...r/AC_25-32.pdf
https://www.faa.gov/sites/faa.gov/fi.../SAFO19001.pdf
"RCAM provides a means to predict landing performance but does not provide a way to validate that prediction."
"Pilot braking action reports are well known to be far too inaccurate and subjective for meaningful analysis."
Borrowed wisdom breaks under pressure because you haven't earned it. You're trusting someone else's comprehension without knowing what created it.
Earned wisdom, on the other hand, holds up because it's rooted in your actual experience. You know when it works, why it works, when to ignore it and when to bend it because you created the comprehension.
.
Last edited by safetypee; 15th October 2025 at 21:14.
Joined: Mar 2012
Posts: 118
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From: Somewhere
I didn’t mean that a height of 1 foot per 6 meters of distance is actually a 1:6 ratio.
It’s just a quick mental-calculation technique used during flight — since a pilot obviously can’t just stop the aircraft and grab a calculator like in a simulator or at home.
What it really means is that for every foot of altitude gained, you’ll use about 6 meters more of runway. That’s because most runway lengths around the world are measured in meters.
But if you’re flying in the U.S., you could use 1:20 instead.( 1foot height for 20 feet length )
Or if you really want to be exact, you could say 1:19.68 (from 6 meters convert to feet) or more accuracy 1:19.0838 (3 degree angle)
Are you a pilot, or a math teacher?I think a pilot would understand exactly what I’m talking about.
It’s just a quick mental-calculation technique used during flight — since a pilot obviously can’t just stop the aircraft and grab a calculator like in a simulator or at home.
What it really means is that for every foot of altitude gained, you’ll use about 6 meters more of runway. That’s because most runway lengths around the world are measured in meters.
But if you’re flying in the U.S., you could use 1:20 instead.( 1foot height for 20 feet length )
Or if you really want to be exact, you could say 1:19.68 (from 6 meters convert to feet) or more accuracy 1:19.0838 (3 degree angle)
Are you a pilot, or a math teacher?I think a pilot would understand exactly what I’m talking about.
Last edited by Noknoipobin; 16th October 2025 at 07:39.
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From: Bremen
Another hint:
At that moment, you should also consider your height over the threshold.If you cross the threshold higher than normal, the additional landing distance can be roughly estimated as 1 foot for every 6 meters. 1:6
For example, if you cross the threshold at 100 feet, you’ll need about 50 × 6 = 300 meters more runway than what was calculated before the approach.From this, you can quickly decide whether to continue the landing or go around.
At that moment, you should also consider your height over the threshold.If you cross the threshold higher than normal, the additional landing distance can be roughly estimated as 1 foot for every 6 meters. 1:6
For example, if you cross the threshold at 100 feet, you’ll need about 50 × 6 = 300 meters more runway than what was calculated before the approach.From this, you can quickly decide whether to continue the landing or go around.
In what kind of situation would you decide that on the go?
I imagine that when you prepare the approach, comparing LDA to LDR, you'd think about what margin you have, as in "I have 300m I don't need, so it's still ok if I come in 50 ft high" or something like that?
or do your company SOP define margins for "hot and high" which mandate a go-around if you exceed them?
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From: OZ
I think that the major factor in eating up runway is excess speed over the threshold. That is not to say that excess height is irrelevant, both matter. Kinetic energy is a V squared factor so it means a surprising increase in landing distance required especially in high density altitude situations where that is not necessarily obvious. Remember that TAS increases at roughly 2% per thousand feet so Mexico City can get exciting. I used to operate B707s through there, some interesting landings and heavy take offs.
Joined: Mar 2012
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From: Somewhere
Since there's a TDZ marker every 150m, that means each 25 ft more above the threshold means touching down one marker further along.
In what kind of situation would you decide that on the go?
I imagine that when you prepare the approach, comparing LDA to LDR, you'd think about what margin you have, as in "I have 300m I don't need, so it's still ok if I come in 50 ft high" or something like that?
or do your company SOP define margins for "hot and high" which mandate a go-around if you exceed them?
In what kind of situation would you decide that on the go?
I imagine that when you prepare the approach, comparing LDA to LDR, you'd think about what margin you have, as in "I have 300m I don't need, so it's still ok if I come in 50 ft high" or something like that?
or do your company SOP define margins for "hot and high" which mandate a go-around if you exceed them?
For example, suppose before the approach you calculate a landing distance of 2000 m, while the runway length is 2250 m or 2300 m — if you come in on the normal path, that’s no problem.But say that day you cross the threshold at 100 ft (when you’re over the threshold and the RA shows or calls out “100”). Should you still land? And what if the runway were 4000 m instead — your decision might be different.
If it is OK ,land- If it’s not,GA. You can either decide in advance how much you can exceed during the briefing, or just think about it when you’re over the threshold—either way, it’s the same principle I mentioned.
Without that kind of hint, how would you know how much the landing distance would increase?It’s probably not related to company policy — it’s just a hint, not an SOP.
Note: The runway length we actually land on might not have the same margin as in the preflight planning.It’s not always plenty of length available — for example, you might have to divert to any airport, and factors such as aircraft condition, weather, runway surface, and other elements could increase the landing distance to the point where there’s almost no margin left.
Yes, speed is important, but the person who started the thread has already mentioned that.I’m just giving another hint. If you have other hints, you can share them with him.
I say again it's a hint not an SOP.
Last edited by Noknoipobin; 16th October 2025 at 10:21.
Joined: Sep 2008
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From: 41S174E
Hi there Nok,
I like your hint, or ‘rule of thumb’, it helps with a broad understanding of the importance of crossing the threshold at a sensible height.
If you’ve calculated your landing distance at 2000m then you are in a pretty fast and heavy aeroplane.
