[sean.patrick926]

Hey there, long time listener first time caller. I was just going over the Wiki page and found the question that has to do with commercial aviation altitude. It stated:

"It is widely stated you would need to be at a height of at least 40,000 ft to get even a hint of curvature if earth were round. Commercial aircraft are not allowed to fly this high. They are only allowed to fly just under this altitude. 36,000ft might be typical."

The information regarding the altitude is wrong. Depending on aircraft, commercial flights are often above FL400 (40,000ft), topping out around FL450. Some smaller business aircraft can reach altitudes up to FL510, and military aircraft even higher. I personally have flown a B737 up to FL410 (but could not discern any curvature at that altitude). Is there an option on the site to initiate a change of that information? Thanks.

[TomInAustin]

Hey there, long time listener first time caller. I was just going over the Wiki page and found the question that has to do with commercial aviation altitude. It stated:

"It is widely stated you would need to be at a height of at least 40,000 ft to get even a hint of curvature if earth were round. Commercial aircraft are not allowed to fly this high. They are only allowed to fly just under this altitude. 36,000ft might be typical."

The information regarding the altitude is wrong. Depending on aircraft, commercial flights are often above FL400 (40,000ft), topping out around FL450. Some smaller business aircraft can reach altitudes up to FL510, and military aircraft even higher. I personally have flown a B737 up to FL410 (but could not discern any curvature at that altitude). Is there an option on the site to initiate a change of that information? Thanks.

That has been pointed out many times.   No change

[Pete Svarrior]

That has been pointed out many times. No change

Indeed. As this is repeatedly presented with no evidence, there is no grounds for editing the article. The typical cruising altitude for the 737, the most common airliner today, is 36,000ft. The 747 cruises slightly higher than that. The "I went on a flight and totally saw curvature!" claim is a non-starter.

It's quite believable that the figures have grown inaccurate over the last 15 years, and if anything the minimum height from which you should expect to see a curve should be considerably increased, but one has to ask two questions:

• What should the new figures be, and why?
• Does this actually affect the merit of the argument being made in the FAQ? (It doesn't)

[sean.patrick926]

1. What should the new figures be, and why?
2. Does this actually affect the merit of the argument being made in the FAQ? (It doesn't)

1. The new figures should reflect accuracy on the part of current cruising altitudes for commercial airliners. While a 'typical' cruising altitude might be 36,000ft, as I said previously, commercial aircraft can and do cruise at altitudes of up to 45,000ft, depending on the airframe. The Concorde (obviously no longer in service) reached up to 60,000ft.
2. It affects the merit of the argument being made only in that the "hint" of curvature (in my experience) cannot be seen at 40,000ft. According to pilots of high altitude military aircraft, namely the U-2 and SR-71, curvature is visible upwards of 60,000ft.

[Pete Svarrior]

According to pilots of high altitude military aircraft, namely the U-2 and SR-71, curvature is visible upwards of 60,000ft.

Anecdotally. But yes, that's the figure I can immediately see would be worthwhile correcting.

[TomInAustin]

That has been pointed out many times. No change

Indeed. As this is repeatedly presented with no evidence, there is no grounds for editing the article. The typical cruising altitude for the 737, the most common airliner today, is 36,000ft. The 747 cruises slightly higher than that. The "I went on a flight and totally saw curvature!" claim is a non-starter.

It's quite believable that the figures have grown inaccurate over the last 15 years, and if anything the minimum height from which you should expect to see a curve should be considerably increased, but one has to ask two questions:

• What should the new figures be, and why?
• Does this actually affect the merit of the argument being made in the FAQ? (It doesn't)

The point is that "not allowed to" is the incorrect part.   Not the curve of the earth or the average 737 altitude. 

[Pete Svarrior]

The point is that "not allowed to" is the incorrect part.

Could you elaborate? Commercial aircraft do have a maximum cruising altitude which they're not allowed to exceed. That's common practice in any engineering, equipment is rated to operate under certain conditions and must not be used outside of it.

[TomInAustin]

The point is that "not allowed to" is the incorrect part.

Could you elaborate? Commercial aircraft do have a maximum cruising altitude which they're not allowed to exceed. That's common practice in any engineering, equipment is rated to operate under certain conditions and must not be used outside of it.

