What Everyone Gets Wrong About Planes
Summary
TLDRThis video delves into the science behind commercial flight, addressing why plane doors don't need locks due to pressurization, the economic and safety reasons for flying at high altitudes, and the efficiency of jet engines at such heights. It also touches on the history of electronics use on planes, the myth and reality of airplane mode, and the peculiarities of taste and smell at high altitudes. The script concludes with a discussion on the impact of climate change on flight turbulence and the importance of critical media analysis.
Takeaways
- 🔐 Most airplane doors aren't locked during flight due to the significant pressure difference between the inside of the pressurized cabin and the outside environment.
- ✈️ Airplanes typically fly at around 30,000 to 40,000 feet (9 to 12 kilometers) for reasons including smoother air, fuel efficiency, and avoiding weather-related turbulence.
- 💸 The main reason for flying at high altitudes is economic, as reduced air density allows planes to fly faster for the same amount of thrust, leading to fuel savings.
- 🌡️ At high altitudes, the temperature is much colder, which increases the efficiency of jet engines that perform better in colder air.
- 🛫 The pressurized cabin is crucial for passenger safety, as the air at cruising altitudes is unbreathable due to low air pressure and oxygen levels.
- 🚪 The design of airplane doors has evolved to be plug-like to create an airtight seal against the high pressure inside the cabin.
- 🌬️ The pressurization of airplane cabins is set to a level that balances passenger comfort and safety with the structural integrity of the aircraft, avoiding excessive stress on the aircraft's fuselage.
- 📵 The requirement for airplane mode on electronic devices is a historical precaution against potential interference with aircraft systems, despite modern evidence suggesting minimal risk.
- 🍽️ Airplane food may taste different due to the dry and low-pressure cabin environment, which can affect passengers' senses of taste and smell.
- 🌍 Climate change may contribute to increased turbulence, but media coverage of this topic can be sensationalized and should be critically evaluated for accuracy.
Q & A
Why are most plane doors not locked during flights?
-Most plane doors aren't locked because the pressure differential between the pressurized cabin and the low-pressure exterior at cruising altitude is so great that no one is strong enough to pull the door inward.
At what altitude do commercial planes typically fly, and why?
-Commercial planes typically fly at around 30,000 to 43,000 feet (9 to 13 kilometers). They fly this high primarily for safety, to avoid turbulence and storms, and for fuel efficiency due to the decreased air density at high altitudes.
How does flying at high altitudes affect the efficiency of aircraft engines?
-Jet engines are more efficient at high altitudes because the colder air allows for more efficient combustion. The air density is also lower, which means planes can fly faster for the same amount of thrust, resulting in less fuel consumption.
What is the role of pressurization in modern aircraft, and why is it necessary?
-Pressurization is necessary in modern aircraft to maintain breathable air inside the cabin at high altitudes where the air is unbreathable. It involves continuously bringing in air from the compression stage of the jet engines to maintain a breathable atmosphere for passengers and crew.
How does the pressurization of the cabin affect the design of plane doors?
-Pressurization affects the design of plane doors by making them wider on the inside than the outside, creating a plug-like shape. This allows the higher pressure inside the cabin to push the door into its frame, creating an airtight seal.
Why do planes not pressurize to sea level pressure?
-Planes do not pressurize to sea level pressure to minimize stresses on the aircraft's fuselage, which extends the life of the plane. Pressurizing to the minimum extent possible reduces the fatigue and cracking that can occur with each flight cycle.
What is the significance of the Aloha Airlines 243 incident in relation to aircraft pressurization?
-The Aloha Airlines 243 incident highlighted the importance of managing stress on aircraft structures due to pressurization. The plane experienced an explosive decompression after nearly 90,000 flight cycles, which was much higher than it was designed for, leading to fatigue, cracking, and corrosion.
Why do airlines ask passengers to switch their phones to airplane mode?
-Airlines ask passengers to switch to airplane mode to prevent potential interference with the aircraft's communication and navigation systems. Historically, there were concerns that phones could connect to multiple cell towers simultaneously, overloading the infrastructure.
How does the dry air inside an airplane cabin affect passengers' sense of taste and smell?
-The dry air inside an airplane cabin, which can be as low as 5% humidity, dries out passengers' nasal passages, hindering their sense of smell and therefore taste. This is why some flavors might seem bland or different in flight.
Why do some passengers report an increased desire to drink tomato juice or Bloody Marys on flights?
-The desire to drink tomato juice or Bloody Marys on flights might be due to the cabin noise stimulating the chorda tympani nerve, which could boost the sense of umami, a savory taste found in tomatoes and other ingredients. This audio illusion might make these drinks more appealing in flight.
