TAP extra long landing
I used to go into Funchal regularly with Air Europe in the Boeing 737/200 and then the Boeing 757. It didn't use the 757 for Funchals until November 1985, over 2 years after it's introduction. I was one of the first to be checked out into Funchal in November 27th 1985 and cannot remember any real frights on the short runway. The 757 had a better take off performance the the 737 and all our Manchester and Gatwick fiights were non stop. Landings were Captain only, but First Officers were allowed to do the take-offs, which were the most frightening part of the operation!
I used to go into Funchal regularly with Air Europe in the Boeing 737/200 and then the Boeing 757. It didn't use the 757 for Funchals until November 1985, over 2 years after its introduction. I was one of the first to be checked out into Funchal in November 27th 1985 and cannot remember any real frights on the short runway. The 757 had a better take off performance than the 737, and all our Manchester and Gatwick flights were non stop. Landings were Captain only, but First Officers were allowed to do the take-offs, which were the most frightening part of the operation!
FNC was 1600m up until 1986, then 200m was added.
I have just had a spanner thrown in the works, that BIA British Island Airways may have taken their shiny new MD-83's in there from 1988 (1800m runway) ---->
More digging!
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As many of the airline pilots who actually have posted have stated ITS NOT THE BLOODY POINT! You have a TDZ and a certain latitude either side of it. Its what the landing figures are predicated on. and its what any half decent airline pilot should be able to achieve. What this video shows is a crew who have put the fate of their lives and that of the passengers in the laws of physics as they have left SOPS, skill and any sense of professionalism way, way behind them. They have decided to become test pilots and have bought the pax along for the ride. Runway excursions continue to be a problem and the reluctance to go-around is a good reason why. The only point that you are committed to the landing is when the thrust reversers have deployed. The sad reality is, probably this crew were more concerned about doing a go-around than they were running off the end. They more than likely thought that there was enough room to stop but had no numbers, technique or SOPs on which to base that decision on. All they had were wide eyes and four feet on the brake pedals.
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And that is the problem. I have flown maybe 10000 flights total in all those years. There are 100000 flights per DAY. If all of us would take what we perceive as an acceptable risk once a year, and it goes wrong 1% of the time, it would still lead to an unacceptable raise in the number of crashes..
as 1sothernman just said
I'd like to think somebody said in a quite moment on tax in or at the pub debrief "ya know we shoulda GA "...
As many of the airline pilots who actually have posted have stated ITS NOT THE BLOODY POINT! You have a TDZ and a certain latitude either side of it. Its what the landing figures are predicated on. and its what any half decent airline pilot should be able to achieve. What this video shows is a crew who have put the fate of their lives and that of the passengers in the laws of physics as they have left SOPS, skill and any sense of professionalism way, way behind them. They have decided to become test pilots and have bought the pax along for the ride. Runway excursions continue to be a problem and the reluctance to go-around is a good reason why. The only point that you are committed to the landing is when the thrust reversers have deployed. The sad reality is, probably this crew were more concerned about doing a go-around than they were running off the end. They more than likely thought that there was enough room to stop but had no numbers, technique or SOPs on which to base that decision on. All they had were wide eyes and four feet on the brake pedals.
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Again, there is no 'data' one needs to see, the aircraft landed outside of the TDZ, the die is cast with regards to culpability, unless for some incredibly unusual set of circumstances which would be basically limited to the aircraft being on fire or having <600kgs of fuel remaining. This video (to this competent observer) can be little more than a video of a flight crew failing to safely execute their duties at a very risky and complex airport.
Without the data it all basically speculation although yes, the video does not looks too good.
My other point was about throwig the SOPs as the ultimate proof they were wrong. , We all have navigated outside from time to time on certain types of operations especially operating in funny places.
I'd like to think somebody said in a quite moment on tax in or at the pub debrief "ya know we shoulda GA ".
Some are saying because they got away with it no damage done. The discussion should be around why the landing was persisted with in the first place. Why would a crew ignore all the red flags for a runway excursion and "press on" to an uncertain outcome. Is it training, standards or are there lots of pilots out there who would have done exactly the same thing in the same circumstances?
