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I was on a flight recently and the plane started to descend normally etc. However one cabin crew member randomly announced "remember if we have an emergency landing please leave all your belongings behind". I know this is said on auto announcement but I have never herd it said on a descent.

Anyway, suddenly the plane was going down nose down, controlled but lots of stuff rolled to the front. Several people were looking scared and I really thought/ knew it should not be nose down! This lasted about 1 minute and it then leveled out and landed fairly normally.

If that announcement wasn't made I could tell myself it was one of those things but cabin crew never let on and now I can't fly again but actually need to! I really thought we were crashing. Aircraft sounded normal but when it was nose down it was like the engines had gone really hushed.

I checked flightradar24 after we landed and there was a brief message flashed up that our flight was alerted by such and such a flight.. we landed at Newquay. The flight number was FR2954 on 12 Sep 2021 (ALC - NQY 03:40).

Can anyone say why this happened? I'm still shaken as I was always a terrible flyer. Something went on with that flight. I fly about 8 times a year and that has never happened! Why was the announcement made and why did the plane descend nose down?

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    $\begingroup$ Welcome to the site. Airplanes always descend by throttling back the engines and putting the nose down, it really can't be done any other way. I believe you when you say it was more exciting than usual, and it is unusual for them to remind people to leave their bags behind at that phase of the flight so it's possible the airplane experienced an emergency of some kind. Please keep in mind it was all fine in the end, chances are they were acting out of an abundance of caution. $\endgroup$
    – GdD
    Sep 14 at 7:27
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    $\begingroup$ @GdD: Actually it can. If you've taken flying lessons that involved stalls, you've probably done an extreme version of it: point the nose up until you're on the edge of stalling, then add power to stay stable. You can vary the power to climb or descend, And pretty much all airplanes do the last part of landing in a nose-high attitude. In a single engine plane, nose down landing can get you a prop strike. $\endgroup$
    – jamesqf
    Sep 14 at 16:13
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    $\begingroup$ @GdD: But you wrote AIRPLANES, not airliners. Airliners are only a small subset of airplanes. I doubt whether many of us here fly airliners, or ever want to. (Comments from actual airline pilots would be welcome :-)) I've certainly seen airliners descending in a nose-up attitude, and certainly they nose is up at touchdown - do a search for pictures. $\endgroup$
    – jamesqf
    Sep 15 at 3:32
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    $\begingroup$ @EliseBarker I’ll just point out that your flight had a (brief) moment of something slightly unusual happening and landed 100% safely and normally. If anything, it sounds reassuring to me that something can be different, and it’s still incredibly safe! $\endgroup$
    – Tim
    Sep 15 at 8:44
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    $\begingroup$ AIrcraft usually land into the wind, but your flight landed with a ~5kt tailwind. My hypothesis: The crew may have planned the descent profile so that they would fly past the airport, turn and then land into the wind. At some point they discovered that a straight-in landing would result in an acceptable tailwind. This reduces track length and therefore flight time, but it also meant a steeper descent. The descent speed peaked at over 4000 fpm, which is very high for airline operation. $\endgroup$
    – DeltaLima
    Sep 15 at 23:15
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Nothing out of the ordinary here. You probably arrived at the airport a little bit earlier because ATC allowed your plane to go directly to the runway instead of taking a longer route (as confirmed by the radar data from FlightRadar24). It was probably a quiet moment at the airport and there was no need for your plane to fly to the back of a queue.

Since you were allowed to fly straight to the runway, there was less time to descend, so the descent was a bit steeper than what you're used to. If you're descending steeply, the engines are not needed to maintain speed, and they go really quiet. However, in all likelihood, the only reason they did a steep descent is because they wanted you to get to your destination quicker.

If there's an actual emergency, it is in the crew's best interest to tell everybody. They prefer people to be prepared, even if that means some people may panic. So unless they tell you, there's no emergency. Perhaps they remembered they forgot a part of the safety briefing at takeoff. Or they had some passengers overly protective of their hand luggage (the type that refuses to store their luggage in an overhead compartment six feet away). Unless you asked the crew, we can only guess.

