Air France crash at YYZ (Merged)
qsyenroute: Quite true. I can't remember reading about bad weather at an airport where the Approach or Tower Controller told an aircraft not to take off or land. Unless high winds frighten the guys/gals in the tower (as happened at Hartford "Windsor Locks" when they left-just before a large jet on a VOR approach scraped the trees on a hill 
), ATC is apparently NOT allowed to stop a takeoff or landing. Is it? Other than a truck or aircraft not sufficiently clear of a runway (or approach interval), this would be new to me.
Again, none of us know all of the facts concerning the accident at Toronto, and have no idea what information was available to the Air France crew. Each situation on departure/arrival which consists of convective weather is unique. Nobody can forecast the rate of increase or anything else. I've never experienced strong thunderstorms anywhere in Canada-although I have flown only a limited number of legs up there.
My previous remarks reflected my observations that years ago, Captains almost never seemed to ask FOs whether he/she did not like a worsening situation, i.e. increasingly uncomfortable turbulence in springtimer cells, or on a long glideslope with a line of weather (and on radar) which is coming towards the localizer. The first time I remember it was with a lady Captain on a Bandeirante and she did not want to return to the departure airport (plenty of fuel with ok weather behind us), I suppose, without asking if I found the chop unpleasant with more small bumpy clouds on radar in front of us. Who knows? Maybe CRM was created because male pilots don't want to admit certain feelings to others, or seek ideas (advice)??
They might not get lost as often when driving in a different city, but when it happens, they might around longer, especially seated next to a female.
), ATC is apparently NOT allowed to stop a takeoff or landing. Is it? Other than a truck or aircraft not sufficiently clear of a runway (or approach interval), this would be new to me.Again, none of us know all of the facts concerning the accident at Toronto, and have no idea what information was available to the Air France crew. Each situation on departure/arrival which consists of convective weather is unique. Nobody can forecast the rate of increase or anything else. I've never experienced strong thunderstorms anywhere in Canada-although I have flown only a limited number of legs up there.
My previous remarks reflected my observations that years ago, Captains almost never seemed to ask FOs whether he/she did not like a worsening situation, i.e. increasingly uncomfortable turbulence in springtimer cells, or on a long glideslope with a line of weather (and on radar) which is coming towards the localizer. The first time I remember it was with a lady Captain on a Bandeirante and she did not want to return to the departure airport (plenty of fuel with ok weather behind us), I suppose, without asking if I found the chop unpleasant with more small bumpy clouds on radar in front of us. Who knows? Maybe CRM was created because male pilots don't want to admit certain feelings to others, or seek ideas (advice)??
They might not get lost as often when driving in a different city, but when it happens, they might around longer, especially seated next to a female.
Last edited by Ignition Override; 11th Aug 2005 at 03:42.
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Dont give Authority to ATC
Dr Dave:
It is fairly clear surely that he/she is pointing out that similar accidents have been occurring for a long time, and that in his/her opinion a (partial?) remedy might be to give more authority to ATC?
Dont even think it....In Russia for a long time, and perhaps to this day, if you are not exactly on the profile ATC believevs you should be on on the approach they will tell you to G/A, even if the aircraft is exactly within its performance guidelines.
Many times on a slightly high on GS in full VMC I have ordered to G/A.....unfortunately my mic sometimes sticks when i am asking for a current wind check, and confirming that I may be permitted to use taxiway Z...and yes I am ready to land.....
Bumz
It is fairly clear surely that he/she is pointing out that similar accidents have been occurring for a long time, and that in his/her opinion a (partial?) remedy might be to give more authority to ATC?
Dont even think it....In Russia for a long time, and perhaps to this day, if you are not exactly on the profile ATC believevs you should be on on the approach they will tell you to G/A, even if the aircraft is exactly within its performance guidelines.
Many times on a slightly high on GS in full VMC I have ordered to G/A.....unfortunately my mic sometimes sticks when i am asking for a current wind check, and confirming that I may be permitted to use taxiway Z...and yes I am ready to land.....
Bumz
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It's probably been said earlier, maybe more than a dozen times.
If the aircraft had been on the ground in the TDZ, with tailwind within limits, it would have stopped on the runway.
If it wasn't on the ground in the TDZ, then it should have been a go around.