Outlines
🛫 Aviation Safety and High Altitude Flight
The script begins by discussing the lack of locks on airplane doors and the rarity of them being opened mid-flight, despite the ease with which they could be. It then delves into the reasons behind planes flying at high altitudes, such as avoiding turbulence and weather-related issues. The conversation highlights the economic benefits of high-altitude flight, including reduced air density leading to increased fuel efficiency and speed. The script also touches on the physical properties of air at high altitudes, explaining how colder temperatures improve engine efficiency. The segment concludes with a discussion on the necessity of cabin pressurization due to the unbreathable air at cruising altitudes and the historical context of aircraft design changes to accommodate pressurization.
🚧 The Mechanics of Pressurized Cabins and Door Design
This paragraph explores the design of pressurized airplane cabins and the unique shape of aircraft doors, which are wider on the inside to create an airtight seal when the pressure inside the cabin is higher than outside. It explains how the pressure difference prevents the doors from being opened in flight. The script also discusses the airtight nature of cabins, the impact of cabin pressure on objects like chip bags, and the historical context of pressurization and its effect on aircraft fuselage integrity. The narrative includes a real-life incident where a passenger managed to open an emergency exit due to the reduced pressure differential during final approach, emphasizing the importance of cabin pressurization levels in maintaining safety.
✈️ The History and Impact of Airplane Mode
The script addresses the requirement for passengers to switch their phones to airplane mode during flights. It recounts the historical concerns that led to the introduction of this rule, stemming from potential interference with aircraft navigation systems and cellular network infrastructure. The discussion points out the theoretical and practical limitations of these concerns, including the Faraday cage effect of the aircraft and the difficulty of establishing a connection between cell phones and cell towers in flight. The segment also speculates on the future of airplane mode regulations, with some regions moving towards allowing in-flight cellular connectivity, and touches on the impact of cabin environment on passengers' experiences, such as taste and the perception of food quality.
🌍 Climate Change, Turbulence, and the Future of Air Travel
The final paragraph shifts focus to the broader context of air travel, including the impact of climate change on flight conditions and the role of media in shaping public perception. It references a study suggesting a link between climate change and increased turbulence, which was overshadowed by other news events. The script advocates for a comprehensive approach to understanding aviation news and the importance of scrutinizing media coverage. It concludes with a call to action for viewers to use Ground News for balanced reporting and to support the channel through a subscription offer.
Mindmap
Keywords
💡Airplane Door Security
💡Cabin Pressurization
💡Altitude and Fuel Efficiency
💡Jet Stream Tailwinds
💡Emergency Exit Protocols
💡Oxygen Partial Pressure
💡Explosive Decompression
💡Airplane Mode
💡In-Flight Food and Taste Perception
💡Fatigue Cracking
Highlights
Most plane doors aren't locked and can be opened with the pull of a lever.
Planes fly at high altitudes primarily for safety and to avoid turbulence.
The height at which planes typically fly is around 30,000 to 43,000 feet.
Flying at high altitudes is more fuel-efficient due to lower air density.
Jet engines are more efficient in the cold air found at high altitudes.
Pressurized cabins are necessary at high altitudes due to unbreathable air.
Pressurization has led to a redesign of aircraft doors to create an airtight seal.
The pressure difference between the cabin and exterior prevents doors from being opened in flight.
Planes are pressurized to a level that minimizes stress on the aircraft's structure.
An incident in May 2023 showed that a passenger could open an emergency exit during final approach.
The FAA banned personal electronics on flights due to potential interference with navigation systems.
The theory that cell phones could overload ground networks has been questioned.
The EU is pushing for airlines to provide 5G service, potentially eliminating the need for airplane mode.
Airplane food tastes different due to the dry and low-pressure cabin environment.
Some passengers report an enhanced taste for certain flavors like tomato juice while flying.
The perception of flying is distorted due to media focus on accidents rather than the overall safety record.
Ground News provides a comprehensive view of news stories, including those related to aviation and climate change.
Transcripts
(brooding music)
- Most plane doors aren't locked.
There are no keys, no sensors or passcodes to secure them.
If someone wants to pull the lever, they can.
- A man opened the emergency exit door
and forced his way off the plane.
- And yet with 40 million flights each year,
these doors are virtually never opened in flight.
So, why not?
- Your self preservation, surely.
- Common sense.
- Most people are, you know, smart enough
to not mess with that.
- The real answer relies on where planes fly.
- How high do planes fly approximately?
- 10,000 km or is that overshooting it?
- I think that's overshooting it.
