They Did WHAT?! Pilots CAUGHT in the Act!

0:00 Would you be okay with your pilots experimenting in the cockpit? Maybe trying out things they don't normally do or just checking how the aircraft systems really work? Well, it turns out that this does happen. And in this video, I will show you why that might not always be a great idea. Traffic. Traffic. Stay tuned. On the 28th of March 2017, an Air France crew was getting ready to operate their last flight of the day out of Paris Shel airport in Paris, France. The weather was generally clear with only some light winds, and the upcoming flight was going to take them over to Siri in Switzerland, where they would then finish their day with a nice night stop. The crew consisted of two pilots and

0:45 three cabin crew. And as the cabin crew was greeting the boarding passengers, the pilots started briefing for their takeoff and departure routting like they had done several times already that day. The captain was 51 years old and had been flying for Air France since 1999. He had accumulated 9,500 hours of total time and got his command on the Airbus A320 family back in 2008, which meant that he had now flown around 6,700 hours on it. His colleague, the first officer, was 36 years old and had been working with Air France since 2008, where he had started off directly on the Airbus A320. His total experience was around 5,500 hours, and almost all of it had therefore been flown on the same aircraft family, the Airbus A320. This

1:33 meant that both pilots were very experienced on the type and therefore also quite comfortable with it. But being comfortable doesn't always mean knowing everything as we will soon see. Now, another important detail in this story is that these two pilots had flown a lot with each other and they were very good friends. They had actually even told Air France's rostering department that they preferred flying together whenever possible. And since that was perfectly okay from the airlines point of view, the rosters had done what they could to accommodate this. Now I am mentioning this because of a quite interesting CRM aspect of friendship relationships in the cockpit. You see being very familiar with someone has both positive and negative consequences when it comes to a hierarchic

2:18 environment. It can be super positive because the pilots will know each other and know how they will react to various situations very intimately. And on top of that, it's likely that the operational part of the work will run super smoothly just because the pilots enjoy each other's company and will do everything they can to facilitate a good day. But the flip side is a filing down of the authority gradient, which is required in a cockpit, especially when things start to go wrong. You have probably all encountered this yourselves, being in a situation with a friend where you know that they're doing something slightly wrong, but you don't really want to speak up because it would ruin the mood and potentially affect the friendship. So, in a situation where you are the manager or the captain in this

3:03 case, being close friends with the subordinate can lead to some quite awkward situations. Now, having said that, I have absolutely loved flying together with almost all of my colleagues. And especially when you operate from a smaller base, you might often end up flying with the same person over and over again. And you know, you just need to make that work. But being aware of a kind of social complacency is also therefore really, really important. In any case, by the time that these pilots were finishing up their cockpit preparation, the time had passed 2100 local time, which meant that it was now fully dark outside. The last performance figures were eventually delivered, indicating that there would only be 35 passengers on board, and that meant that

3:50 their Airbus A318 would be very light. Now, even though that might sound like a good thing from a performance perspective, it actually also comes with a few complications. First of all, these aircraft are constructed to be flown with a weight corresponding to an almost full passenger load. And this means that an almost empty aircraft will feel a bit more twitchy and susceptible to turbulence etc. The takeoff speeds will also be lower and the combination of that and less general inertia will also make it easier to get into pilot induced oscillations where the pilot inputs are bigger than they need to be and therefore causes unnecessary rocking and perceived turbulence. Now that's definitely true on the boring 737 that I fly, but likely

4:36 less so on the Airbus, which has advanced flybywire controls that should be able to sense and handle those kind of things. But one thing that is definitely the same on both the Airbus and the Boeing is the effect of excess engine thrusts that a lighter aircraft will be subjected to. You see, obviously the engines are sighted to be able to generate enough thrust to easily accelerate the aircraft for takeoff even with maximum takeoff weight. And that means that there will be far too much takeoff thrust available if the aircraft is almost empty. So why would that be a problem? Isn't extra thrust a good thing? Well, again, it is and it isn't. From a pure performance point of view, it definitely can be in terms of takeoff

