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Flying Altitude Limit For An Airliner?  
User currently offlineTancrede From Finland, joined May 2006, 245 posts, RR: 0
Posted (7 years 2 months 1 week 6 days 13 hours ago) and read 5249 times:

As I was yesterday evening flying with a Finnair’s E-170 from HEL to CDG, dodging storm fronts at FL360, I was wondering what would be the highest flying altitude an airliner could reach if it had to, due to severe/extreme turbulences or any other specific reasons.
I have been sometime flying at FL390-400 with an A320 but is it the limit?
Of course, I am not talking about the Concorde as it was a special case and is not anymore in active duty.

33 replies: All unread, showing first 25:
 
User currently offlineWestJetForLife From Canada, joined Jun 2005, 814 posts, RR: 1
Reply 1, posted (7 years 2 months 1 week 6 days 13 hours ago) and read 5245 times:

Highest, if I recall, can be anywhere between FL410 and FL430.

Now, the Concorde, before she retired in 2003, flew at FL600, but that was normal operation.

It's all dependant on engines, weight, weather, etc. The max, I think, is FL430 for heavies and planes like the 737 and 757.

If anyone wants to correct or add on, go right ahead.

Nik



I need a drink.
User currently offlinePhilSquares From , joined Dec 1969, posts, RR:
Reply 2, posted (7 years 2 months 1 week 6 days 13 hours ago) and read 5243 times:

The 744 is certified to FL 451. However, you have to be pretty light to get up there. The "normal" altitudes you'd expect to fly at are 310-390 (perhaps 410). The altitude a aircraft can attain varies on several things. First gross weight. If you are too heavy your altitude will be limited by stall margin. This is usually a factor of 1.3. That way you can take some turbulence, maneuver and not worry about stalling the aircraft.

The second issue is temperature. If it's colder than standard air is more dense thus you will get a little higher, if it's warmer than standard, the air is less dense and your altitude will be lower.

Finally, there is the ceiling the aircraft is certified for. As I mentioned the 747/744 are both FL 451, while the 320 I flew years ago was FL 391.

Personally, being up at the top of your altitude trying to maneuver for CBs isn't the most pleasant thing to do. You don't have any margin, you're generally power limited, so any loss of airspeed and you are behind the power curve. I would much rather go a few hundred miles out of the way than try to cross the top of a front. But, that's just my preferences.


User currently offlineSpruit From United Kingdom, joined Oct 2005, 375 posts, RR: 0
Reply 3, posted (7 years 2 months 1 week 6 days 10 hours ago) and read 5212 times:

Didn't the recent TU154M accident involve a pilot trying to overfly a storm front?

If I recall it correctly he got way outside the envelope for the TU154 which caused a flat spin and the death of all on board!

I think I agree with Phil on this one, go around seems like the better option rather than pushing the altitude service ceiling.

Back on topic, does anyone have any personal experience of FL600 in Concorde? Never managed to fly her and now sadly it will only ever be a fantasy, but what was it like up there? Smooth? Turbulent?

Cheers,

Spru!



E=Mc2
User currently offlineCosmicCruiser From United States of America, joined Feb 2005, 2255 posts, RR: 16
Reply 4, posted (7 years 2 months 1 week 6 days 8 hours ago) and read 5177 times:

Quoting PhilSquares (Reply 2):
I would much rather go a few hundred miles out of the way than try to cross the top of a front. But, that's just my preferences.

Not to mention the CB may be building and will "out climb" you anyway. Rarely a good option.


User currently offlineCptSpeaking From United States of America, joined Apr 2006, 639 posts, RR: 1
Reply 5, posted (7 years 2 months 1 week 6 days 6 hours ago) and read 5142 times:

Quoting CosmicCruiser (Reply 4):
Not to mention the CB may be building and will "out climb" you anyway. Rarely a good option.

Also, with CBs that high, there is the possibility of hail being thrown out the top, and that would pretty much ruin your day...best to go around any thunderstorm IMHO

Your CptSpeaking



...and don't call me Shirley!!
User currently offlineBond007 From United States of America, joined Mar 2005, 5401 posts, RR: 8
Reply 6, posted (7 years 2 months 1 week 6 days 5 hours ago) and read 5125 times:

There are quite a few B744, 767, 777, MD11, and even 738 that fly FL 430 in the US. Many of them cargo flights overflying, which presumably have burnt some fuel off by then ... but rarely ever higher than that.

BTW, out of interest, many G5s and Global Express routinely are flying FL 500 nowadays.


Jimbo



I'd rather be on the ground wishing I was in the air, than in the air wishing I was on the ground!
User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 7, posted (7 years 2 months 1 week 6 days 5 hours ago) and read 5124 times:

Evey aircraft's maximum operating altitude is listed in its Type Certification Data Sheet (TCDS). While an aircraft may be able to fly higher, to do so is illegal.