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I am not saying this landing was well executed, far from it, but those who advocate TDZ or else.... There is really only one touch down point which for which you have valid performance, and under certain runway conditions that performance is a best guess. If I remember correctly, runways > 2400 meters has TDZ markings for 900 meters without account for the length of the actual stripes. Is landing at the end of the TDZ more okay on a (relatively) short and slippery runway, than landing outside of the touchdown zone on a long dry runway, irresepective of aircraft type or weight? Somewhere you have to draw the line and the TDZ markings are good help to make that decision. I just have a gut feeling that those who don't recognize the above mentioned variables are also those that advocate 2 white 2 red or else....
Originally Posted by Lookleft
''Some are saying because they got away with it no damage done. The discussion should be around why the landing was persisted with in the first place.
Why would a crew ignore all the red flags for a runway excursion and "press on" to an uncertain outcome.
Is it training, standards or are there lots of pilots out there who would have done exactly the same thing in the same circumstances?''
The reading of the CVR readout of the TAP 425 B727-282 CS-TBR accident (overrun) in Nov 1977 is a sobering and sad document, and that 'We Must Get it in' mode cost the lives of 125 passengers and 6 crew members.
Shortly before 10pm on that Saturday evening, after 13 hours and 15 minutes of crew hours duty time, the very tired crew was trying to land their 727 on the difficult Madeira airport runway, which at the time was just 1,600 m (5,250 ft) long.
The first attempt to approach the runway had to be aborted because the crew was unable to establish visual contact with the runway. A second attempt was made, but again, had to be discontinued due to the poor visibility.
The Captain João Lontrão and Co-pilot Miguel Guimarães Leal decided to make one last try to land the plane before they would have to make the decision to divert to the Gando Gran Canaria Airport in the Canary Islands (Seems the nearer airport on the island of Porto Santo was not the Alternate)
While descending now to runway 24 on an NDB approach, the crew still encountered poor weather conditions with limited visibility to 3 km, clouds down to 1,500 feet with heavy rain showers.
A few minutes later, on the third attempt to land at a speed of Vref + 19 knots, the crew landed with too long a flare, and touched down too far down on runway 24, about 2,060 feet past the runway threshold (Runway 24 is 5,000 feet long) at a speed of 148 knots.
Immediately after touchdown, the crew activated the thrust reversers and deployed the spoilers but were unable to stop on the wet runway, and the 727 overran at 48 knots. It went down a steep embankment, collided with a stone bridge, broke into several pieces and eventually came to rest in flames on the beach located about 40 meters below airfield elevation.
The aircraft was totally destroyed by impact forces and a post crash fire.
Six crew members and 125 passengers were killed while 33 other occupants were seriously injured.
The investigation found lacking at Madeira Airport and had insufficient lights, making it difficult to perform an Approach.
Apart from the severe weather conditions at the time of landing, investigators looked at the crew’s Approach procedure. The accident report concluded that the crew touched down 1,060 feet (320 m) farther down the runway than they were meant to, at a speed that was 19.2 knots greater than recommended.
This, paired with the wet runway conditions that led to aquaplaning, sent TAP Flight 425 to its ultimate end.
In the wake of the accident, TAP replaced using its Boeing 727-28s with 727-82s on the route to Madeira.
This shorter variant, carried 60 fewer passengers – and was more suitable for landing on the short FNC runway, on which it had previously been operating from 1967, prior to the bigger 727-282 version delivered to TAP in 1975.
The airfield, originally known as Santa Catarina, had the 1600m runway, but the rest of the airport facilities were initially rather basic.
The first aircraft to arrive at the newly completed airport on Madeira was a TAP - Transportes Aéreos Portugueses Lockheed L-1049 Super Constellation, carrying 80 passengers on July 18, 1964.
A new passenger Terminal capable of handling 500,000 travellers per year opened in 1972 but local geography limited the length of the airstrip and growth was sluggish.
Funchal (FNC) soon gained a reputation as one of the most hazardous airfields in the world – due in part to its short runway but also because winds came off the sea and up the mountainside on which the airfield was constructed, as well as down nearby valleys.
The TAP 727 crash also spurred officials to look at extending the runway.
Construction for a (200-metre) extension began in 1983.
It took almost ten years, but in 1986 a 656ft (200m) extension was completed on the only remaining piece of flat land at the end of the airfield.
But it was still rather short for the then upcoming generation of new jets, and research set out to establish whether further lengthening might be possible and how it could be done.
The main alternate for Funchal is Porto Santo Airport (PXO), 60 miles (100km) and just a few minutes’ flying time across the archipelago. It has a 9,843ft (3,000m) runway but only six parking positions for airliners – 19 is the maximum that FNC can accommodate today, so PXO can get full quickly during periods of adverse weather.