5:21 distance, climb performance, etc. But handling wise, not so much. And that's because normally an aircraft in this category will be aiming to climb with a speed of around V2, which is the safe engine out climb speed, or V2 + 10 if both engines are working. Those speeds will give the aircraft a good combination of climb performance and a low noise footprint and is therefore also what the flight directors on the pilot's primary flight displays will be showing them. Under normal circumstances, the thrust to weight ratio of the aircraft would result in a pitch up attitude of around 15 to 18° after takeoff, which will give approximately those speeds. And that's therefore also what the pilots are used to pitch for. But if the thrust stays the same and the weight is significantly

6:08 lower, well then the pitch will also need to be higher in order to achieve that same speed and the aircraft will therefore also climb significantly faster. But at the same time, pilots try to avoid pitch attitudes above 20° under normal circumstances, which in these cases could therefore mean pitching less than needed in order to keep that speed that I just mentioned and then just let the speed accelerate instead. On the Airbus, the engineers who programmed the flight directors had actually taken this into account, which meant that the flight director would not direct to a higher required pitch than 18° and instead just let the speed accelerate. The V2 + 10 not target is a minimum anyway and as long as the maximum speed for the flaps is not

6:54 exceeded, it doesn't actually matter if the aircraft accelerates a bit, but it will look quite unusual for the crew. In any case, this was rarely ever a problem because of another system used on the Airbus known as flex temperature. Now, I have mentioned this before in some of my other videos, which is why you should definitely subscribe to the channel if you haven't already. So, go on, do it, click on it. Good stuff. Anyway, to keep it short, in order to artificially limit the available takeoff thrust, the pilots can calculate a flex temperature, which they will then input into the flight management computer. That temperature will essentially trick the engines into using less thrust, just enough to still

7:39 fulfill all of the various takeoff performance limitations, but not more than that. This has the added benefit of reducing the wear and tear on the engines, as well as minimizing fuel consumption and noise. So there is really no downside to it. On the Boeing, we use a similar system known as assumed temperature as well as a couple of fixed drates. So basically downgrades the engine thrust output by fixed amounts. But the idea is essentially exactly the same. Now there are times when we don't drate, for example, if there is windshare reported or in case of a contaminated runway. But in most other cases, it's highly recommended to use these techniques. So, back in the cockpit of Air France Flight 1414, the

8:24 two pilots had now come up with a more interesting idea. They were going to do a full thrust takeoff instead in order to practice this unusual scenario and get some more exposure to it. And also, I'm guessing because it's a lot of fun to do. A light aircraft on full thrust will accelerate like a race car. And that's obviously something that most of us pilots really enjoy. But because of the various threats associated with this, the first officer also included this in his briefing. That included the much higher acceleration, much more than than they were normally used to, as well as the need to keep a higher pitch up attitude after takeoff and a quicker than normal acceleration during the flap retraction. Now, up until this point, I can kind of understand what the pilots

9:10 wanted to do here. It is important that we pilots try things out from time to time in order to get practical experience of the aircraft in its full flight envelope and as long as it's properly briefed and the weather and traffic situation permits it, well then it shouldn't really create any real issues at all. So once the briefing was complete, the two pilots finished up their checklists, the cabin crew closed the doors, and soon the aircraft was pushed back from its gate and started taxing out to watch its departure from runway 27 left. During their 10-minute taxi out to watch the holding point, everything was completely normal. And after a very short delay, flight 1414 was then cleared for takeoff and started accelerating down the runway. Now, from this point on, things will start to get

9:55 really interesting, and I will tell you all about that after this. I want to share something that really caught me off guard recently and ended up unlocking stories about my family that I never heard before. It all started when I began digging into my family tree using My Heritage, today's sponsor. My family means everything to me and it is relatively small, so I've always been curious to know if there is more around. With My Heritage, you can build out your family tree, explore your heritage, and even discover relatives you didn't know you had. I started out simple by just adding my parents and grandparents. But as soon as I did, my heritage then started matching my tree to others that they had on record. And that's when it started to get really interesting. I