Even without brakes, or reverse, one or the other, it would have stopped, and the chances of both, all brake systems (three or more) and reverse thrust, failing are so remote it doesn't bear even a thought.
Eye witness reports indicate it didn't crash on the runway; it over ran the runway after a landing.
If QF1 had been on the runway at the correct point, even with the subsequent mishandling, it could have stopped. It landed long.
The only possible scenario is that it was not on the ground where it should have been with tailwind less than the specified maximum.
This is not an over simplification.
Most, or all, of us have done it but without such spectacular consequences.
If the aircraft had been on the ground in the TDZ, with tailwind within limits, it would have stopped on the runway.
If it wasn't on the ground in the TDZ, then it should have been a go around.
Even without brakes, or reverse, one or the other, it would have stopped, and the chances of both, all brake systems (three or more) and reverse thrust, failing are so remote it doesn't bear even a thought.
Eye witness reports indicate it didn't crash on the runway; it over ran the runway after a landing.
If QF1 had been on the runway at the correct point, even with the subsequent mishandling, it could have stopped. It landed long.
The only possible scenario is that it was not on the ground where it should have been with tailwind less than the specified maximum.
This is not an over simplification.
Most, or all, of us have done it but without such spectacular consequences.
Last edited by relax737; 11th Aug 2005 at 09:13.
Go Around into a Downburst
Relax737, as has been reported by myself and others, there was a severe thunderstorm west of rwy 24L heavier than any I can recall for several years. I doubt that a go around straight into that thunderstorm would have been successful.
I regret that I did not save the radar images that I observed in the time before the accident as they were quite impressive, especially how fast they were moving. The TSB did announce that they have engaged meteorological specialists to retrieve this data and will likely present it in the report.
There is a valid question about continuing an approach when there's a nasty, big, black cell sitting in the missed approach path which precludes the option for a go around.
I regret that I did not save the radar images that I observed in the time before the accident as they were quite impressive, especially how fast they were moving. The TSB did announce that they have engaged meteorological specialists to retrieve this data and will likely present it in the report.
There is a valid question about continuing an approach when there's a nasty, big, black cell sitting in the missed approach path which precludes the option for a go around.
Many of the issues questioned (and some answered) by ‘unprofessional’ posters, or by people who still wish to allocate blame; or even those who insist that they have done ‘it’ without undue problems, suggests that they all exhibit lack of knowledge of the situation, the technicalities of landing and stopping, or particularly of human vulnerability to error.
If we are to allocate blame (natural human behaviour), then we should consider blaming ourselves as part of the overall system that, when it fails, can lead to this type of accident.
Probably all of us have transgressed one or more of the landing parameters without problems, but how many realised how close the landing was to becoming a serious incident of even an accident.
1. Statistically we land fast (just check the FDM data); we tend to land long, or accept long landings in proportion to the length of the runway (SEMSA data).
2. We land on wet runways, but how wet is wet? The small difference between 2.5 mm and 3.1 mm of water is probably not detectable during operations, but increasing water depth has a significant effect on braking effectiveness? When does wet become contaminated – ‘wet with water patches ?’ – I have never heard a 'wet contaminated' report broadcast.
3. We have the perception that a grooved runway surface is more effective (JAR-OPS tells us so), but how do we know if the grooves are clear or blocked with rubber etc? Do we really understand the differences in friction between a good porous black top and the often quite low friction on concrete runways? Do we know how well drained the runway is, and even with good drainage it takes time to be effective which could be degraded in crosswinds (damming effect).
4. We often land in tailwinds, but do we actually know what change of wind occurs after the last wind check – and was the last ‘wind’ given on short final or 5 mins ago from ATIS.
5. Do we always know the actual touchdown speed, and where was the point of touchdown with respect to the optimum?
6. We land with Cbs in the vicinity of airports, but how many checks are made on short final to determine storm movement and current position? We may consider the threat of windshear when in the air and carry additional speed, but do we consider loosing that energy before or during landing; and what if the windshear hits when you are on the ground?
I suggest that few pilots actual know what all of the conditions are during a landing, thus it is futile to ask why didn’t a crew do that – because it is most probable that they did not know - no one else knew, no one told them, or the crew/others failed to observe or understand the relevance of the information they had.