If a diversion to PXO is not possible the Canary Islands are around 250 miles (400km) to the south,
Agadir and Casablanca, Morocco are both around 500 miles (800 km) to the east, and Lisbon 600 miles (965 km) to the northwest.
Each airline has its own procedures and nominates its own alternates.
Jeppesen chart for Madeira --- NOT up to date
Wind is not the only ‘gotcha’ though.
Poor visibility can be a problem, especially when the cloud base is low or easterly winds drag sand dust off the Sahara.
''Some are saying because they got away with it no damage done. The discussion should be around why the landing was persisted with in the first place.
Why would a crew ignore all the red flags for a runway excursion and "press on" to an uncertain outcome.
Is it training, standards or are there lots of pilots out there who would have done exactly the same thing in the same circumstances?''
The reading of the CVR readout of the TAP 425 B727-282 CS-TBR accident (overrun) in Nov 1977 is a sobering and sad document, and that 'We Must Get it in' mode cost the lives of 125 passengers and 6 crew members.
Shortly before 10pm on that Saturday evening, after 13 hours and 15 minutes of crew hours duty time, the very tired crew was trying to land their 727 on the difficult Madeira airport runway, which at the time was just 1,600 m (5,250 ft) long.
The first attempt to approach the runway had to be aborted because the crew was unable to establish visual contact with the runway. A second attempt was made, but again, had to be discontinued due to the poor visibility.
The Captain João Lontrão and Co-pilot Miguel Guimarães Leal decided to make one last try to land the plane before they would have to make the decision to divert to the Gando Gran Canaria Airport in the Canary Islands (Seems the nearer airport on the island of Porto Santo was not the Alternate)
While descending now to runway 24 on an NDB approach, the crew still encountered poor weather conditions with limited visibility to 3 km, clouds down to 1,500 feet with heavy rain showers.
A few minutes later, on the third attempt to land at a speed of Vref + 19 knots, the crew landed with too long a flare, and touched down too far down on runway 24, about 2,060 feet past the runway threshold (Runway 24 is 5,000 feet long) at a speed of 148 knots.
Immediately after touchdown, the crew activated the thrust reversers and deployed the spoilers but were unable to stop on the wet runway, and the 727 overran at 48 knots. It went down a steep embankment, collided with a stone bridge, broke into several pieces and eventually came to rest in flames on the beach located about 40 meters below airfield elevation.
The aircraft was totally destroyed by impact forces and a post crash fire.
Six crew members and 125 passengers were killed while 33 other occupants were seriously injured.
The investigation found lacking at Madeira Airport and had insufficient lights, making it difficult to perform an Approach.
Apart from the severe weather conditions at the time of landing, investigators looked at the crew’s Approach procedure. The accident report concluded that the crew touched down 1,060 feet (320 m) farther down the runway than they were meant to, at a speed that was 19.2 knots greater than recommended.
This, paired with the wet runway conditions that led to aquaplaning, sent TAP Flight 425 to its ultimate end.
In the wake of the accident, TAP replaced using its Boeing 727-28s with 727-82s on the route to Madeira.
This shorter variant, carried 60 fewer passengers – and was more suitable for landing on the short FNC runway, on which it had previously been operating from 1967, prior to the bigger 727-282 version delivered to TAP in 1975.
The airfield, originally known as Santa Catarina, had the 1600m runway, but the rest of the airport facilities were initially rather basic.
The first aircraft to arrive at the newly completed airport on Madeira was a TAP - Transportes Aéreos Portugueses Lockheed L-1049 Super Constellation, carrying 80 passengers on July 18, 1964.
A new passenger Terminal capable of handling 500,000 travellers per year opened in 1972 but local geography limited the length of the airstrip and growth was sluggish.
Funchal (FNC) soon gained a reputation as one of the most hazardous airfields in the world – due in part to its short runway but also because winds came off the sea and up the mountainside on which the airfield was constructed, as well as down nearby valleys.
The TAP 727 crash also spurred officials to look at extending the runway.
Construction for a (200-metre) extension began in 1983.
It took almost ten years, but in 1986 a 656ft (200m) extension was completed on the only remaining piece of flat land at the end of the airfield.
But it was still rather short for the then upcoming generation of new jets, and research set out to establish whether further lengthening might be possible and how it could be done.