Yes, all aircraft have service ceilings.   The Wiki/FAQ makes it sound like the law does not allow commercial aircraft to exceed 35,000 feet.

Example : 787 Dreamliner 43,000'

[Pete Svarrior]

The Wiki/FAQ makes it sound like the law does not allow commercial aircraft to exceed 35,000 feet.

Does it? Where did you get that from? Even the figure for a typical cruising altitude in the FAQ is higher than what you allege is "not allowed by law". It sounds to me like you're interpreting what's been written to mean what you want it to mean.

[TomInAustin]

The Wiki/FAQ makes it sound like the law does not allow commercial aircraft to exceed 35,000 feet.

Does it? Where did you get that from? Even the figure for a typical cruising altitude in the FAQ is higher than what you allege is "not allowed by law". It sounds to me like you're interpreting what's been written to mean what you want it to mean.

Well, how about here?

"Quite simply you cannot. It is widely stated you would need to be at a height of at least 40,000 ft to get even a hint of curvature if earth were round. Commercial aircraft are not allowed to fly this high. They are only allowed to fly just under this altitude. 36,000ft might be typical. In addition, the windows on commercial aircraft are small and heavily curved. Even if they flew high enough for a person to see curvature, it would still not be visible to passengers."

How else could one interpret "Commercial aircraft are not allowed to fly this high"?

It sounds to me like you are either ignoring what you don't want to hear or you don't know what is in the FAQ.

In any case, the information is wrong per the OP.

[Pete Svarrior]

How else could one interpret "Commercial aircraft are not allowed to fly this high"?

I already told you. Commercial aircraft can't exceed the altitude they've been certified to safely cruise at, despite the fact that they're likely physically capable of doing so.

In any case, the information is wrong per the OP.

I already addressed that. It's not wrong. The numbers might be slightly outdated or needlessly conservative, and might benefit from adjusting. I reached out for suggestions on how to correct them, but you said they aren't what needs correcting.

If you are now once again of the opinion that the numbers need adjusting, please could you respond to my questions, as posed in my first response?

[TomInAustin]

How else could one interpret "Commercial aircraft are not allowed to fly this high"?

I already told you. Commercial aircraft can't exceed the altitude they've been certified to safely cruise at, despite the fact that they're likely physically capable of doing so.

I have already agreed with you that all aircraft have a service ceiling but that is not  is not what it says in the FAQ

In any case, the information is wrong per the OP.

I already addressed that. It's not wrong. The numbers might be slightly outdated or needlessly conservative, and might benefit from adjusting. I reached out for suggestions on how to correct them, but you said they aren't what needs correcting.

If you are now once again of the opinion that the numbers need adjusting, please could you respond to my questions, as posed in my first response?

Without looking up the service ceiling of every commercial plane I have no answer.  But a 737-800, one of the most common airliners in service has a ceiling of 41k feet.   In the USA a commercial airplane operates under Part 135 and almost any plane can be operated under that rule.  One of the highest-flying active aircraft is the Cessna Citation X with a ceiling of 51k and is commonly flown under Part 135.

The point if all this is that the wording in the FAQ suggests that planes are limited to 36k (by regulation or law or some other unknown reason) and that is not correct.  The author's meaning is lost if that was not the intent.


As for being outdated...

"When Boeing introduced the 747-100 in 1969, its maximum ceiling was 45,100 feet; half a century later, when Boeing introduced the 777x, its maximum ceiling was 43,100 feet."

Cruising altitudes are more about fuel efficiency and smooth air than any other factors.

[TomInAustin]

That has been pointed out many times. No change

Indeed. As this is repeatedly presented with no evidence, there is no grounds for editing the article. The typical cruising altitude for the 737, the most common airliner today, is 36,000ft. The 747 cruises slightly higher than that. The "I went on a flight and totally saw curvature!" claim is a non-starter.

It's quite believable that the figures have grown inaccurate over the last 15 years, and if anything the minimum height from which you should expect to see a curve should be considerably increased, but one has to ask two questions:

• What should the new figures be, and why?
• Does this actually affect the merit of the argument being made in the FAQ? (It doesn't)

I totally agree with the fact that an airliner doesn't fly high enough to see curvature.   I have flown from Austin to Heathrow and back on a 787 and there was no curvature visible. (Of course, that invalidates the argument that airline windows make the horizon look like curvature).  The ceiling is 43k' but that, of course, does not mean we were flying at 43k.