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11:27 in a way that is both simple and surprisingly emotional, I highly recommend giving My Heritage a try. Thank you, My Heritage. Now, let's continue. The initial part of the takeoff proceeded completely normally, and the first officer soon rotated and started pitching up to hold the normal speed. But, like I explained earlier, they were now flying with way more thrust than they actually needed. So he soon found himself also having to pitch up more than he normally would. The flight director stopped indicating higher at 18° for the reason that I explained before. But with that pitch, the speed just kept rising. So the first officer therefore continued to pitch up outside of his flight director in order to still keep that speed of V2 + 10 which he was used to. 5 seconds after

12:14 takeoff, the pitch was therefore at 19.7 degrees. And the speed reached a maximum of 147 knots. Now, that's higher than the speed they wanted, but still well inside of the normal speed envelope and far away from any maximum speeds for the flaps. But the first officer still continued to pitch up. 6 seconds later, the attitude had reached 24.6° with the first officer still inputting 11.7° pitch up on his side stick. And here another feature of the Airbos's fly by wire system now kicked in. You see, like I mentioned before, pilots rarely allow their aircraft to pitch up higher than 20° during normal operations. And actually, any pitch above 25° used to be part of a definition of an aircraft upset, which would require the crew to

13:00 execute an upset recovery procedure. Now today that definition has been updated to also include intent but the old definitions are deeply ingrained in most experienced pilots. Because of that Airbus has also implemented a nose up protection protocol which limits the nose up pitch angles that a pilot can select to different values depending on what configuration that the aircraft is in. In this case, since the flaps were still extended, the aircraft was now pitching high enough to activate this protection, which meant that the flight directors now disappeared. But that still didn't stop the first officer from inputting even more nose up inputs on his side stick. And that activated yet another Airbus protection system, a system that you

13:47 might have heard of before, but likely not in this particular context. You see, the Airbus has a system known as alpha floor protection, which is normally used to make sure that the aircraft doesn't exceed certain high angles of attack. The angle of attack is the angle between the wing's cord line and the oncoming air. And it's this angle who effectively decides when a wing stalls, meaning when it stops being able to effectively create lift. The alpha floor protection feature is programmed to help stop the pilots from even getting close to that critical angle of attack by limiting it to 9.5° in configuration zero, 15° in configuration one and two which they were now in and so on. And this activation angle is also known as alpha

14:32 pro. Now this aircraft was nowhere near that angle of attack. But as it turns out there is also another criteria for the activation of the alpha floor protection. It turns out that if the pilot's side stick is deflected to more than 14 degrees back stick and one of the two protections nose up attitude or angle of attack is also active well then the alpha floor will also activate and since those criteria were now met due to the high nose attitude and back stick input the aircraft momentarily went into alpha floor protection. The way this would have been shown to the pilots was primarily by an annunciation on their flight mode annunciator on their primary flight display. The pitch increase would then have also been stopped at the current value until a further nose up

15:18 input would have been made and the thrust would have gone into full toga mode with toga lock shown on the FMA. In this case, the alpha floor protection only activated for about half a second. So the pilots likely never saw it, but the toga lock would stay engaged until the pilots disengaged the outer thrust, selected climb thrust, and then re-engaged it again. And in this case, the thrust was already in toga since the pilots had taken off with full thrust. And that meant that there wouldn't have been any noticeable change in the thrust. So it is likely that the sudden Toga lock indication was the only clue that the pilots had about what had now happened to them. About 13 seconds after the activation of the alpha floor, the first officer disengaged the outer thrust using the outer thrust disconnect

16:04 switches on the thrust levers and eight seconds later he then re-engaged it again using the button on the glare shield in combination with moving the thrust levers into the climb detent. This reset the system and the pilots then continued to accelerate the aircraft to retract the flaps according to the schedule and then continue their climb up towards the cruising level without anything else happening. But they both knew that the activation of Togalock had not been normal and they therefore likely discussed the reason for this happening as they were continuing their flight. In any case, the rest of the flight continued normally and since this was a pretty short leg, it's unlikely that they had much time to consult manuals or to give this much more detailed thoughts. The first officer instead started setting up