Very few pilots actually know what safety margins remain during normal landings; those that do, should have some red annotated experiences in their flying logbook. (i.e. wet landing at LCY in a crosswind at night).
In many cases our lack of basic knowledge about aircraft performance fails to set an appropriate safety line. This can be degraded further by examples of poor operating practices from both our peers and our own behaviour, and a wide range of other human factors.
One of the human problems is that we tend to reset our safety line to the last ‘successful’ landing. Few of us conduct a self-debrief to consider what the actual margin of safety was, and ask ‘what would happen if’ any other parameter approached the limit and what would the consequences be. A debrief, self and with crew, is a powerful means of readjusting positively or reconfirming our personal safety limits on which the industry depends on.
Do we really consider any of the individual transgressions as a threat to safety? What happens if there were simultaneous transgressions - wet runway and tailwind; then what margin is there for error - incorrect wind, misread friction level, incorrect airspeed, long landing, windshear?
If you want blame, then we should blame ourselves.
However, we are able to change how we operate as individuals and we can influence others with positive examples, and if we see an uncontrolled threat then we can report it e.g. slick surface, large quantities of paint / rubber / de-icing fluid on the runway.
For those other, rare circumstances, then we have to respect the weather and be aware of our and others fallibility. With two or more transgressions (amber alerts) do we promote the threat to a red warning level and follow TEM rule 1:- Avoid the threats.
We can and must improve knowledge and thus our own professionalism throughout our career. This is not the forum for the unprofessional or the “I can do’ers”, but for those who wish to learn then let us have an open and educating exchange of information.
Errors in aviation decision making.
How good pilots make bad decisions.
Managing threats
--------------------
Unless specifically authorized everything else is forbidden.
If we are to allocate blame (natural human behaviour), then we should consider blaming ourselves as part of the overall system that, when it fails, can lead to this type of accident.
Probably all of us have transgressed one or more of the landing parameters without problems, but how many realised how close the landing was to becoming a serious incident of even an accident.
1. Statistically we land fast (just check the FDM data); we tend to land long, or accept long landings in proportion to the length of the runway (SEMSA data).
2. We land on wet runways, but how wet is wet? The small difference between 2.5 mm and 3.1 mm of water is probably not detectable during operations, but increasing water depth has a significant effect on braking effectiveness? When does wet become contaminated – ‘wet with water patches ?’ – I have never heard a 'wet contaminated' report broadcast.
3. We have the perception that a grooved runway surface is more effective (JAR-OPS tells us so), but how do we know if the grooves are clear or blocked with rubber etc? Do we really understand the differences in friction between a good porous black top and the often quite low friction on concrete runways? Do we know how well drained the runway is, and even with good drainage it takes time to be effective which could be degraded in crosswinds (damming effect).
4. We often land in tailwinds, but do we actually know what change of wind occurs after the last wind check – and was the last ‘wind’ given on short final or 5 mins ago from ATIS.
5. Do we always know the actual touchdown speed, and where was the point of touchdown with respect to the optimum?
6. We land with Cbs in the vicinity of airports, but how many checks are made on short final to determine storm movement and current position? We may consider the threat of windshear when in the air and carry additional speed, but do we consider loosing that energy before or during landing; and what if the windshear hits when you are on the ground?
I suggest that few pilots actual know what all of the conditions are during a landing, thus it is futile to ask why didn’t a crew do that – because it is most probable that they did not know - no one else knew, no one told them, or the crew/others failed to observe or understand the relevance of the information they had.
Very few pilots actually know what safety margins remain during normal landings; those that do, should have some red annotated experiences in their flying logbook. (i.e. wet landing at LCY in a crosswind at night).
In many cases our lack of basic knowledge about aircraft performance fails to set an appropriate safety line. This can be degraded further by examples of poor operating practices from both our peers and our own behaviour, and a wide range of other human factors.
One of the human problems is that we tend to reset our safety line to the last ‘successful’ landing. Few of us conduct a self-debrief to consider what the actual margin of safety was, and ask ‘what would happen if’ any other parameter approached the limit and what would the consequences be. A debrief, self and with crew, is a powerful means of readjusting positively or reconfirming our personal safety limits on which the industry depends on.
Do we really consider any of the individual transgressions as a threat to safety? What happens if there were simultaneous transgressions - wet runway and tailwind; then what margin is there for error - incorrect wind, misread friction level, incorrect airspeed, long landing, windshear?