The main alternate for Funchal is Porto Santo Airport (PXO), 60 miles (100km) and just a few minutes’ flying time across the archipelago. It has a 9,843ft (3,000m) runway but only six parking positions for airliners – 19 is the maximum that FNC can accommodate today, so PXO can get full quickly during periods of adverse weather.
If a diversion to PXO is not possible the Canary Islands are around 250 miles (400km) to the south,
Agadir and Casablanca, Morocco are both around 500 miles (800 km) to the east, and Lisbon 600 miles (965 km) to the northwest.
Each airline has its own procedures and nominates its own alternates.
Jeppesen chart for Madeira --- NOT up to date
Wind is not the only ‘gotcha’ though.
Poor visibility can be a problem, especially when the cloud base is low or easterly winds drag sand dust off the Sahara.
Last edited by rog747; 9th Jul 2023 at 16:23.
MD-83 FNC >?
An ex BIA British Island Airways skipper just sent me this - >>>
''We were unable to take the MD-83 there. The Vmcg was too high. For the non-drivers (airframe), that was the minimum speed you could control the a/c on the ground following an engine failure. In other words, approaching that speed you could neither stop or go on Funchal’s short runway following said engine failure - enough to spoil your whole day 😧😧😧
I took a 1-11 there twice. A very interesting exercise!
As Peter (Villa) said, we had to hop into Porto Santo for fuel''
Best R.
My two cents.
Some have mentioned that if you miss the TDZ, then that is a mandatory balked landing. That is in some airlines, not necessarily true. Nevertheless at a minimum you must at least know what the margin of distance is in the event that you miss the TDZ.
For example, on FLYSMART as part of the briefing, you are well served to make note that we have 285 metre of margin should we miss the touchdown zone.
At least then you know roughly what’s a stake.
Some have mentioned that if you miss the TDZ, then that is a mandatory balked landing. That is in some airlines, not necessarily true. Nevertheless at a minimum you must at least know what the margin of distance is in the event that you miss the TDZ.
For example, on FLYSMART as part of the briefing, you are well served to make note that we have 285 metre of margin should we miss the touchdown zone.
At least then you know roughly what’s a stake.
Only half a speed-brake
FlySmart, paved to hell is the road with good intentions.
The biggest challenge is learning to overcome the tunnel vision so that you have the capacity to push the levers forward and pull the nose up again.
For various scientific reasons, floating over the last TDZ markers can be your very last straw to refocus on what is the only good option.
Who dares to think otherwise, please remind me what is the punishment for going missed?
The biggest challenge is learning to overcome the tunnel vision so that you have the capacity to push the levers forward and pull the nose up again.
For various scientific reasons, floating over the last TDZ markers can be your very last straw to refocus on what is the only good option.
Who dares to think otherwise, please remind me what is the punishment for going missed?
Willie, "… you must at least know what the margin of distance is in the event that you miss the TDZ."
You appear to misunderstand or incorrectly define TDZ.
The 'TDZ' (fixed distance runway markings) is not related to actual runway length, thus there is no relationship with the aircraft landing performance, which is based on the LDA and local conditions (LDR).
The TDZ should not be confused with, or replace the expected touchdown position.
The distance safety margin is applied to counter many unknowns or variables in the computation; it is not for the crew to 'use'.
Because there is no relationship between TDZ and the stop end of the runway, it is not possible to be assured that the remaining runway distance will be sufficient to stop the aircraft.
FD
You appear to misunderstand or incorrectly define TDZ.
The 'TDZ' (fixed distance runway markings) is not related to actual runway length, thus there is no relationship with the aircraft landing performance, which is based on the LDA and local conditions (LDR).
The TDZ should not be confused with, or replace the expected touchdown position.
The distance safety margin is applied to counter many unknowns or variables in the computation; it is not for the crew to 'use'.
Because there is no relationship between TDZ and the stop end of the runway, it is not possible to be assured that the remaining runway distance will be sufficient to stop the aircraft.
FD
The 'TDZ' (fixed distance runway markings) is not related to actual runway length, thus there is no relationship with the aircraft landing performance, which is based on the LDA and local conditions (LDR).
The TDZ should not be confused with, or replace the expected touchdown position.
The TDZ should not be confused with, or replace the expected touchdown position.
Air Run Distance from threshold to touchdown is associated with a flare time of 7 seconds.