16:50 the aircraft for the coming approach. And 1 hour and 1 minute after they had taken off, air flight 1414 landed safely on Siri runway 06 and then taxied into the terminal. Now this was obviously not a big deal, right? A system had activated and given the pilot some strange indications, but the safety of the flight was never really in jeopardy. That's all correct. But for any pilot worth their salt, they would never be happy about the aircraft doing something that they just didn't understand. Part of our job is to always maintain situational awareness which includes everything including technical situational awareness. So these two pilots now really really wanted to figure out what it was that they had experienced. Anyway, after they had shut

17:38 down the aircraft on the stand in Surirk and all of the passengers had disembarked, the first officer received a call from the Air France operations control who asked if he would be willing to conduct what's known as a ferry flight 2 days later between Tulus and Paris. A ferry flight is when an empty aircraft needs to be moved without passengers from one airport to another. And given that this was from Tulus, the home of Airbus, it was likely after some kind of maintenance. But the final report didn't really specify that. The first officer agreed, but he also asked if the company had selected a captain for the flight yet. And when the ops controller said no, he asked his friend, the captain, if he would be interested in doing this flight together with him. The captain agreed and the first officer therefore suggested this to operations who also thought that this would be a

18:23 great idea. So this meant that the same flight crew would now be flying together again with an empty aircraft just 2 days later. Now, I'm guessing that some of you can see where this is going, but I just want to stop here and explain how we pilots are supposed to troubleshoot tricky technical issues if we might come across them. First of all, we have our manuals. And by flipping through those, we can normally solve around 90% of all the doubts that we might have. In this case, they likely also had electronic flight bags, meaning tablet computers, containing all of their manuals and charts in digital formats. So a simple search for toga lock in their FCOM would have given them all conditions needed for this particular message to appear on their FA and from there they could have

19:10 then deduced the fuel reason behind it. But if that would fail, most airlines also have technical support channels where the pilots can send in queries. And if that still wouldn't help, well then we do recurrent simulator training every 6 months in which a specific scenario can easily be recreated. But that's not what these two pilots decided to do. Fast forward to the 30th of March and the pilots were now in the crew room in Tulus preparing for their ferry flight over to Paris. The weather was once again quite nice with only some few clouds at 10,000 ft and there were no nots or technical issues recorded on the aircraft. This time they would be flying a beautiful Airbus A321 which is a significantly bigger aircraft than the baby bus A318 that they had flown on the

19:58 days before. Now pilots with type ratings on the Airbus A320 family can fly on all of these variants within the scope of that same type rating. And because Airbus is using flybywire technology for their flight controls, all of these aircraft should handle in very similar ways. But there are still some differences. For example, since the Airbus A321 is significantly longer than the A318, it comes with a bigger risk of tail strike during the rotation. So, when the pilots had walked out to the aircraft and verified its technical status, the captain, who was now going to be pilot flying, briefed the first officer about this and said that they would limit the initial rotation to 7.5°. But he also added that this would be the chance they had to try to

20:43 recreate that strange indication that they had experienced on the flight before. So in order to do that, he decided that they should also once again execute a full thrust takeoff, this time with a completely empty aircraft. Now from a procedural standpoint, there are no differences between how we pilot should handle a ferry flight from a normal passenger flight. There are some extra steps we have to do since there are no cabin crew on board. The pilots will have to close and arm the doors for example and we also have to secure the gallas to make sure that no trolley will come shooting down the aisle during landing which actually has happened. But apart from that the procedures and rule stays exactly the same. Having said that though, the atmosphere in the flight deck can become quite a bit more relaxed

21:30 in these situations, and it is not unheard of that pilots might try things out a bit more when there are no passengers around whose comfort needs to be taken into account. A very tragic example of this happened on Pinnacle Airlines flight 3701, which I've also covered on this channel, and if you want to see that one next, then I will link to it in the end of this video. In any case, the pilots had soon completed their pre-flight and therefore started taxing out towards the holding point for runway 14 left, this time would call sign Air France 372 Victor. Once the before takeoff checklist had been completed, the first officer advised to lose tower that they were ready for departure and they were subsequently cleared for takeoff from 14 left with only mild winds reported. So at time

