How this Rare phenomenon almost STALLED an Airbus A318! 😨 | Air France flight 7512

an airbus a318 is in a 30 degree pitch shop attitude within inches of a low altitude stall in landing configuration what's broader there is partly the actions and inactions by the crew but also a little known feature of the instrument landing system do you have an idea what that feature might be stay tuned a huge thank you to nordvpn for sponsoring this video this serious incident that i'm about to talk about in this video took place on the 20th of december 2019. it involved an air france airbus a318 with 114 passengers on board three cabin crew members and two pilots and it happened about 9 16 utc in the morning before i tell you about what happened on this day i just want to give you some background information on the arrival airport toulon which is in southern france tillon airport is a mixed military civilian airport that is a couple of kilometers east of tillon city and about 40 kilometers east of marseille the area is beautiful lovely beaches quite a lot of mountains around it kind of reaches in towards the mediterranean sea even though it's beautiful it is a very tricky airport to fly into it has across runway the main runway is from the 0523 that one is about 2123 meters long but if you land off the only instrument landing system ils approach they have with 05 it's only about 1904 meters because of a displaced threshold so it's on the short side if you need to land on runway 2 3 well then you have to do a quite complicated visual maneuver which requires quite good weather in order to do it and if you want to land on the cross runway the only runway that a civilian airliner can land on at least when i was there last is runway 3-1 and you have to do a ils approach and program with 0-5 and then you have to break off that ils approach and do a non-reciprocal circling approach in for runway 3-1 so there's no actual approach procedure into that runway that's largely because of a lot of mountains just north of the airport because it is in a very beautiful area there's loads of general aviation aircraft flying around they're all speaking in french so if you're speaking english it's hard to understand what they're saying and you also have lots of helicopter and military traffic so when you're flying into lawn you have to be really careful right it takes a lot of briefing and you have to really be on your top game as you're flying in there on the day of the incident the crew received the weather prior to them starting to descend and they realized that the weather in toulon was not great okay it had a broken cloud layer of about 1700 feet there was a visibility of 5 000 meters in light rain and mist and the surface wind was 150 degrees at 12 knots gusting 19 and it had been gusts recorded up to 40 knots during that day so that means that that wind is more or less crosswind but it also has a little bit of tailwind in front of a city five now the crew started looking at this and they realized that the weather was going to be marginal for the visual approach maneuver internal 2-3 so they would have to consider a tailwind landing on cyr5 instead they did the performance for that they realized that even with the worst wind they were still able to land their airbus 318 in these conditions so they opted to go for the strategy and ils approach with tailwind for runway 05 at this point i also want to explain a little bit how the instrument landing system works because it's going to become really important for this story so the ils system is divided into two different parts you have the localizer which shows the crew how to fly horizontally as in from left to right and you have the glide slope which shows how to fly vertically up and down the way that the glide slope does this is that it has a array of antennas that's situated just a beam the poppies normally at the center of the touchdown zone and those antennas are directional antennas and they send out a lobe each one lobe is of 90 hertz that's the upper lobe and one lobe is 150 hertz which is the lower lobe these lobes are centered in a way so that when they intersect and there is a perfect mix of 90 hertz which is 150 hertz you have the three degrees glide in the aircraft on the other hand there is an ils receiver that gets these signals and interprets them and if this receiver feels that there's a little bit more 90 hertz being received well then it knows that the aircraft is above the glide slope if it feels that it's a little bit more 150 hertz it knows it's below and if it's just right it means that it's on the glide slope and it sends that signal to the pilots and we get an indication on our primary flight display or our ils instrument that shows a little glide slope dot that is either above or then it travels down towards the middle which is where it's supposed to be or it goes below which indicate that we are above the glide slope this instrument is very accurate but it's not very smart it only interprets the signals it's receiving and sends it on to the pilots it doesn't give any more information of whether or not it makes any sense and that's going to become really important in this story the pilots have received the weather they've realized that it's marginal and they've opted to go for runway 05 with a bit of a tailwind but when they discuss the tailwind as a threat they only discuss it in the kind of confines of landing distance required they don't really discuss how that tailwind might affect them during the approach phase the first officer is the pilot flying for the flight he has about 5500 hours about 400 hours on the airbus 320 family the captain who's pilot monitoring has more than 10 000 hours but the large majority of his time is flown on the boeing triple seven on long-haul flights and he's just moved over back to the airbus 320 family earlier in 2019 anyway they initiate the descent and they do so on time there's no delay to it but as they're descending in to watch to loan now which by the way it's the first time that both the first officer and the captain is flying into toulon the first officer starts realizing that he is ending up a little bit high on profile there are many reasons that that might happen sometimes our traffic control keeps us high because of crossing traffic below