Provided your runway is marked IAW ICAO, you will, beforehand, know where the 7sec point is WRT the markings. It is therefore easy to ascertain if you will/have touched down in the "TDZ".
For example, on FLYSMART as part of the briefing, you are well served to make note that we have 285 metre of margin should we miss the touchdown zone.
I don't fly the A320 but I assume the certification requirements are similar (ie 7sec to touch). If the aeroplane isn't touching down by the 450m markers/point (~7sec), you're now eating into your predicted landing distance. This is all regardless of the LDA.
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Allthough I agree that it was poor airmanship and a goaround was in order, goal fixation combined with startle effect makes mistakes like this happend. I don`t think Tea and Bicuits are required if the company has a good Safety Management System with none punitive reporting. If pilots report their mistakes and show willingness to learn there should be no punitive actions, if not though might call them for a visit to the office.
Last edited by H. Hughes; 15th Jul 2023 at 13:14. Reason: Typo
If you look at this event using the FAiR system (used by many safety departments) and with the following assumption:
- TAP Policy is a go around shall be conducted if the aircraft does not touch down in the TDZ
it is very hard to assess this event as anything other than recklessness which places the event on the boundary between retraining/administrative action and disciplinary action. A proper Just Culture provides for both of the above. Filing an ASR after the event does not equate to a free pass from negligence on the day though it would clearly be seen as mitigation when flight ops are reviewing the event.
- TAP Policy is a go around shall be conducted if the aircraft does not touch down in the TDZ
it is very hard to assess this event as anything other than recklessness which places the event on the boundary between retraining/administrative action and disciplinary action. A proper Just Culture provides for both of the above. Filing an ASR after the event does not equate to a free pass from negligence on the day though it would clearly be seen as mitigation when flight ops are reviewing the event.
Who dares to think otherwise, please remind me what is the punishment for going missed?
I remember having to explain my fuel load. Said —- thought that even if Porto Santo parking was full. Just land & stay on the Runway. i.e No excuse for taking Canary diversion fuel.
Hopefully that type of pressure is long gone.
Terminology, definition, viewpoint
The crux of the discussion involves differing definitions, and how theory is related to practice.
There are many regulatory and other guidance documents requiring update after the TALPA changes (operational landing distances).
"The 'TDZ' (fixed distance runway markings) is not related to actual runway length, thus there is no relationship with the aircraft landing performance, …."
In this sense TDZ is defined as a marked distance along the runway which can be identified but not related directly to expected performance.
Alternatively, 'Touchdown Zone' as an idealistic area in which the pilot aims to touchdown; the position is only identified after a landing, where aircraft actually touchdown. It involves air distance - a variable, and other variations including piloting techniques. The touchdown position is important in landing performance, but never fully assured as a fixed point. cf aerial photos of dispersion of rubber markings.
Landing performance is assessed using reported conditions; many factors are variable, e.g. reported wind (+-2), vs actual headwind (+-?) n.b Funchal, may need more than the minimum 15% safety margin.
The derivation of landing performance is in AMC CS 25.1592.
Para 3.0 lists 'standard assumptions' which contribute to variability. Note paras 5.0 and 6.0 … [page 28 …]
" … assessing the landing performance at the time of arrival using procedures for operation in service. These procedures should: — be able to be consistently executed in service by flight crews of average skill; — include safe and reliable methods or devices; and — allow for any time delays that may reasonably be expected in service.
The air distance that is used for any landing at any runway is a function of the following variables: — runway approach guidance; — runway slope; — use of any aeroplane features or equipment (e.g. heads-up guidance, auto-flight systems, etc.); — pilot technique; and — the inherent flare characteristics of the aeroplane.
… analytically determine the air distance that is used for operational assessments of the landing performance as ‘the distance that is traversed over a period of 7 sec at a speed of 98 % of the recommended speed above the landing threshold’.
The recommended ‘speed above the landing threshold’ may also be referred to as the ‘final-approach speed (VAPP)’. The above air distance represents a flare time of 7 sec and a touchdown speed (VTD) of 96 % of the VAPP. The VAPP should be consistent with the procedures recommended including any speed additives, e.g. those that may be used due to winds or icing conditions.
… also provide the effects of higher speeds, to account for variations that occur in operations or are caused by the operating procedures of individual operators."
The realty of operations is indicated in an FAA study of landing performance; note the range of values, section 4.3 onwards [page 28 …].