If you want blame, then we should blame ourselves.
However, we are able to change how we operate as individuals and we can influence others with positive examples, and if we see an uncontrolled threat then we can report it e.g. slick surface, large quantities of paint / rubber / de-icing fluid on the runway.
For those other, rare circumstances, then we have to respect the weather and be aware of our and others fallibility. With two or more transgressions (amber alerts) do we promote the threat to a red warning level and follow TEM rule 1:- Avoid the threats.
We can and must improve knowledge and thus our own professionalism throughout our career. This is not the forum for the unprofessional or the “I can do’ers”, but for those who wish to learn then let us have an open and educating exchange of information.
Errors in aviation decision making.
How good pilots make bad decisions.
Managing threats
--------------------
Unless specifically authorized everything else is forbidden.
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Follow link to watch AF video showing the cabin evacuation simulator.
cabin evacuation
BTW, the captain is back to France but still in a hospital.
cabin evacuation
BTW, the captain is back to France but still in a hospital.
Last edited by hart744; 11th Aug 2005 at 21:37.
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To: alf5071h
Question . . . sort of what I asked earlier . . . with no replies.
If, due to technical peculiarities of the guidance equipment, you arrived at visual to threshold and your TCH was going to be ~ 150' instead of the published 58', and given the conditions . . . what is the prudent course of action?
RESA
Question . . . sort of what I asked earlier . . . with no replies.
If, due to technical peculiarities of the guidance equipment, you arrived at visual to threshold and your TCH was going to be ~ 150' instead of the published 58', and given the conditions . . . what is the prudent course of action?
RESA
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RESA, of all the Ops manuals I've seen, if unstable below 500', then it's a mandatory go around. Unstable means "not in the slot" (a whole lot of parameters, but that's what it means) .
150' over the THR will have you touching down 3000' down the runway. It seems that they may have been higher than 150 if they hit mother earth 4000' down the strip and that is definitely not in the slot.
Rather be flying, I hear what you say, and understand, but if the TS was so close that it precluded a go around, then perhaps the approach should never have been made, and that's [particularly relevant if a turn in away from the TS was not feasible during the MA path. This was an experienced crew, and even a relatively inexperienced crew would have looked at that. See bit on heightened awareness below.
Once again, I've seen manuals that state an aircraft must not approach within5kms-5nm from approaching TS, even further behind receding TS, and that would not prevent a successful go around. The extra couple of thousand feet eaten up in the float was valuable distance that could have been used in the GA.
I think most pilots are the same; when things start to unwind, we move into a level of heightened awareness, and this is one of those situations, surely. It's easy to sit back and relax on a CAVOK day,but with terminal area TS, possible microburst, tailwind landing, wet runway, etc the bells start ringing.
Pilots have enormous authority, but within narrow parameters; does it fit within the box? If not, don't do it and you ll be safe. It's the rules that make it safe.
alf, nice post with good info.
Tripper, you are wrong. Most pilots don't think that they cant make a mistake, but they HOPE they don't make a mistake, and particularly one of these proportions. You're not airline management are you?
150' over the THR will have you touching down 3000' down the runway. It seems that they may have been higher than 150 if they hit mother earth 4000' down the strip and that is definitely not in the slot.
Rather be flying, I hear what you say, and understand, but if the TS was so close that it precluded a go around, then perhaps the approach should never have been made, and that's [particularly relevant if a turn in away from the TS was not feasible during the MA path. This was an experienced crew, and even a relatively inexperienced crew would have looked at that. See bit on heightened awareness below.
Once again, I've seen manuals that state an aircraft must not approach within5kms-5nm from approaching TS, even further behind receding TS, and that would not prevent a successful go around. The extra couple of thousand feet eaten up in the float was valuable distance that could have been used in the GA.
I think most pilots are the same; when things start to unwind, we move into a level of heightened awareness, and this is one of those situations, surely. It's easy to sit back and relax on a CAVOK day,but with terminal area TS, possible microburst, tailwind landing, wet runway, etc the bells start ringing.
Pilots have enormous authority, but within narrow parameters; does it fit within the box? If not, don't do it and you ll be safe. It's the rules that make it safe.
alf, nice post with good info.