I think you'd be in space.
- 25,000 km.
That's the height of a plane flying?
- Is that way too low?
- It's too much. It's too much.
Too much. Too much.
Bring it down.
- Maybe yeah, 1,000 km?
- 1,000 km, still space.
- 50,000 ft, I think.
- Yeah, some of them can go up to 43,000 ft.
- 30,000 ft.
- 38,000 ft.
- Yeah.
Why do they fly that high?
Uhh...
- I don't know. Safety, I guess.
- Probably to avoid collision with other aircraft
and if there's high mountain ranges.
- I don't know, when storms or weather hit?
- My guess is to avoid the turbulent weather.
- I think that's a decent guess.
Now, it's true that one of the benefits
of flying at 30,000 ft is a smoother ride.
This is high in the troposphere,
the layer in which most weather occurs.
So, there's less turbulence
and fewer storms to navigate around.
But this is not the main reason that planes fly so high.
The bigger reason, of course, is money.
As you go up, the density of air decreases
and at 33,000 ft or 10 km,
the density of air is just a third
of what it is at sea level.
So flying at this altitude,
the plane runs into a third of the air molecules it would
closer to the ground.
That means the plane can fly about 73% faster
for the same amount of thrust.
And as a result, you get to your destination faster
and since you spend less time in the air,
you burn less fuel.
It seems in a way that like climbing is wasted energy.
Can you compare like the descent to the ascent?
Do you essentially get the energy back
as you fall down the other side?
- Yeah.
When we climb, we burn about 80 kilos per minute.
In cruise, we burn about 40 kilos per minute.
And in descent, it's maybe 10.
So, it's almost negligible.
- Not only that, jet engines are more efficient at altitude.
They work by compressing air at the intake,
mixing it with fuel and igniting it.
So, the combustion products are ejected very fast
from the exhaust nozzle.
Now, this process is more efficient the colder the air is.
And at altitude, the temperature
is around minus 50 degrees Celsius,
which is a lot colder than an average of plus 15
here at the ground.
So, flying higher means you burn less fuel for less time
and avoid the weather and associated turbulence
of lower altitudes.
- The other reason you wanna fly high
is to take advantage of the jet stream tailwinds
and the company likes people who do that,
because you're burning less fuel,
so it's less money.
- But there is a problem with flying this high.
The air up there is unbreathable.
If you were suddenly teleported
to the top of Mount Everest, a height lower than planes fly,
you would remain conscious for only about three minutes.
This is because in addition
to density dropping with altitude, so does air pressure.
Air pressure actually falls off faster,
because it depends on the weight of all the air above you.
So at 10 km, the air pressure
is only a quarter of what it is at sea level.
To be clear, the air is still 21% oxygen,
but the partial pressure of oxygen,
the pressure exerted solely by oxygen molecules
is around 5.5 kilopascals,
which is a quarter of what it is on the ground.
Now at this pressure, not enough oxygen molecules
can force their way into your blood in your lungs.
To function normally, humans need an oxygen partial pressure
of at least 16 kilopascals.
So, all the cabins of airplanes
that cruise at high altitude must be pressurized.
A little bit of air is continuously brought
into the cabin from outside.
It actually comes in from the compression stage
of the jet engines.
That is what maintains breathable air inside the plane.
- The downside is that you are taking away
a little bit of the efficiency of the engines.
- Now, pressurizing the cabin
required a radical redesign of aircraft.
Before pressurization, planes would fly
up to 10,000 feet or around three kilometers,
where the partial pressure of oxygen is 15 kilopascals,
just at the limit of what people can handle.
On these planes, doors opened outward
and there wasn't much concern about the seal around them
since the pressure was the same on both sides.
But once planes were pressurized,
all the doors were changed to be the shape of a plug.
They're wider on the inside than the outside.
That way the higher pressure inside the cabin
pushes the door into its frame, creating an airtight seal.
How airtight is a cabin?
- It's pretty airtight, but not completely airtight.
So, you'll notice for example,
every time that someone flushes the toilet,
you'll see some of the air pressure go down.
So every time that happens,
you can actually see the cabin altitude jump a little bit.
- And this is why plane doors and emergency exit doors
don't need locks.
The difference in pressure between the pressurized cabin
and the low pressure exterior is so great
that no one is strong enough to pull the door inwards.
And if someone had come up
and turned that while you're mid-flight?
Nothing.
- Even modern plane doors that open outward
are shaped like plugs.
They're just cleverly designed.
The main passenger door on a Boeing 737
is both wider and taller than the frame it needs
to pass through.
But when you pull the lever,
gates at the top and bottom fold in,
reducing the height just enough.