There is a massive amount of anecdotal evidence from people flying Concord and some business jets that fly over 50k that curvature is visible.

[Tumeni]

There is a massive amount of anecdotal evidence from people flying Concord and some business jets that fly over 50k that curvature is visible.

... not forgetting those who have taken the thrill rides in the Russian MIG aircraft;

https://migflug.com/flights-prices/mig-29-edge-of-space/

[TomInAustin]

There is a massive amount of anecdotal evidence from people flying Concord and some business jets that fly over 50k that curvature is visible.

... not forgetting those who have taken the thrill rides in the Russian MIG aircraft;

https://migflug.com/flights-prices/mig-29-edge-of-space/

Or the people that have been to space and sent back pics

[Pete Svarrior]

I have already agreed with you that all aircraft have a service ceiling but that is not  is not what it says in the FAQ

It is. Sorry. You probably honestly misinterpreted the wording, but it's been explained to you. Now you're manufacturing outrage. Perhaps that's why your precious attempts at having the FAQ modified were unsuccessful. Let's try and help you with that. If you think the phrasing can be improved upon, make a suggestion and justify it. But don't tell us "nuh uh when you said that thing you didn't mean what you're telling me you did, I know best" - it doesn't inspire serious treatment.

As for being outdated...

[other planes existed in the past]

Yes. The FAQ explicitly states that these figure apply to most common commercial aircraft. This appears to still be true, but I'm willing to entertain the thought that you have better information.

Of fucking course other planes exist, and that they're crafted to different specs. Of fucking course those existed in the past. How does that help, in any way, shape or form, with the uncontroversial issue of people who claim to have seen the curvature from a position where they're physically unable to see it? How does it affect claims about the most common case?

Focus. You said you wanted to fix the FAQ. Go for it. Don't ramble about how you can misinterpret the wording if you really want to. Provide constructive suggestions.

[TomInAustin]

I have already agreed with you that all aircraft have a service ceiling but that is not  is not what it says in the FAQ

It is. Sorry. You probably honestly misinterpreted the wording, but it's been explained to you. Now you're manufacturing outrage. Perhaps that's why your precious attempts at having the FAQ modified were unsuccessful. Let's try and help you with that. If you think the phrasing can be improved upon, make a suggestion and justify it. But don't tell us "nuh uh when you said that thing you didn't mean what you're telling me you did, I know best" - it doesn't inspire serious treatment.

As for being outdated...

[other planes existed in the past]

Yes. The FAQ explicitly states that these figure apply to most common commercial aircraft. This appears to still be true, but I'm willing to entertain the thought that you have better information.

Of fucking course other planes exist, and that they're crafted to different specs. Of fucking course those existed in the past. How does that help, in any way, shape or form, with the uncontroversial issue of people who claim to have seen the curvature from a position where they're physically unable to see it? How does it affect claims about the most common case?

Focus. You said you wanted to fix the FAQ. Go for it. Don't ramble about how you can misinterpret the wording if you really want to. Provide constructive suggestions.

Ok for fuck's sake Pete.  You know as well as I do if someone reads that something is not allowed that 99 out of 100 are going to interpret it to mean it is not allowed. Why is that so hard?   And I never said you could see the curvature, I said that the FAQ is wrong about allowed altitudes.  Get a grip.


If I was going to edit it I would say that most commercial aircraft fly below 45,000 feet.  That is a true statement and not open to some nebulous interpretation.

Asian girls can get so moody.

[Pete Svarrior]

Ok for fuck's sake Pete.  You know as well as I do if someone reads that something is not allowed that 99 out of 100 are going to interpret it to mean it is not allowed. Why is that so hard?