Tripper, you are wrong. Most pilots don't think that they cant make a mistake, but they HOPE they don't make a mistake, and particularly one of these proportions. You're not airline management are you?
Last edited by relax737; 12th Aug 2005 at 05:23.
TCH 50 - 100' According to FDR
This was disclosed at the Aug. 9 TSB press conference.
TSB also announced that they would be trying to determine a more precise number, but that 50-100' is the best they were able to determine for TCH at the time.
[Speculation follows]
I can imagine that the approach end was largely VFR with a line of nasty CBs running north-south at what seemed far enough west of the airport at the FAF -- and too close at the threshold.
Back at the FAF the view may have looked within acceptable parameters for a landing and the missed approach path may not have been assessed against the location of the CBs.
I suspect your average CB at that location would likely have allowed a normal landing. This one did not. So how do you tell the difference in time to decide properly?
TSB also announced that they would be trying to determine a more precise number, but that 50-100' is the best they were able to determine for TCH at the time.
[Speculation follows]
I can imagine that the approach end was largely VFR with a line of nasty CBs running north-south at what seemed far enough west of the airport at the FAF -- and too
close at the threshold.Back at the FAF the view may have looked within acceptable parameters for a landing and the missed approach path may not have been assessed against the location of the CBs.
I suspect your average CB at that location would likely have allowed a normal landing. This one did not. So how do you tell the difference in time to decide properly?
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In addition the KLM crew and all the other crews sitting in approach trail behind AF had decided it was safe to make an approach/missed approach.
Indeed what missed approach did the KLM aircraft follow when they went around.
Its never nice being the first little guinea-pig to test the water, so to speak, after a period of protracted holding in bad weather.
Indeed what missed approach did the KLM aircraft follow when they went around.
Its never nice being the first little guinea-pig to test the water, so to speak, after a period of protracted holding in bad weather.
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Don't think the KLM even made an approach, and certainly no go-around. He was in sequence (exactly where not revealed) when ATC advised YYZ closed due to the crash, so KLM immediately issued 'Pan' and diverted to SYR.
Reported that ATC offered YHM (Hamilton) which didn't make a lot of sense given that the worst WX was between YYZ and YHM, unless a wide arc over the lake was flown.
Reported that ATC offered YHM (Hamilton) which didn't make a lot of sense given that the worst WX was between YYZ and YHM, unless a wide arc over the lake was flown.
RESA
Re your question “If, … you arrived at visual to threshold and your TCH was going to be ~ 150' instead of the published 58', and given the conditions . . . what is the prudent course of action?”
The ‘stock’ safety answer is – go around. However, I suspect that there may be a few doubters and many more “what if’ers”. If so, these views could represent some of the human factors issues that relate to the circumstances, situation awareness, decision making, and importantly the risk assessment of options for action – land or go around.
In this instance I would argue that good background knowledge of the certification rules (and assumptions) would improve the choice of action.
First, continuing to land will involve risk; the key judgment is how much. The certification margins for landing distance contain a small allowance for error; or in UK CAA English “variation in the values of various parameters from those assumed at certification”. Good guidance on these matters is in AIC 11(P164)/98 ‘Landing performance of large transport aeroplanes’ (free download, but registration and cookies enabled required, then go to Publications, UKAIC , Pink safety related). Also see AIC 61(P195)/99 ‘Risks and factors associated with operations on runways affected by snow, slush or water’ Note the statement ‘For JAR-OPS performance purposes, runways reported as WATER PATCHES (25% cover) or FLOODED should be considered as CONTAMINATED’.
Thus with ‘all other things being equal’, a landing from a gross error of 100 ft high (150 ft @ threshold) the landing distance could be extended by 2000 ft (AIC11/98). Probably at most airports with long runways this increase would be accommodated and the crew would write-off their error against ‘normal exercising of judgement’ (shrug of shoulder) with increased braking / full reverse. However, if any other physical condition that affects a landing is ‘at variance with the assumptions’ then there could be no margin for any operating error or misjudgement. It is often the case that the misjudgement of the less obvious variables cause the greatest problems (different wind speed / direction from that used in the planned performance, runway surface (baseline mu), runway condition / depth of water). Then there is human skill; in the limiting conditions in the above scenario a landing would require a firm touchdown, prompt selection of spoilers / reverse, and use of MAX brake – at least until assured of stopping (another judgment).