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    $\begingroup$ Sorry, I misread the question. But either way, I think you have no reason for concern. The number of pilots on the flight has no bearing on the safety of the flight. $\endgroup$
    – Sanchises
    Sep 14 at 9:05
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    $\begingroup$ @Sanchises . The number of pilots on the flight has no bearing on the safety of the flight., true only for 'n >= 2' $\endgroup$ Sep 14 at 15:18
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    $\begingroup$ The last few minutes of the flight are pretty busy for the cabin crew; if they were expecting to land at time T, and found out at T-20 that it would actually be T-10, then all that work needs to get compressed by 50%. An overall air of urgency will prevail. The minimal announcement about not trying to bring your stuff is probably mandated by regulations, so can't be skipped, even if it comes out hurried and breathless. $\endgroup$
    – CCTO
    Sep 14 at 15:36
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    $\begingroup$ @manassehkatz Really, n!=0. All modern planes can be flown by a single pilot if necessary. $\endgroup$
    – Sanchises
    Sep 14 at 18:00
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    $\begingroup$ @Sanchises I contemplated 'n >= 1'. But while any modern plane can be flown by a single pilot, my understanding is that even in normal (let alone "something suddenly going wrong") situations, both pilot and co-pilot have plenty of things to do during approach & landing. Arguably having only 1 available pilot (due to incapacitation of the other one for any reason) in an airliner that requires 2 pilots for normal passenger operation is "less safe". $\endgroup$ Sep 14 at 18:03
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According to FlightRadar24 here:

here

at one point your flight was descending at more than 4000 feet per minute. This is a bit faster than usual, especially for the (relatively) low altitude you were at at the time.

However, that is still well within the normal safe flying capabilities of the 737. In an emergency, when the plane needs to get down fast, they will descend at up to about 7000 feet per minute, potentially faster depending on some variables. However, pilots know that fast descent rates are uncomfortable for passengers and are not the most efficient way to fly. So they avoid them whenever they can.

Why did your plane descend faster than usual? I can't be certain but it might be due to a late change of runway direction or traffic conditions, meaning they didn't have as many "track miles" to lose the altitude as they planned. But what they did was a very safe manoeuvre. Whatever the reason, I can pretty much guarantee it was unrelated to the announcement, which was just unfortunate timing.

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    $\begingroup$ @EliseBarker The fast descend was down to 10,000 ft according to the vertical profile shown in FR24. The tallest mountain in the UK (Ben Nevis) is only 4,411 ft tall (and far away from your flight). So there was definitely no hill anywhere close. $\endgroup$
    – Bianfable
    Sep 14 at 9:07
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    $\begingroup$ One thing to keep in mind, most people sitting in the cabin really have no idea what the nose (pitch) is doing unless they look outside. An aircraft isn't just a floor that tips. A pilot can make every loose item in the cabin roll forward simply by slowing down quickly. It's a trick of physics used in amusement park simulators. New pilots fall victim to this trick if they fly into a cloud and ignore their instruments. They keep making adjustments so they feel gravity below them. But gravity feels like any other force so many new pilots fly out of their first cloud completely upside down. $\endgroup$ Sep 14 at 21:07
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    $\begingroup$ @user253751 the artificial horizon is the instruments. The problem with "feeling gravity" is that a slanted bank combined with sight pitch up will feel like gravity, but keep doing that and you'll eventually be upside down relative to the earth but still feeling the gravity. You can actually fly a plane into the ground and never sense that you're upside down. $\endgroup$
    – Nelson
    Sep 15 at 2:42
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    $\begingroup$ @user253751 Here's a video the Australian aviation regulator released on it: youtube.com/watch?v=pc9xI4kpY4w It's titled "178 seconds to live" for a reason. $\endgroup$
    – nick012000
    Sep 15 at 3:51
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    $\begingroup$ @EliseBarker don’t listen to the other passengers. 99% of them have no idea about the safety of airplanes, and the 1% won’t be gossiping about hills 😀 $\endgroup$
    – Tim
    Sep 15 at 8:46
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The economics of descent planning

Normally the pilot wants to descent in an economic manner and also try to keep passenger comfort in mind. Let's start with the "economic" descent: An airplane will generally consume least fuel per distance at its "optimum cruising altitude". The exact altitude is dependent on the type of plane, the wind and weight. For a jet like the 737 you flew with it is safe to assume that this optimum altitude is >FL300 (so above 30,000ft / 10km). In cruise your flight was at FL400 so that was probably near the optimum for your specific flight on that day.

As soon as you start your descent to your destination you are leaving that optimum altitude. This is bad. So you want to start your descent as late as possible.

On the other hand, at the end of your flight you still have some "free energy": The potential energy conserved in your altitude. You also want to use that energy as good as you can. Using that energy means to turn your plane into a glider. Theoretically you shut down the engines and glide down to your destination (in reality the engines are not shut down but just set to the lowest possible thrust setting).

Those two factors give you an optimal "top of descent": The point at which you can reduce thrust to minimum setting for the remainder of the flight and still reach your destination by flying with "best glide speed".