22:15 1752, the captain moved the aircraft into position, stabilized the engines, and then moved the two thrust levers into the toga. heat tent and that now caused the completely empty aircraft to literally jump into action and quickly accelerate down the runway. The captain then carefully rotated even though with this weight and thrust it would have been quite hard to actually tail strike it, but he then continued to pitch up just like his colleague had done two days earlier. Initially, he pitched for 17°, but since the aircraft then kept accelerating to up around 160 knots, he continued pulling back on his side stick until the aircraft was pitching 24° nose up and his stick deflection was then passing 14°. This caused the aircraft to once

23:00 again activate the alpha floor protection as the aircraft climbed through around 750 ft and the engines also again went into toalok. But this time the pilot saw it happen even though it was only active for less than a second and they were now a lot quicker to disengage and re-engage the auto throttle again. The aircraft then continued climbing like if nothing had happened up towards their initial climb clearance of flight level 100. Now, so far you might not think that this was so bad, and in itself, I would agree that the aircraft was never in any real danger here, but the alpha floor protection has been added to the aircraft for a reason, and it's not the pilot's job to try and purposely push the aircraft into situations where its protections are activated. Yeah, sure, there are some value in actually handflying the

23:47 aircraft and seeing where the margins are so that we can fully take advantage of them if a situation put arise that requires it. But that's why we have simulators, not a $70 million aircraft. And another thing to keep in mind here is that when pilots push their aircraft outside of their own comfort zone and outside of what's covered by normal procedures, it can often have unintentional consequences and things can quickly start to escalate far outside of what the pilots initially intended. And what happened next on this flight is a great example of that. The aircraft just continued to climb and was soon cleared to continue up to flight level 140. As they approached flight level 100, the first officer contacted the next controller frequency

24:32 and advised them of their current clearance. He was then told by the new controller to continue their climb up to flight level 1 ner 0 and to maintain there. Now, generally speaking, there always tends to be a speed restriction of 250 knots or below below flight level 100 in most of Europe. And even though there are some exceptions to this, we all tend to apply this maximum speed anyway in order to improve our chances to see smaller traffic around us and to make life a little bit easier for ATC. Above flight level 100, however, there are generally no speed restrictions. So above that level, we always accelerate to our economic climb speed, which varies with weight, but tends to be in the region of 280 to 300 knots or so, depending on aircraft. The way this acceleration normally happens is by a

25:18 slight decrease of climb speed in favor of acceleration. But we rarely completely stop our climb. Instead, we tend to go down to maybe 500 to 800 ft per minute or so. But that was not what the Meraki controller now saw this aircraft do on his radar screen. Instead, flight 372 Victor seemed to temporarily level off at flight level 100 and then its speed started increasing rapidly towards 350 knots indicated. The controller called the aircraft up and asked, "A France 372 Victor, what altitude are you crossing at the moment?" And the first officer replied, "Uh, flight level 100, Air France 372 Victor." The controller then continued with, "Did you level off or not?" likely asking this because the

26:04 controller are counting on us climbing or descending continuously. So these pilots would have needed a clearance to level off. But in any case, the first officer then replied, "Uh, no, we accelerated at flight level 100. Air France 372 Victor, we are climbing now." And seconds later, the aircraft speed trend started reversing and was instead replaced by an absolutely insane climb rate, shooting up with over 15,000 ft per minute. Now, there is no other word for what the pilots were doing here other than playing around. You see, an aircraft can store its energy in three different ways. The most obvious is chemically, meaning in its fuel, and that's what we are normally using to get ourselves from A to B. But the two other

26:51 ways are in potential energy, altitude or kinetic energy, speed. Those two last energy forms are almost directly interchangeable, meaning that we can exchange one for the other. And this is something that we instructors spend a lot of time showing new pilots, especially during descent planning. You see, we often get told to level off our descents at certain altitudes by air traffic control, which is a problem because we are following a pre-planned descent path down towards our airport. But as long as we continue to decelerate as we wait for our further descent clearance, we can then just tell the aircraft to use the coming descent to accelerate back to our previous speed once we get the clearance. And by doing that, we will end up exchanging