The alternative option of executing a go around at any time during the approach or even from the point of touchdown should involve far less risk.
This might be refuted by some Canadian operators due to the advice given in the poorly worded AC 0141 (13 May 1998), which implies that aircraft ‘may not be able to’ (my words) conduct the manoeuvre from a ‘low energy state’; whereas a better explanation might have been to add ‘without increased risk’ (which can be combated by appropriate crew skills). However the AC does correctly conclude “ … operators should review their operations to ensure that pilots and training personnel are adequately aware of the hazards inherent in and procedures for dealing with low-energy operations”, i.e. late go-arounds.
The fundamental basis of aviation is that all aircraft are safe to operate within the constraints of the flight manual and when flown as per the manufacturer’s operating instructions. Flying a go-around is safe; we must put aside any concerns of conducting an infrequently practiced maneuver, unfounded fears of lack of control, or inadequate performance, the next failure, etc; the flight deck is not the place for these negative personal attitudes that can bias situation awareness, judgment, and decision making.
From the environmental aspect, a go-around into a Cb is not a good option, but if essential, it is still safe; the aircraft will not breakup or be thrown into the ground by a downburst, provided the appropriate action is taken. Normally a Cb hazard is identified and avoided well before starting the approach this requires crews to consider the threat for the approach and landing, and the go–around route.
I would argue that the above supports the ‘stock’ safety answer – go around, it is the lower risk option. To reinforce this we must bias our judgment towards a go around (go around minded) on every approach. Our mind set should consider the definition of a ‘landing’ as “an approach without a go around”.
We have to dispel the subconscious pressures that come from of the routine objective of always landing, the background commercial pressures, peer pressure (fellow pilot or ATC) - ‘the stigma’ of a go around, and the natural human desire to help others – land on time, don’t divert, don’t foul up the traffic pattern, give the pax a smooth ride. We have to focus on the safety aspects of the flying task.
A decision to transition to a landing in marginal conditions constrains the aircraft to a short narrow strip of land without any flexibility in altitude, heading, distance or time; whereas a go-around leaves open reasonable options of heading, altitude, speed, and within fuel constraints distance, time and location, – many more options than for landing. The action or consideration of a go-around may involve more workload or personal delay and disruption, but that’s what we are paid for – too ensure the safe conclusion to the flight.
In reality, if you have decided to start an approach and there is someone ahead, the airfield is ‘open’ and you are visual with both the runway and the weather, and you have done something similar several times before, then it takes very strong willpower to overcome the human fallibility for error … ‘Press-on-itis’. For the aircraft to end up high at the threshold implies that something preceded it, a tailwind shift or gust that is not noticed. The PF may see this as a flight error that s/he attempts to correct, the crew are now suckered in and with the additional attention on the flying task, all of the good thoughts and safety considerations that where planned beforehand are put in the background and the crew continues the landing, after that it’s history.
I suggest that personal flight safety based around good technical knowledge is one way of combating the subconscious biases; there are many others, but if, ‘on that day at that time’ all the weaknesses in the defences come into line then not even the luck that we all use on a daily basis will save us.
Good planning, go-around mindedness, early decisions, zero tolerance to violation of SOPs (stabilised approach limits), and resisting peer pressure will help. But ‘on that day at that time’ it is only you against the aircraft and the elements.
I suspect that the investigation into the accident in Toronto will find that some of the above issues are contributory to the cause, if so I hope that they will be discussed and solutions considered rather than leave them, as many reports do, as just human factors / human error.
--------------------
Unless specifically authorized everything else is forbidden.
Re your question “If, … you arrived at visual to threshold and your TCH was going to be ~ 150' instead of the published 58', and given the conditions . . . what is the prudent course of action?”
The ‘stock’ safety answer is – go around. However, I suspect that there may be a few doubters and many more “what if’ers”. If so, these views could represent some of the human factors issues that relate to the circumstances, situation awareness, decision making, and importantly the risk assessment of options for action – land or go around.
In this instance I would argue that good background knowledge of the certification rules (and assumptions) would improve the choice of action.