us and sometimes we get shortcuts that gives us less track month in order to descend the first officer recognizes this he uses the speed brake to try to get back onto profile but he keeps staying a bit above the normal profile as they get closer toward toulon they get not five available this point the crew is also clear to descend to 1900 feet and remember that altitude it's going to become important when the crew turns in towards palmer the aircraft is very high and also as they're turning in they start to encounter a very strong tailwind in the order of about 50 knots straight from behind them 50 knot sail wind is a very strong tailwind and it can cause a lot of problems for commercial aircraft because as we are getting down and getting closer towards our ils approach we need to both get down onto our glide slope that means reducing our potential energy but we also need to slow down to reduce our kinetic energy and the problem is that there's only so much slowing down that you can do all right and tailwind will actually add to our kinetic energy and this is what's happening to this aircraft right now as they're turning in towards the palmer point they're at about 16 miles away from the runway their altitude is 6500 feet at this point and they have an indicated airspeed of 250 knots but the ground speed which is the speed they're actually moving over the ground is over 300 knots and that's because of that really strong tail wind now to put that in perspective when i fly the 737 800 we use an easy kind of calculation in order to see whether or not we're high on profile and the way that we do that is that we take the altitude we have over the runway elevation we multiply that by three and then we add one nautical mile for each ten knots that we need to decelerate down to 200 knots where we can start taking the flaps so in this case this crew is at 6500 feet you take that time to three that's about 19 and a half right and then you take 300 knots down to 200 that's another 10 miles so that gives you about 29 miles but they're 16 miles so that would show you that they are very high now there might be some variations because the airbus 318 is not the same as the boeing 77800 but they're in the same ballpark talon tower has previously when they first got into contact with the pilot asked them what approach they want and told them that the weather is a little bit marginal from with 2-3 so the crew has already told them that they want to try for the ils runway 05 and air traffic control has agreed to this but now something really interesting happened as the crew passes the palmer point air traffic control comes back in and asks them if they would like to do a holding pattern to lose some altitude whenever you hear air traffic control ask you something like that unless there is traffic reasons for you to hold you should really take a step back and look at what your situation is like because the only reason that traffic control will suggest something like that is because they're looking at their radar screen and they're realizing that you are very high or very fast but in this case the captain looks over towards the first officer who's pilot flying the first officer gives him a nod saying that it's okay and the crew elects to continue to go straight in for the eyelash instead of taking up the hold in later interviews the crews were asked why they chose to do it like this and the captain who was pilot monitoring he basically said that well he looked at the first officer the first officer was happy with the situation and he didn't do any recalculation of the energy state of his aircraft the first officer on the other hand he thought yeah i'm a little bit high here but i can continue this approach down to about 1500 feet or minimum 1000 feet if i'm not stabilized then i'm just going to go around and i'm going to come back in for a second approach in a better energy state and that's a pretty reasonable way of thinking the next thing that happens is that the crew captures the localizer that's the horizontal part of the eyeless approach the one that shows you how to turn left or right and when they capture the localizer they select flaps one they select the gear down they also select approach mode and this is very important now with gear down flaps one the speed brakes still extended they started to descend quite fast and they're starting to get closer to the glide slope at this point they also engage the second autopilot which i've been told by other airbus crews that it's very common that airbus crews do in order to keep commonality between both category 3 outer land approaches and normal category 1 approaches on boeing we don't do that we only do that when the aircraft is about to do an outer land the aircraft is now descending down towards the glide slope but they're still far above it the ils instrument inside of the cockpit is showing full deflection fly down and remember how they had 1900 feet set as their cleared altitude this is important because as you're descending down and you're capturing the glide slope well then the autopilot will disregard any altitude that you set in the altitude window it will just follow the glide slope and the only time that you will use that altitude window is going to be for your missed approach altitude but if you never capture the glide slope well then the autopilot will assume that whatever you have set in your altitude window is where you want to level off and this is exactly what's about to happen to this aircraft so at time 09 1507 at 2200 feet the fma switches over to altitude star and the aircraft pitches up and prepares to level off at 1900 feet none of the pilots notices this fma change nor the fact that the aircraft is pitching up they are probably too focused on the configuration of the aircraft and reading the landing checklist at this point but but i find that very very strange because if you are the pilot flying and you know that you're above the glide slope you will be fully concentrating on trying to increase your drag and get that light slope capture because you know that there is a possibility of this happening in fact there is even a standard operating procedure in air france at the time of this incident where if you are capturing a glide slope from above you need to set the altitude to an