However, the sides are still too wide.
So, the door first has to pop inside and rotate.
It's that movement inwards that is impossible at altitude.
It would require a force equivalent
to lifting 9,000 kilograms.
And airplane cabins aren't even fully pressurized
to the sea level pressure of 101.3 kilopascals.
You may have noticed this
if you take a bag of chips on a plane.
It's easy to squish on the ground
but as the plane climbs, the pressure in the cabin drops
and the chip bag seems to inflate like a balloon.
I measured the pressure in my plane
and at cruising altitude,
the pressure dropped to 77 kilopascals.
Meaning the partial pressure of oxygen
was only 16 kilopascals,
the minimum required for people on the plane to feel normal.
This has some unintended consequences.
Do you think you fart more in a plane?
(interviewee laughing)
- If I did, I'd blame someone else.
- I feel like no.
- No.
- No
- I can't let it rip, no way in the world.
Do you think you fart more in a plane than on the ground?
- A hundred percent, no hesitation.
Sure, I mean it's gotta do with the cabin pressure, right?
- So as you go up, that cavity in here now expands
and the air wants to go somewhere,
and the quickest place it can go is south.
- Bag of chips just popped by itself.
- Now, the International Space Station is pressurized
to sea level pressure, 101.3 kilopascals.
So, why are planes pressurized
to the minimum extent possible
to carry human passengers?
Well, it's actually for a very good reason.
In 1988, Aloha Airlines 243
was en route from Hilo to Honolulu, Hawaii.
The cabin was being pressurized as we've described,
but unfortunately, this plane's fuselage had a small crack
and all of a sudden at 24,000 feet,
the crack widened and the whole roof
tore off the front of the plane.
Miraculously the pilots were able to land safely
and only one person was killed.
The difference between the International Space Station
and a plane is that the ISS was pressurized once
and it stays pressurized.
But a plane experiences a pressure difference
every time it climbs to cruising altitude.
So, the fuselage is stretched
and then relaxed with every flight.
Stretched and relaxed, stretched and relaxed.
The Aloha Airlines plane
had the second highest 737 flight cycle count in the world,
with nearly 90,000 in total.
That's way more than it was designed for.
This led to fatigue, cracking, corrosion,
and the eventual explosive decompression.
So, planes are pressurized to the least extent possible
to minimize stresses and extend the life of the plane.
But even 75% of atmospheric pressure
should be plenty to prevent the doors from opening.
So, how did this happen in May, 2023?
- A passenger panicked and actually managed
to open an Airbus emergency exit in flight.
They were on final approach
and they were quite close to the ground,
so the pressure differential was very little.
And because of him using all of his force,
he actually managed to get the door open, which was crazy
and we didn't think that that was possible.
But if you want something bad enough, I guess it is.
- Wow.
Was he okay?
- He was okay. Everyone was okay in that case.
- That was a pretty serious mishap.
So, I guess the next logical question is:
Have any other passengers inadvertently caused a mishap,
by say, forgetting to put their phone on airplane mode?
When you're sitting there on the tarmac
and they come on and tell you
to put your phone on airplane mode, do you do it?
And why do they get us to do that?
What is the reason? Is there a reason?
- Obviously, they wouldn't ask you to do it
if it wasn't for some benefit.
- I'm unfortunately a bit of a rebel
and I don't follow the rules and yeah.
- But you're not worried about taking the plane down?
- I'd make sure my parents have the airplane mode on
so I can have it off.
- I mean, yes I do because I don't want it interfering
with like the radio or whatever.
- Well, I think it's the communication interference.
- I feel like I've always been told
like it messes up like instruments,
but honestly you're always just told to do it.
So you know, just gotta put your phone in airplane mode.
- In 1961, the Federal Aviation Administration or FAA
found that some portable FM radios
could interfere with plane navigation systems
since they used neighboring radio bands.
And out of caution, they banned
almost all personal electronics on flights.
But airlines could test any device for interference
and overrule the FAA ban to allow it on board.
Any device, that is, except a phone,
because another organization has jurisdiction over phones
and that's the Federal Communications Commission, or FCC.
See a phone on the ground
with buildings and hills around it
can usually only see one or two cell towers
at the same time.
But from the air, it could see 10 or 20 or more.
The concern was that 200 phones
traveling at 800 kilometers per hour in a plane
could rapidly connect to many towers at once,
overloading the infrastructure.
At least that's what the FCC thought could happen.
So, they banned cell phone use in flight in 1991.
(funky music)
But there's a problem with this theory.
A plane is a big metal enclosure,
essentially a Faraday cage.