First, continuing to land will involve risk; the key judgment is how much. The certification margins for landing distance contain a small allowance for error; or in UK CAA English “variation in the values of various parameters from those assumed at certification”. Good guidance on these matters is in AIC 11(P164)/98 ‘Landing performance of large transport aeroplanes’ (free download, but registration and cookies enabled required, then go to Publications, UKAIC , Pink safety related). Also see AIC 61(P195)/99 ‘Risks and factors associated with operations on runways affected by snow, slush or water’ Note the statement ‘For JAR-OPS performance purposes, runways reported as WATER PATCHES (25% cover) or FLOODED should be considered as CONTAMINATED’.
Thus with ‘all other things being equal’, a landing from a gross error of 100 ft high (150 ft @ threshold) the landing distance could be extended by 2000 ft (AIC11/98). Probably at most airports with long runways this increase would be accommodated and the crew would write-off their error against ‘normal exercising of judgement’ (shrug of shoulder) with increased braking / full reverse. However, if any other physical condition that affects a landing is ‘at variance with the assumptions’ then there could be no margin for any operating error or misjudgement. It is often the case that the misjudgement of the less obvious variables cause the greatest problems (different wind speed / direction from that used in the planned performance, runway surface (baseline mu), runway condition / depth of water). Then there is human skill; in the limiting conditions in the above scenario a landing would require a firm touchdown, prompt selection of spoilers / reverse, and use of MAX brake – at least until assured of stopping (another judgment).
The alternative option of executing a go around at any time during the approach or even from the point of touchdown should involve far less risk.
This might be refuted by some Canadian operators due to the advice given in the poorly worded AC 0141 (13 May 1998), which implies that aircraft ‘may not be able to’ (my words) conduct the manoeuvre from a ‘low energy state’; whereas a better explanation might have been to add ‘without increased risk’ (which can be combated by appropriate crew skills). However the AC does correctly conclude “ … operators should review their operations to ensure that pilots and training personnel are adequately aware of the hazards inherent in and procedures for dealing with low-energy operations”, i.e. late go-arounds.
The fundamental basis of aviation is that all aircraft are safe to operate within the constraints of the flight manual and when flown as per the manufacturer’s operating instructions. Flying a go-around is safe; we must put aside any concerns of conducting an infrequently practiced maneuver, unfounded fears of lack of control, or inadequate performance, the next failure, etc; the flight deck is not the place for these negative personal attitudes that can bias situation awareness, judgment, and decision making.
From the environmental aspect, a go-around into a Cb is not a good option, but if essential, it is still safe; the aircraft will not breakup or be thrown into the ground by a downburst, provided the appropriate action is taken. Normally a Cb hazard is identified and avoided well before starting the approach this requires crews to consider the threat for the approach and landing, and the go–around route.
I would argue that the above supports the ‘stock’ safety answer – go around, it is the lower risk option. To reinforce this we must bias our judgment towards a go around (go around minded) on every approach. Our mind set should consider the definition of a ‘landing’ as “an approach without a go around”.
We have to dispel the subconscious pressures that come from of the routine objective of always landing, the background commercial pressures, peer pressure (fellow pilot or ATC) - ‘the stigma’ of a go around, and the natural human desire to help others – land on time, don’t divert, don’t foul up the traffic pattern, give the pax a smooth ride. We have to focus on the safety aspects of the flying task.
A decision to transition to a landing in marginal conditions constrains the aircraft to a short narrow strip of land without any flexibility in altitude, heading, distance or time; whereas a go-around leaves open reasonable options of heading, altitude, speed, and within fuel constraints distance, time and location, – many more options than for landing. The action or consideration of a go-around may involve more workload or personal delay and disruption, but that’s what we are paid for – too ensure the safe conclusion to the flight.
In reality, if you have decided to start an approach and there is someone ahead, the airfield is ‘open’ and you are visual with both the runway and the weather, and you have done something similar several times before, then it takes very strong willpower to overcome the human fallibility for error … ‘Press-on-itis’. For the aircraft to end up high at the threshold implies that something preceded it, a tailwind shift or gust that is not noticed. The PF may see this as a flight error that s/he attempts to correct, the crew are now suckered in and with the additional attention on the flying task, all of the good thoughts and safety considerations that where planned beforehand are put in the background and the crew continues the landing, after that it’s history.