Sorry, I simply disagree. Your interpretation is relatively unique. In over a decade of that phrase being left as-is, you're the only person I'm aware of that was confused by this sentence. And I'm sure you've noticed that we have some particularly picky people around here when it comes to phrasing. Could it be that someone read it that way before? Sure. But it'll be a far cry from your 99%

And I never said you could see the curvature

At no point did I suggest that you said that. What I said was that your comments are not helping to improve the question within its stated goal - which is correcting a common misconception. What I'm saying is that you're losing your focus too easily. You set out to improve a Q&A, but now you're arguing that you know the meaning behind the words we wrote better than we do, or accusing us of making it deliberately ambiguous. Surely you can see how this approach is not helping?

If I was going to edit it I would say that most commercial aircraft fly below 45,000 feet.  That is a true statement and not open to some nebulous interpretation.

There you go! A suggestion! I'll look into it, but I'd like to make sure we find a figure that won't require an edit in the foreseeable future. Otherwise, someone will inevitably accuse us of flip-flopping. You know how RE'ers are

Asian girls can get so moody.

I'm just being tsundere with you.

[ChrisTP]

Sorry, I simply disagree. Your interpretation is relatively unique. In over a decade of that phrase being left as-is, you're the only person I'm aware of that was confused by this sentence.

I disagree with your disagreement. It's very easy to misinterpret (or take it literally which apparently we aren't supposed to), when I first read it I also took it to mean the same thing as the OP but I just went looking around the interwebs for more information on the subject and found all the information I needed. I didn't bother to mention it here because the whole FE wiki is somewhat a lost cause for confirmed facts and more of a collection of flat earth related stuff that people think or theorise, which is what I assumed you were going for... a library or index of FE information (or misinformation depending on who you ask). Judging from this whole thread I'm kinda glad I didn't bother to mention it because it seems something so basic gets contested to death It's not a hard concept to grasp that saying something is not allowed when it actually is allowed is incorrect.

But hey what do I know I'm just one of those pesky roundheads!

[Dr David Thork]

Ok, lets put some actual facts into this.

So in 1982 they changed the rules on how close aircraft could be to each other. So instead of stacking them every 2000 feet, they could now stack them every 1000 feet. This was done for altitudes between FL290 and FL410. It was called RVSM. Reduced Vertical Separation Minima.
https://www.skybrary.aero/index.php/Reduced_Vertical_Separation_Minima_(RVSM)

This is important. There is no FL420. The next one from FL410 is FL430. Now we are back to 2000ft jumps, not 1000ft. Its a big stretch.


So

Muh Boeing 747-100 in 1969, its maximum ceiling was 45,100 feet

is a moot point. Air traffic control aren't going to give you a FL430.

Why not, like what the hell is with 41,000ft? Well it is mostly a kind of legacy hard ceiling myth legend type thing.
https://books.google.co.uk/books?id=-7gvtZkKKP4C&pg=PA17&lpg=PA17&dq=highest+flight+level+you+have+ever+received?&source=bl&ots=U7vUMzBnMB&sig=ACfU3U1naog-MFxu9pJ4JFmr_yRP4FQNOw&hl=en&sa=X&ved=2ahUKEwj4yNXxxPzlAhWSRMAKHf_hAqQ4KBDoATAEegQIExAB#v=onepage&q=highest%20flight%20level%20you%20have%20ever%20received%3F&f=false

The same wisdom prevails today. The air traffic guy isn't going to even dream of giving you something over 41,000ft. Its not even going to cross his mind. Those altitudes are for the military and rich pricks flying private jets that high purely because they can and want to let everyone on the radio know they have lots of money. And he's going to give the jet FL390 and they'll ask for FL510 and he's going to roll his eyes and say fine. 

And even if your airliner has a service ceiling of 45,000ft, you're not going to be given FL450. You aren't even going to be given FL410. You might get offered FL410 a handful of times in a 30 year career (usually only possible when you are re-positioning the aircraft and its pretty empty). You'll tell your mates you got offered it. You'll remember the flight. You'll sit gawping at the altimeter as it slowly clicks up and you'll probably make a little announcement for the passengers if you have any to let them know that they should probably buy a lottery ticket this week.

commercial aircraft can and do cruise at altitudes of up to 45,000ft

So this is bullshit.

A service ceiling isn't the same as the flight levels you fly. I just checked aircraft in Europe right now. Of 604 airline aircraft I can see, not one single one of them is at FL410 or above. https://www.flightradar24.com/51.54,-0.67/5