altitude above the aircraft level that way you'll be able to use vertical speed in order to get down capture the glide slope without the aircraft leveling off but in this case the aircraft is now level flight at 1900 feet for every second that goes by they become higher and higher and this is also where we have to start discussing another feature of the instrument landing system remember how i told you that the glide slope functions by sending out two lobes to radio signals with different frequencies one at 150 hertz and below and then 90 hertz above well the problem with any directed antenna is that no matter how well built they are they will always also transmit something called secondary lobes these are weaker radio signals with the same frequency that happens at set intervals in the case of the glide slope we have the primary lobe sitting at about three degrees glide slope but then you'll have a secondary glide slope that's happening at nine degrees and another one at 12 degrees now the issue with these false glide slopes is that not only are they much steeper than the 3 degrees glide but also in the case of the 9 degree false glide they are reversed that means that you will hit the 90 hertz lobe first and then the 150 low and remember how i told you that the ils instrumentation in board the aircraft is not very smart it only kind of interprets the signals it gets and send it on to the pilots and also the autopilot well that is going to become really important right now because as the aircraft is now sitting for about 20 seconds in level flight getting further further away from three degrees glide it's also getting closer and closer to this false glide slope the way that the pilots could have noticed this if they would have looked at their ils instruments would have been that even though they were level flight at 1900 feet now going further and further away from their proper glide slope all of a sudden the glideslope indicator became alive and started rising up towards the center when it reached the center then since the approach mode was armed the glide slope now captured but as the aircraft flew through the center of these signals it now came above this secondary glide slope but remember the signals are reversed so instead of indicating a fly down signal the ils instrument now showed a violent pitch up instead within the next 10 seconds the aircraft pitches up to 30 degrees pitch up and remember this is in landing configuration which means the landing gear is hanging out and also the landing flaps that's an enormous amount of drag the outer throttle tries to add thrust but it's impossible the speed starts falling off and with the combination of the speed decreasing and the pitch being that high the angle of attack is also increasing this is followed by a speed speed warning as the aircraft goes into alpha protection mode and then into alpha floor mode these are two protection modes that the airbus had in order to make sure that aircraft is not going to stall at the same time air traffic control calls the pilots and tells them to go around but they don't get a response back the first officer looks down onto his fma and realizes that it says toga lock there now token lock is a feature of the alpha floor protection of the earbuds it's when the airbus feels that the angle of attack is closing in on stall it brings the outer thrust into toga and it locks it in together to make sure that maximum trust is being given to the pilots now the only way to disengage the toggle lock is to actually bring the thrust back to idle that disconnects the outer throttle and then bring it up into talk again and this is what the first officer does when he does so he doesn't tell the captain that he is going around also he realizes that the pitch of the aircraft is way too high and he starts pitching forward as part of the aircraft upset procedure now an upset can be defined as whenever the nose of the aircraft goes above 25 degrees pitch which it does in this case and what you need to do is you need to get the nose down and you need to get the speed back under control the aircraft reaches a speed of 96 knots that's 20 knots below the vls the velocity lowers selectable speed which is the minimum speed that is supposed to fly it's also just two knots over the 1g stall speed that's how close this aircraft came to actually stalling at 1900 feet the aircraft now starts climbing with about a thousand feet per minute and the first officer who initiated the recovery procedure by pitching down now stops his pitch down at about 15 degrees nose up this is what the flight directors is telling him to do which are now in something called an srs mode the problem with that is that 15 degrees nose up is still way too high of a pitch and the aircraft is still keeping the slow speed the aircraft is below its velocity lower selectable for 46 full seconds before they start to regain the speed they continue to climb up to 4000 feet which is the missed approach altitude they start retracting the flaps they take the gear up and once they're done with that they get vectors around in for another ils approach wrong with 05. so this was clearly a very serious incident and it raises a few really important questions like for example it was a serious incident but no one was hurt the aircraft wasn't damaged so how come we even know about this how come there is a final report for me to base this video on and also why isn't there a built-in system in the aircraft that stops it from capturing a false glide slope and pitching up to 30 degrees this and also what we can learn from this incident i will cover in just a few seconds after this short message from my sponsor this video is brought to you together with nordvpn now you know just as well as i do how important it is to protect you and your data in this day and age i use the nordvpn app whenever i'm out traveling so if i go into a cafe or an airport i want to use the public wi-fi well then i switch it on and it will tell me whether or not that network is actually safe and secure to use and if it's not i just don't use it it also helps me to encrypt my data and my position but probably what i use it the most for is to get past these pesky regional restrictions so if i'm out traveling somewhere and i want to watch my favorite netflix