User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 8, posted (7 years 2 months 1 week 6 days 5 hours ago) and read 5107 times:

Quoting Bond007 (Reply 6):
There are quite a few B744, 767, 777, MD11, and even 738 that fly FL 430 in the US. Many of them cargo flights overflying, which presumably have burnt some fuel off by then ... but rarely ever higher than that.

BTW, out of interest, many G5s and Global Express routinely are flying FL 500 nowadays.

The maximum operating altitude for the B744 is 41,500 feet, the 767 and 777 is 43,100 feet, the MD-11 is 42,000 feet and the 378 is 41,000 feet.

The maximum operating altitude for the G5 is 43,000 feet but with mod's can reach 45,000 feet. Only Global Express is certified above 50,000 feet at 51,000.


User currently offlineBond007 From United States of America, joined Mar 2005, 5401 posts, RR: 8
Reply 9, posted (7 years 2 months 1 week 6 days 5 hours ago) and read 5100 times:

Quoting PhilSquares (Reply 2):
The 744 is certified to FL 451

Sounds more likely than ...

Quoting 474218 (Reply 8):
The maximum operating altitude for the B744 is 41,500 feet

Well ... All I can tell you is I can give you a list of Cargolux, BA, Evergreen, Atlas routinely (or fairly) flying FL430.
EVA MD11s fly 430 from ORD to ANC.

G5's are often at FL490 ....

Not sure your data is correct/current.

Jimbo



I'd rather be on the ground wishing I was in the air, than in the air wishing I was on the ground!
User currently offlinePhilSquares From , joined Dec 1969, posts, RR:
Reply 10, posted (7 years 2 months 1 week 6 days 4 hours ago) and read 5072 times:

Quoting 474218 (Reply 8):
The maximum operating altitude for the B744 is 41,500 feet,

Sorry, but it's 45100, not 41500. The classic is also certified for 45100

[Edited 2007-05-22 17:21:32]

User currently offlineTornado82 From , joined Dec 1969, posts, RR:
Reply 11, posted (7 years 2 months 1 week 6 days 3 hours ago) and read 5051 times:

Quoting Bond007 (Reply 6):
and even 738 that fly FL 430 in the US.

FL410.

Quoting 474218 (Reply 8):


The maximum operating altitude for the G5 is 43,000 feet but with mod's can reach 45,000 feet. Only Global Express is certified above 50,000 feet at 51,000.

Not true.

The G500 and G550 are both 51,000 certified. http://www.gulfstream.com/g550/

Some LearJets (45XR specifically.. maybe more) are also 51,000.


User currently offlineBond007 From United States of America, joined Mar 2005, 5401 posts, RR: 8
Reply 12, posted (7 years 2 months 1 week 6 days 3 hours ago) and read 5039 times:

Quoting Tornado82 (Reply 11):
FL410.

Looks like empty B738 Sunwing positioning flights get up to FL430.

SWG9nnn flight numbers.

Winglets increasing max altitude perhaps ??


Jimbo

[Edited 2007-05-22 18:48:08]


I'd rather be on the ground wishing I was in the air, than in the air wishing I was on the ground!
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17003 posts, RR: 67
Reply 13, posted (7 years 2 months 1 week 6 days 1 hour ago) and read 4997 times:

Quoting Bond007 (Reply 12):

Looks like empty B738 Sunwing positioning flights get up to FL430.

Wouldn't the "time to get down to sub-mask altitude" rear its head here? The aircraft needs to descend to an altitude with breathable air within a certain time in case of a decompression. If on a ferry flight, there are no pax to worry about. Cockpit crew masks are much "better" than the yellow plastic cups.

Just a thought. I don't actually know.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlinePhilSquares From , joined Dec 1969, posts, RR:
Reply 14, posted (7 years 2 months 1 week 6 days 1 hour ago) and read 4986 times:

Quoting Starlionblue (Reply 13):
Wouldn't the "time to get down to sub-mask altitude" rear its head here?

I can't talk about the 738 but I can talk about the 747/744. The limit of 45100 is due to the "high dive" used in the rapid decompression. The aircraft can't make it down from any higher altitude. At 45100, it just makes it in the 4 minute limit for certification.


User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 15, posted (7 years 2 months 1 week 6 days 1 hour ago) and read 4962 times:

Quoting PhilSquares (Reply 10):
Sorry, but it's 45100, not 41500. The classic is also certified for 45100

Your correct it is 45,100 I transposed the numbers.

Quoting Tornado82 (Reply 11):
The G500 and G550 are both 51,000 certified. http://www.gulfstream.com/g550/

You are also correct I didn't dig far enough in the TCDS.


User currently offlineElpinDAB From United States of America, joined Apr 2005, 468 posts, RR: 4
Reply 16, posted (7 years 2 months 1 week 6 days ago) and read 4946 times:

Quoting Tornado82 (Reply 11):
Some LearJets (45XR specifically.. maybe more) are also 51,000

Yea, the others I know of that are certified to 510 are the LJ31 (out of production) and the LJ60...the 31 can get up there for sure, but an LJ60 pilot once told me that they struggle to make it much higher than 410, and that 510 is hopeless. The LJ40 is certified for 510 also, but it's pretty much the same thing as the 45.