I can see that the aircraft is quite sophisticated as well.
One thing I have noticed over the last few years is that when I’m sitting beside a person with relatively low flight experience, ( say 2000hrs) and we are crossing the threshold of the landing runway, they could do a nice job of the landing, and they could tell me what 3x7 equals, but they couldn’t do both at the same time.
When you are crossing the threshold it isn’t the time to try and determine your deviation from the 50 foot ideal and then make a simple mathematical calculation, and then use the answer to make a decision about whether to continue to land or conduct a missed approach. It’s simply too cumbersome.
But that is no problem because on 99% of landings in a big fast sophisticated aeroplane, you will have markings painted on the runway that give you good information about your runway performance. Most of the time you don’t want to touch down before the 1000 foot markings, you’d be fairly comfortable with touching down at the 1500 foot markings, and you’d be a bit disappointed in yourself if you landed on the 2000’ markings. Beyond the 2000 foot markings we are starting to get into more nuanced decision making conversations that will differ for each weight and each runway.
So although I like your rule of thumb regarding threshold crossing height, I think it best serves pilots as an easy way to articulate the importance of accurately flying the planned approach profile while they are sipping coffee in a classroom, and could be problematic if applied in real time.
I like your hint, or ‘rule of thumb’, it helps with a broad understanding of the importance of crossing the threshold at a sensible height.
For example, suppose before the approach you calculate a landing distance of 2000 m, while the runway length is 2250 m
when you’re over the threshold and the RA shows or calls out “100”
One thing I have noticed over the last few years is that when I’m sitting beside a person with relatively low flight experience, ( say 2000hrs) and we are crossing the threshold of the landing runway, they could do a nice job of the landing, and they could tell me what 3x7 equals, but they couldn’t do both at the same time.
When you are crossing the threshold it isn’t the time to try and determine your deviation from the 50 foot ideal and then make a simple mathematical calculation, and then use the answer to make a decision about whether to continue to land or conduct a missed approach. It’s simply too cumbersome.
But that is no problem because on 99% of landings in a big fast sophisticated aeroplane, you will have markings painted on the runway that give you good information about your runway performance. Most of the time you don’t want to touch down before the 1000 foot markings, you’d be fairly comfortable with touching down at the 1500 foot markings, and you’d be a bit disappointed in yourself if you landed on the 2000’ markings. Beyond the 2000 foot markings we are starting to get into more nuanced decision making conversations that will differ for each weight and each runway.
So although I like your rule of thumb regarding threshold crossing height, I think it best serves pilots as an easy way to articulate the importance of accurately flying the planned approach profile while they are sipping coffee in a classroom, and could be problematic if applied in real time.
Joined: Jan 2025
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From: New Zealand
Hi there Nok,
I like your hint, or ‘rule of thumb’, it helps with a broad understanding of the importance of crossing the threshold at a sensible height.
If you’ve calculated your landing distance at 2000m then you are in a pretty fast and heavy aeroplane.
I can see that the aircraft is quite sophisticated as well.
One thing I have noticed over the last few years is that when I’m sitting beside a person with relatively low flight experience, ( say 2000hrs) and we are crossing the threshold of the landing runway, they could do a nice job of the landing, and they could tell me what 3x7 equals, but they couldn’t do both at the same time.
When you are crossing the threshold it isn’t the time to try and determine your deviation from the 50 foot ideal and then make a simple mathematical calculation, and then use the answer to make a decision about whether to continue to land or conduct a missed approach. It’s simply too cumbersome.
But that is no problem because on 99% of landings in a big fast sophisticated aeroplane, you will have markings painted on the runway that give you good information about your runway performance. Most of the time you don’t want to touch down before the 1000 foot markings, you’d be fairly comfortable with touching down at the 1500 foot markings, and you’d be a bit disappointed in yourself if you landed on the 2000’ markings. Beyond the 2000 foot markings we are starting to get into more nuanced decision making conversations that will differ for each weight and each runway.
So although I like your rule of thumb regarding threshold crossing height, I think it best serves pilots as an easy way to articulate the importance of accurately flying the planned approach profile while they are sipping coffee in a classroom, and could be problematic if applied in real time.
I like your hint, or ‘rule of thumb’, it helps with a broad understanding of the importance of crossing the threshold at a sensible height.
If you’ve calculated your landing distance at 2000m then you are in a pretty fast and heavy aeroplane.
I can see that the aircraft is quite sophisticated as well.
One thing I have noticed over the last few years is that when I’m sitting beside a person with relatively low flight experience, ( say 2000hrs) and we are crossing the threshold of the landing runway, they could do a nice job of the landing, and they could tell me what 3x7 equals, but they couldn’t do both at the same time.
When you are crossing the threshold it isn’t the time to try and determine your deviation from the 50 foot ideal and then make a simple mathematical calculation, and then use the answer to make a decision about whether to continue to land or conduct a missed approach. It’s simply too cumbersome.
But that is no problem because on 99% of landings in a big fast sophisticated aeroplane, you will have markings painted on the runway that give you good information about your runway performance. Most of the time you don’t want to touch down before the 1000 foot markings, you’d be fairly comfortable with touching down at the 1500 foot markings, and you’d be a bit disappointed in yourself if you landed on the 2000’ markings. Beyond the 2000 foot markings we are starting to get into more nuanced decision making conversations that will differ for each weight and each runway.
So although I like your rule of thumb regarding threshold crossing height, I think it best serves pilots as an easy way to articulate the importance of accurately flying the planned approach profile while they are sipping coffee in a classroom, and could be problematic if applied in real time.
ROPS/ROWS does this on an on-the-fly basis.
Joined: Sep 2008
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From: 41S174E
I suspect that would end up with briefing a defined go-around point