series well then by a click of a button i can be back in spain again which makes sure that all of the library in spain is available to me and you can use up to six different devices on one single deal so if you think peter that sounds great well in that case go to the video description below click the link which is nordvpn.com pilot and that will give you a whopping 73 of the two year deal plus an additional four months absolutely for free so go down click the link and start protecting yourself on the internet today this incident and other similar incident actually worked as a really good learning experience for the industry there have been a little bit of maybe misunderstandings or lack of knowledge about this false secondary glide slope and this really highlighted how important it is to monitor your flight path especially if you're coming in a little bit hot and high and you're lacking some track miles the causes of the incident was deemed to be the underestimation of the crew the threat that was posed by the significant tailwind during the approach that led them to intercept the glideslope from above also the poor monitoring by both the captain and the first officer of the energy state of the aircraft but also of the fma if they would have checked their fma and monitored what the aircraft was doing while they were configuring and reading the checklist well then they would have noticed that it had leveled off at 1900 feet and that they were going straight towards that secondary glide slope they also failed to take into consideration or properly use the suggestion from air traffic control to take one lap in the hold and this serves as a really good reminder for any pilot out there that if you come into a situation where you feel that you don't have enough track mods you feel a little bit hot and high you're not really comfortable with what's happening to your aircraft just ask for some extra track miles tell air traffic control to get some extra radar vectors if you're on radar or ask for a turn in the hold it might extend your flight time with a few minutes but it's most of the time much better than ending up in a situation like this or just having to do a go around and then coming in for a second approach the fund report also mentioned that it would have been helpful to have more defined gates at different distances and as a consequence of this and other similar incidents we now do much more training in the simulator about capturing light slope from above and avoiding these high energy approaches as a result from this investigation efron's also updated guidance to their crews on how to handle high energy approaches and how to capture glide slopes from above but that doesn't answer the question to why we know about this incident in the first place since there was no damage and no one was hurt the answer to that is simple this was reported by the airline or the crew and this brings me to maybe the most important point that i have with this video there's been so many comments on the previous videos that i've done about serious incidents where people out in the audience think these pilots shouldn't be flying they should be fired they should be punished i hope i'll never get to fly with one of these pilots again and that completely misses the point with these type of videos the only reason that we can do videos like this where you out there understand what's going on where pilots learn about this is just culture in the airline it means that pilots do not feel that they've run the risk of being fired if they report something that's happened to them even if it was their own fault i cannot overstress this right this is a fundamental principle for why the airline industry is so safe we report every single thing that we think have any type of safety bearing so that the airline can look into changing procedures so that we can change our training so that we can confirm better and safer every single day without having to learn from a serious accident the only thing that would ever lead to a pilot facing disciplinary procedures is gross misconduct it's when they voluntarily and knowingly goes against rules and regulations and standard operating procedures and that causes the aircraft to come into an unsafe state that or trying to hide something that they've done that can have serious consequences but as long as you're honest and you made a mistake and it's an honest mistake well then what's going to happen is that there's going to be an investigation if it's serious enough that's going to lead to a report like this that might lead to changes in standard operating procedures or some training for the involved crew so make sure that they have the knowledge and the skill to avoid that ever happening again and that's the way our safety management system and our just culture works and that's really important but what about the aircraft then how come that there's not a system on the airbus to stop it from capturing a false glideslope and doing these crazy pit shop maneuvers but it turns out that airbus actually does have a system like that it's just that at the time of this incident it had not yet been implemented on the older airbus types from the airbus 320 neo up to the airbus 350 and so on it was implemented and it is in the process of being implemented on all airbus types in this video i've talked about the alpha protection and the alpha floor systems and if you want to see a video where poor understanding of these systems actually led to an accident during an air show then check out the video up here if you want to support the channel consider becoming a part of my patreon crew or buy a t-shirt have an absolutely fantastic day and i'll see you next time bye

Channel: Mentour Pilot

Views: 695,585

Keywords: Air France flight 7512, false glideslope ils, false glide slope, false glide slope capture, Air crash, air crash investigation, air crash investigation 2021, air crash investigation national geographic, air crash investigation full episodes, air crash documentary, air crash video, aviation accidents explained, aviation accident clips crash animation, aviation incident reporting, aviation incident news, Mentour Pilot, mentour pilot crash, mentour pilot landing

Id: zcRN_UljROc

Length: 24min 58sec (1498 seconds)

Published: Sat Oct 23 2021