27:38 potential energy for kinetic energy and end up almost exactly on the same path. Like I said, this takes a little bit of explaining to do, but what these pilots were now doing was the complete opposite of that. They intentionally leveled off at flight level 100, but kept the trust in climb thrust, meaning that the aircraft quickly started to accelerate. They then allowed the acceleration to go all the way up to the aircraft's maximum certified speed of 350 knots before selecting open climb and a new speed of 220 knots. The result of that was that the aircraft started raising its nose and climb as quickly as it could in order to decelerate back those 130 knots that the pilots had asked for,

28:23 exchanging kinetic energy for potential. And since it was completely empty, this now led to a climb speed that we normally only see in fighter jets. So why was this such a big deal then? Well, like I said, unintended consequences. You see, in that same area, another aircraft was now cruising along happily at flight level 400. That's about 40,000 ft, meaning 21,000 ft above flight 372 Victor's clearance. But because TASS, the traffic collision avoidance system, is programmed to track all transponders around and activate if something could be a potential collision threat, the TAS system in this aircraft now activated and alerted its pilots to

29:08 a potential traffic conflict 25,000 ft below them. Now, it didn't issue a resolution advisory, which is when the pilots would have actually had to maneuver, only a traffic warning. But the two pilots in our Airbus cockpit had no idea about this because their TAS did not activate. The reason for that is that the TCAST system deactivates all of its warnings if a climb rate of more than 10,000 ft per minute is sensed. Something that these two pilots had no idea about. Now, I have been searching for the explanation behind this feature. And the best that I've been able to find is that the TKAS system knows that a climb with more than 10,000 ft per minute is not normal nor sustainable. And that it therefore has to be due to

29:54 either some kind of emergency or the initial takeoff phase with an extremely light aircraft. And in neither of those scenarios should the pilots be bothered with even more warnings. Now, there might be more technical explanations behind this. And if you have one, please let me know in the comments here below. And don't forget to like and subscribe while you're down there. Anyway, the controller who had seen both the level off and the following extreme climb rate now quickly called up the aircraft and told them to please reduce your climb rate because you're causing all systems to flush here. What he meant by that was not further elaborated on in the final report. But it is likely that this enormous climb rate which had caused the other aircraft TCAST to activate now

30:39 also warned the controller of this potential conflict or it was just highlighted on his radar screen as something really unusual. The pilots responded to this and the climb rate was quickly reduced. And after that, the aircraft autopilot successfully captured flight level 190 without any kind of problem or overshoot. And flight 372 Victor continued climbing normally towards its cruising level. The rest of the flight continued without any further shenanigans. And after 1 hour and 2 minutes, the aircraft landed normally on runway 08 right at Paris Shell de Gaul airport and then taxied into its stand. Now, it is unclear if it was the crew who reported this or if these two incidents were highlighted by the company's operational flight data monitoring system, but we do know that

31:26 the cockpit voice recorder was overwritten. So, this report is based on the flight data recorder as well as subsequent interviews held with the two pilots. The conclusion of the report was that even though it's not a bad idea that pilots practice certain maneuvers in the aircraft, it's probably better to use simulators for these kind of things or to utilize the technical support that they had available to them. It was also apparent that the two pilots did not understand the full consequences nor technical implications of their actions as clearly indicated by that rocket ship climb and that just further pointed in the same direction. Now, nothing really dangerous did happen on these flights, but if the same thing would have happened in a more densely trafficked area, the outcome might have been very

32:13 different. And a later BA report about a different Air France incident actually used this report as an example of pilots not following standard operating procedures. Now, I love covering incidents like this because there is so much to learn from them at the same time as no one is being hurt in the process. I personally wanted to lift these two incidents because similar kind of behavior has happened before with far worse consequences. And if you want to see just how bad it became, then check out this video. Now, if you want to see my next video before anyone else, possibly even today, well, then use this QR code or go to patreon.com/join/mentorpilot. I would love to see you in my next Patreon

32:59 hangout, but you can also support what we do here by using the special deal from our sponsor in the description and the pinned comment below. My name is Peter Hornfeld. You are watching Mentor Pilot. Have an absolutely fantastic day and I'll see you next time. Bye-bye.