The key influencing factors are also in FAA AC 91-79 Mitigating the Risks of a Runway Overrun Landings.
Aircraft landing distance is not related to TDZ; it could with calculation dependant on specific conditions, but never assured due to the situational variabilities and pilot performance.
Beware SOPs based on TDZ runway markings - exceptions for specific runways with special markings e.g Vagar EKVG 'Touchdown in the yellow box, LCY before the fixed line \ lights'.
AMC CS 25.1592, page 26 … https://www.easa.europa.eu/en/downloads/134260/en
FAA A Study of Normal Operational Landing Performance on Subsonic, Civil, Narrow-Body Jet Aircraft; page 29 … https://www.tc.faa.gov/its/worldpac/techrpt/ar077.pdf 5 M/s ≈ 10kts
AC 91-79 Mitigating the Risks of a Runway Overrun Upon Landing https://skybrary.aero/sites/default/...shelf/3606.pdf
ICAO Doc 10064 - Aeroplane Performance Manual, page 12 … and particularly the Appendices https://www.sapoe.org/wp-content/upl...Task-Force.pdf
There are many regulatory and other guidance documents requiring update after the TALPA changes (operational landing distances).
"The 'TDZ' (fixed distance runway markings) is not related to actual runway length, thus there is no relationship with the aircraft landing performance, …."
In this sense TDZ is defined as a marked distance along the runway which can be identified but not related directly to expected performance.
Alternatively, 'Touchdown Zone' as an idealistic area in which the pilot aims to touchdown; the position is only identified after a landing, where aircraft actually touchdown. It involves air distance - a variable, and other variations including piloting techniques. The touchdown position is important in landing performance, but never fully assured as a fixed point. cf aerial photos of dispersion of rubber markings.
Landing performance is assessed using reported conditions; many factors are variable, e.g. reported wind (+-2), vs actual headwind (+-?) n.b Funchal, may need more than the minimum 15% safety margin.
The derivation of landing performance is in AMC CS 25.1592.
Para 3.0 lists 'standard assumptions' which contribute to variability. Note paras 5.0 and 6.0 … [page 28 …]
" … assessing the landing performance at the time of arrival using procedures for operation in service. These procedures should: — be able to be consistently executed in service by flight crews of average skill; — include safe and reliable methods or devices; and — allow for any time delays that may reasonably be expected in service.
The air distance that is used for any landing at any runway is a function of the following variables: — runway approach guidance; — runway slope; — use of any aeroplane features or equipment (e.g. heads-up guidance, auto-flight systems, etc.); — pilot technique; and — the inherent flare characteristics of the aeroplane.
… analytically determine the air distance that is used for operational assessments of the landing performance as ‘the distance that is traversed over a period of 7 sec at a speed of 98 % of the recommended speed above the landing threshold’.
The recommended ‘speed above the landing threshold’ may also be referred to as the ‘final-approach speed (VAPP)’. The above air distance represents a flare time of 7 sec and a touchdown speed (VTD) of 96 % of the VAPP. The VAPP should be consistent with the procedures recommended including any speed additives, e.g. those that may be used due to winds or icing conditions.
… also provide the effects of higher speeds, to account for variations that occur in operations or are caused by the operating procedures of individual operators."
The realty of operations is indicated in an FAA study of landing performance; note the range of values, section 4.3 onwards [page 28 …].
The key influencing factors are also in FAA AC 91-79 Mitigating the Risks of a Runway Overrun Landings.
Aircraft landing distance is not related to TDZ; it could with calculation dependant on specific conditions, but never assured due to the situational variabilities and pilot performance.
Beware SOPs based on TDZ runway markings - exceptions for specific runways with special markings e.g Vagar EKVG 'Touchdown in the yellow box, LCY before the fixed line \ lights'.
AMC CS 25.1592, page 26 … https://www.easa.europa.eu/en/downloads/134260/en
FAA A Study of Normal Operational Landing Performance on Subsonic, Civil, Narrow-Body Jet Aircraft; page 29 … https://www.tc.faa.gov/its/worldpac/techrpt/ar077.pdf 5 M/s ≈ 10kts
AC 91-79 Mitigating the Risks of a Runway Overrun Upon Landing https://skybrary.aero/sites/default/...shelf/3606.pdf
ICAO Doc 10064 - Aeroplane Performance Manual, page 12 … and particularly the Appendices https://www.sapoe.org/wp-content/upl...Task-Force.pdf