Now in reality this is disturbed by a few factors. Mostly "other traffic" is such a factor. Maybe you cannot start your descent at your preferred location because there is traffic below. Or maybe you expect a certain routing, start your descent at the correct place, but then in the middle of the descent ATC gives a you different routing which maybe a shortcut or a detour. In this case you are now "too high" or "too low".

Your particular flight (undesired level off)

In the case of your flight you can see a suspicious "level off" at about 15:29 in FL280:

speed/altitude graph of FR2954 on 2021/09/12

It is highly likely that the pilots were on their desired flight path, but air traffic controllers did not allow them to descend any further. The most likely reason for this is crossing traffic, but it could also have other reasons like late coordination between controllers etc.

Fixing the undesired level off

Anyhow, what can you do as a pilot in such a situation? You will need to use engine thrust in order to stay in FL280. Then once ATC allows further descent you will be too high due to your level off and you need to somehow get rid of the additional energy you have. From an economic perspective this is really bad, because you are burning fuel unnecessarily.

But the pilot is not powerless. There is a third resource you have: Your speed. In such a level off you can reduce the speed in order to leave your engines at idle (or at least a low setting). Actually you can see a pronounced drop in airspeed on your particular flight, so that is probably what the pilots did.

Then when ATC finally allows further descent, you are now too high and too slow. So it is time to trade altitude for speed. And that will result in a nose down attitude. The pilot with high passenger comfort awareness will do do this trade slowly, gradually picking up speed. However the more economic way is to do this quickly.

Additionally it may well be possible that the pilots could not reduce the speed as much as needed in order to conserve their desired state of energy. Maybe they needed engine thrust nevertheless. In this case even after trading altitude for speed they are still too high. They now need to get rid of this energy somehow. One way to do so is to use the speed brakes. However braking away the energy means the extra energy just goes to waste. Another option is to just fly faster. If you fly faster air resistance increases exponentially, thus you will also waste some energy, but at least you also get a benefit from that procedure: You'll reach your destination earlier. So the pilots might want to fly even faster than normal and that means an even steeper descent.

Managing passenger comfort while trading altitude for speed

In this situation it is likely that the AP (Autopilot) was engaged. In that case the comfort depends on the programming of the AP and inputs the pilot makes. The "simplest" mode would be "level change" (Boeing, on Airbus the equivalent would be called "open descent") and at the same time set a high speed target for the AP. In this case the AP will set engines to idle and then pitch down in order to gain speed. How much the AP pitches down depends primarily on the difference between current speed and the target speed. It is completely safe to engage "level change" mode and immediately set a very high speed target. But it can lead to an uncomfortable pitch down as you have experienced.

There are a few tactics to make this more comfortable. One way is to engage "level change" but gradually increase the speed target for the AP. The speed will build up slower, but the pitch will feel much more comfortable. Another option is to not use "level change" mode but "vertical speed" mode. In this case the pilot typically sets the speed target to a very low value (so that engines are idle) and then set a defined rate at which the plane should descent. This also causes the plane to pick up speed (if the vertical speed target is set high enough) but this happens much smoother. However it also means that the resulting speed is not controlled by the AP anymore. The pilot needs to closely monitor the resulting speed and readjust the vertical speed as needed.

As a side note, if a pilot is new on that particular airplane type (or AP) or did not have such a situation for a long time it may also be that the pilot is surprised by how strong the AP pitches down and might manage this differently the next time. However this does not make the situation unsafe. In a comment to another answer you wrote that there were two co-pilots on board. This MIGHT indicate that this was a training flight. On the first flights of a new co-pilot an additional "safety pilot" is in the cockpit to monitor and assist or (in worst case) take the position of the new pilot. This would support the theory that the extend of the pitch down might have been unintentional.

Conclusion

To conclude: The descent your experienced was likely the result of an ATC descent restriction. The maneuver was safe and probably the most economic thing the pilots could have done. However more comfort would have been possible and the pilots probably put put economic or workload concerns before passenger comfort. At any rate it is unlikely that there was any danger.