So, it should block almost all electromagnetic signals.
That's why plane antennas are located on the outside.
Your phone signals can only escape through the windows,
which means they go horizontally out the sides of the plane.
So, they would have to travel long distances
before reaching the ground.
And the cell towers your phone is trying to connect to,
well they are tilted downwards, you know,
to collect all the signals from people
walking around on the ground.
So, it's very hard to make a connection from the air
unless you're flying really low.
So, phones could only conceivably disrupt ground networks
during takeoff or landing.
And the FCC never even tested if this was the case.
In 2005, they went before Congress and said
the rule banning 800 MHz cell phone use in flight
may not be needed in order
to protect ground-based cellular networks.
As far as we know,
a mobile phone has never caused an air accident.
All airplane mode does for sure is save your battery life.
So, why are these rules still around?
- I've been flying myself
and where I've gotten interference,
you know, when you're talking to a traffic control
and you get that (imitating a phone signal),
you know that signal,
and that is because someone is either using their phone
or the phone is on.
Will one phone in an aircraft cause any problems?
Probably not.
Will 200 do something?
Maybe.
Rather than taking the chance of like, let's everyone
update their Twitter profile at 500 feet,
rather than saying that, we're saying no,
you know, just keep them off, you know,
enjoy the Wi-Fi up at altitude and that's it.
- But airplane mode might soon be a thing of the past.
The EU actually no longer requires it
and is pushing for airlines to provide 5G service
on all EU flights.
So, we may eliminate that inconvenience,
but we still have to deal with airplane food.
What do you think about airplane food?
- I only eat the bread rolls.
That's only thing I can handle.
Apart from that, everything tastes like mush.
- It's can be very good. It can be very terrible.
- Eh, bland-ish, different consistency.
- Do you think the food tastes as good in a plane
as it would on the ground?
- No.
- But bad-tasting food might not be all the airlines' fault.
See, the air that's pumped into the cabin altitude
is really dry.
And the Sahara Desert for reference
has an average relative humidity of 25%,
but inside an airplane cabin, it can be as low as 5%.
This can dry out your nasal passages,
hindering your sense of smell and therefore taste.
The lower cabin pressure can also decrease sensations
like the intensity of salt and sugar.
But there is one flavor that appears to be enhanced
in flight.
What do you drink in an airplane?
What's your drink of choice?
- Apple juice.
- Apple juice?
- Yeah.
- Interesting.
- I mean Coke, that's default
- Orange or apple juice.
- Gin and tonic.
- Maybe a Bloody Mary, but...
- You're the first one today.
- Really?
- Yeah.
A German survey of a thousand flyers
found that more than a quarter of them
order tomato juice in flight.
And what's really weird is that 23% of those people
would never drink it on the ground.
And would you drink Bloody Mary,
would that be like a standard drink at the bar
or is it a special plane drink?
- I only have it on planes.
- So, why is everyone ordering tomato juice?
Well, it could be because of the noise.
A 2015 study points to the chorda tympani,
a nerve that carries taste information
from the tongue to the brainstem.
It runs right past the eardrum,
between the tiny sound conducting bones.
So, loud cabin noise might unintentionally stimulate it.
This could produce an audio illusion
that boosts our sense of umami,
the savory taste you find in MSG, soy sauce,
and well, tomatoes.
- I always drink tomato juice and I never knew why.
It just felt like my plane drink.
Or like spicy tomato juice-
- Yeah.
- Like both of those are favorites of mine.
- Yeah.
So, next time you're on a flight,
go for something extra sweet or salty
or maybe try the tomato juice.
I feel like with how much people fly,
our perspective of flying
is still pretty distorted.
So, why is that?
- Yeah.
I know that we talk a lot about accidents and incidents
and we dig into them really, really deep
and people might ask, "Why would you be doing this?
Doesn't that just make people even more afraid of flying?"
But the fact is that this is one of the prime reasons
why aviation is as safe as it is.
The fact that we have hundreds of professionals
that dig deep into these accidents
means that we learn from them.
So, every flight becomes a little bit safer.
That's actually a big reason
that I started my channel Mentour Pilot in the first place
'cause I promise you, the more you know
the safer you'll feel.
(closing music)
- Do you think that climate change increases turbulence?
- Eh, depends on what people think about their opinions.
- Yeah.
- It's been a bit of that in news recently, hasn't there?
- Today, the media tends to prioritize
sensationalized headlines over key details.
Part of why airplane mode is still such a big deal today
is because of the media frenzy it started in the 1960s.
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to look at all sides of the story.
This is why we specifically asked Ground News
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