I suggest that personal flight safety based around good technical knowledge is one way of combating the subconscious biases; there are many others, but if, ‘on that day at that time’ all the weaknesses in the defences come into line then not even the luck that we all use on a daily basis will save us.
Good planning, go-around mindedness, early decisions, zero tolerance to violation of SOPs (stabilised approach limits), and resisting peer pressure will help. But ‘on that day at that time’ it is only you against the aircraft and the elements.
I suspect that the investigation into the accident in Toronto will find that some of the above issues are contributory to the cause, if so I hope that they will be discussed and solutions considered rather than leave them, as many reports do, as just human factors / human error.
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Last edited by alf5071h; 23rd Aug 2005 at 18:29.
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alf5071h
Thanks much for the reply!
I am always interested, being on the "earth bound" side of the "Aids", in knowing what is going through the head of the "client". Technical equipment always has some little quirks and we don't like to think we left some traps out there to trick ("suckered in") anybody.
I have been amazed, over the years, how some push the limits well beyond the published capabilities of certain equipment . . .”It’s published as a CAT I, why did you do a coupled CAT III landing . . . got away with it before, let's try it again"?
Anyway . . . thanks again
RESA
Thanks much for the reply!
I am always interested, being on the "earth bound" side of the "Aids", in knowing what is going through the head of the "client". Technical equipment always has some little quirks and we don't like to think we left some traps out there to trick ("suckered in") anybody.
I have been amazed, over the years, how some push the limits well beyond the published capabilities of certain equipment . . .”It’s published as a CAT I, why did you do a coupled CAT III landing . . . got away with it before, let's try it again"?
Anyway . . . thanks again
RESA
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RESA
Quote:”It’s published as a CAT I, why did you do a coupled CAT III landing . . . got away with it before, let's try it again"?
I don’t think that you fully understand what we do. The airplane doesn’t know a CAT I from a CAT III, furthermore pilots wouldn’t even plan an approach using CAT III critique on a Cat I approach. That would be sort of irresponsible don’t you think?
There are a few supposedly certified CAT III approaches in the world that I wouldn’t do a real CAT II on let alone a real CAT III due to the poor maintenance of the facility. It’s obvious to me that you’ve never experienced a real CAT III or understand the planning that goes into one; otherwise you would never make such a foolish statement.
Quote:”It’s published as a CAT I, why did you do a coupled CAT III landing . . . got away with it before, let's try it again"?
I don’t think that you fully understand what we do. The airplane doesn’t know a CAT I from a CAT III, furthermore pilots wouldn’t even plan an approach using CAT III critique on a Cat I approach. That would be sort of irresponsible don’t you think?
There are a few supposedly certified CAT III approaches in the world that I wouldn’t do a real CAT II on let alone a real CAT III due to the poor maintenance of the facility. It’s obvious to me that you’ve never experienced a real CAT III or understand the planning that goes into one; otherwise you would never make such a foolish statement.
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alf5071h when evidence of a (very) long t/d for AF658 became clear, I started to suspect some "press-on-itis" at work. The cell(s) to the W. might have been one factor, but has their fuel status been established (I may have missed it) ?
I believe the CVR contains earlier discussion of diverting to YOW - which they eschewed - so is it possible the prospect of a go around to another hold or else reneging on the decision not to divert might have trapped them into a got to make this one work mindset ?
I've been there
I believe the CVR contains earlier discussion of diverting to YOW - which they eschewed - so is it possible the prospect of a go around to another hold or else reneging on the decision not to divert might have trapped them into a got to make this one work mindset ?
I've been there
As you say this is all speculation since we dont know the remaining fuel but (and I know I am sticking my neck out here) perhaps, from a strictly decision making point of view, there might be some similarities between this accident and the BY one at GRO where the aicraft exited the side of the runway after an unusual arrival following an approach in not dissimilar weather.
Concerning CAT !/III surely from a pure systems point of view there is no reason why the aircraft could not have done an autoland (yes I know there are crosswind limits, weather limits etc) but if you really running low on fuel it might be better to autoland.
Pith helmet suitably donned!
Concerning CAT !/III surely from a pure systems point of view there is no reason why the aircraft could not have done an autoland (yes I know there are crosswind limits, weather limits etc) but if you really running low on fuel it might be better to autoland.
Pith helmet suitably donned!