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    $\begingroup$ Might be worth stressing, that the possible crossing traffic and air traffic control restricting the movement of the aircraft is by no means unusual or risky. It is totally normal and everyday life on the line. $\endgroup$
    – Jpe61
    Sep 15 at 7:54
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    $\begingroup$ Thanks for taking the time to explain things . Up until about 16 I was fine with flying but then had a break for several years until 6 years ago and I suddenly went in to terrified mode while waiting to get on the plane. .. in a nutshell it took 5 years and numerous sedatives ( never worked ) to build up some confidence and I was doing really well. Never liked take offs but I was ok during the flight until that nose dive !! everyone who replied has made me feel confident enough to fly again I hope, and I am really glad I found this site. I googled for hours ! $\endgroup$ Sep 15 at 15:26
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    $\begingroup$ @Elise if you broadly studied accidents in all travel modes, and let accurate data guide your thinking... you'd feel safe as houses inflight... a little bit watchful when the airplane is on the ground... but you'd never step into an automobile, again, ever. $\endgroup$ Sep 16 at 22:24
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lots of stuff rolled to the front

This is a sad but common indicator of how ignorant your fellow passengers were.

Because most people have understandable concerns about being a mile up in a tin can, airlines make the interior feel "homely" and safe. As a result, people treat it as if they were sat in their armchair at home. They aren't, and this is dangerous. If you're driving, you should naturally be aware that random unsecured stuff will fall around when you accelerate, brake or corner; but people seem to forget that this is going to happen in a plane as well.

This is why flight attendants are vital members of the crew when it comes to keeping everyone safe. There are always a few idiots who think it's perfectly fine to leave bottles, handbags or whatever rolling around on the floor.

I really thought we were crashing

And again, this is a sad but common indicator that people don't actually know what flying feels like. The worst way to be scared is to not understand what's going on, and being a mile up in a tin can isn't anyone's natural environment. If your only experience of driving was up and down a 100-mile straight stretch of highway, then braking for traffic lights would feel like you're crashing too - even though it's just normal driving. That's where you are right now.

If you want to be less scared as a passenger, go up for an air experience flight in a small plane or a glider. If you pick the right one, you'll even get to fly the plane yourself for a bit. Sat next to the pilot as they talk you through what they're doing, it'll give you a much better appreciation of what's actually going on. Then as a passenger in a larger plane, you're in a position to know what's going on and rationalise it to yourself, and that does absolute wonders for keeping yourself calm.

That bump and whirring from the wings after takeoff or on landing approach? That's the flaps, which you saw the pilot wind out manually on the smaller plane. A bit of turbulence on a warm day? Any small plane will be bounced around a bit with thermals, so you've been there and done that. Tight turns and the wings looking like they're right up and down? Small planes flick into turns way faster, and can easily turn way tighter. And because of the size of it, it feels natural rather than dangerous.

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    $\begingroup$ Taking a flight in a small aircraft where you A) sit right in the front looking out the front windows (which you cannot do in an airliner), and B) can talk to and watch the pilot (if he's calm, you should be too), is an excellent suggestion! $\endgroup$
    – FreeMan
    Sep 15 at 13:44
  • $\begingroup$ Do you have any evidence that leaving an object as small as as a water bottle loose is dangerous? How about in the absence of turbulence? $\endgroup$ Sep 16 at 22:00
  • $\begingroup$ @AnonymousPhysicist Many people have glass bottles, bought in the terminal. So my evidence is every person who's ever cut themselves on a piece of broken glass, since the invention of glass. ;) $\endgroup$
    – Graham
    Sep 16 at 22:26
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    $\begingroup$ @AnonymousPhysicist : end of dinner one third into the 12 hours night flight, a small glass bottle of wine opened on my aunt's tablet next to me, so I signaled her, but she was so busy enjoying her meal. 2 minutes later, level change, B77W burned enough fuel to climb from FL330 to FL370 and some hazy glows of beacon light outside tells you there are cirrus clouds. Yeah, turbulences, the bottle tipped, now she's covered in blood red. The danger was not the bottle, it was she panicking, though, the bottle rolled somewhere only one flight attendant knows where when we asked for towels. $\endgroup$ Sep 16 at 23:40
  • $\begingroup$ @Graham People can also get cuts from glass bottles that are not loose. $\endgroup$ Sep 17 at 12:05
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I've had this happen for urgent situations, where it's important to land quickly even though nothing is wrong with the plane.

One time: there was a strange rattling noise coming from the cargo area. We made an unplanned landing in a different country so they could investigate. It turns out some type of hose had come loose, nothing dangerous.

If there's a medical emergency, they'll also want to land quickly.

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    $\begingroup$ When we had landed nothing happened as in people being rushed off or anything like that! im very ignorant about the hows and whys of flying but my anxiety is now cruising at about 80,000 feet! i do remember I immediately went on FR24 and a pop up said something like " your flight was alerted by.." and then the flight that did the alerting was highlighted around the sea off South Wales.. I'm none the wiser but it was horrible not knowing and Im grateful for all the lengthy replies from everyone.. $\endgroup$ Sep 15 at 15:20

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