As far as the biz jets go, I know the Citation X is certified to 510 also, but I'm not sure if it could actually make it there.

Quoting Bond007 (Reply 12):

Winglets increasing max altitude perhaps ??

Maybe not the max certified altitude, but they might allow you to climb a little higher for the given conditions than without winglets. Winglets decrease induced drag, and at high altitudes where indicated airspeeds are slower, you are flying close to the back side of the power curve (where induced drag becomes greater than parasitic drag). So, that decrease in induced drag would theoretically allow you to climb higher.


Does anybody know how high the 787/A350 will be certified for? Seems like it would be a little higher than the current airliners, unless decompression issues interfere.

[Edited 2007-05-22 20:59:57]

User currently offlineTancrede From Finland, joined May 2006, 245 posts, RR: 0
Reply 17, posted (7 years 2 months 1 week 6 days ago) and read 4931 times:

Quoting PhilSquares (Reply 2):
You don't have any margin, you're generally power limited, so any loss of airspeed and you are behind the power curve.

So, it seems that the main problem when flying higher is loss of power and of course of airspeed. I then thought incorrectly that it could be also structural limitation that will restrain the plane to fly in thinner air pressure. Please correct me if I am wrong.


User currently offlineMrocktor From United States of America, joined Jan 2005, 1668 posts, RR: 50
Reply 18, posted (7 years 2 months 1 week 5 days 23 hours ago) and read 4893 times:

Quoting PhilSquares (Reply 14):
The aircraft can't make it down from any higher altitude. At 45100, it just makes it in the 4 minute limit for certification.

The limit is 2 minutes to FL250. Also, above FL410 special conditions apply (which is why current generation airliners don't exceed that altitude much, if at all). The reason the 747 is certified above FL410 is that its certification precedes the relevant ammendment of the FAR and trend in rulemaking.


User currently offlineBond007 From United States of America, joined Mar 2005, 5401 posts, RR: 8
Reply 19, posted (7 years 2 months 1 week 5 days 22 hours ago) and read 4866 times:

Quoting Mrocktor (Reply 18):
Also, above FL410 special conditions apply (which is why current generation airliners don't exceed that altitude much, if at all). The reason the 747 is certified above FL410 is that its certification precedes the relevant ammendment of the FAR and trend in rulemaking.

The "special conditions" are only oxygen requirements right? Either one crewmember must always wear a mask, or have quick-donning masks. These regs start well below FL410 ... FL250/350 depending on number of crewmembers in cockpit, so not a factor here.

Well, and RVSM airspace ends at FL410, so next up is FL430.

747s, 767s, 777s, MD11s must all be certified above FL410.


Jimbo



I'd rather be on the ground wishing I was in the air, than in the air wishing I was on the ground!
User currently offlineDavid L From United Kingdom, joined May 1999, 9524 posts, RR: 42
Reply 20, posted (7 years 2 months 1 week 5 days 20 hours ago) and read 4820 times:

Quoting Spruit (Reply 3):
Didn't the recent TU154M accident involve a pilot trying to overfly a storm front?

I believe so and I don't think it's the only Tu-154 that's fallen foul of such a scenario (and yet some people will still blame the aircraft).

Quoting Spruit (Reply 3):
Back on topic, does anyone have any personal experience of FL600 in Concorde? Never managed to fly her and now sadly it will only ever be a fantasy, but what was it like up there? Smooth? Turbulent?

Not even close - I only managed FL580, four times.  Smile

On one of those flights was there a slight tremor rather than "turbulence". Otherwise, it felt exactly the same as any other jet airliner. I didn't see the ground moving any faster either since, although we were flying twice as fast, we were twice as far away from it. Nor was there any clue whatsoever of breaking the sound barrier, other than the cabin display and the announcement from the flight deck. But that wasn't the point - I just knew and I'd do it again if I could.  Smile


User currently offlineViscount724 From Switzerland, joined Oct 2006, 24922 posts, RR: 22
Reply 21, posted (7 years 2 months 1 week 5 days 17 hours ago) and read 4742 times:

Quoting PhilSquares (Reply 2):
The 744 is certified to FL 451. However, you have to be pretty light to get up there. The "normal" altitudes you'd expect to fly at are 310-390 (perhaps 410).

My recollection of early-model 747s is that the 747SP was the first 747 variant that commonly cruised at FL410 or above. I may be wrong but I recall reading at the time that the SP was approved to operate at up to FL450 and was the first commercial aircraft with that capability. I know that a few of my early SP flights were my first flights above FL390.

Quoting Spruit (Reply 3):
Back on topic, does anyone have any personal experience of FL600 in Concorde? Never managed to fly her and now sadly it will only ever be a fantasy, but what was it like up there? Smooth? Turbulent?

I didn't notice anything unusual at FL560 (or thereabouts) on my one and only Concorde flight in 1989 (at a special $499 BA discount fare for airline employees JFK-LHR). They said it was possible to see the curvature of the earth at that altitude but it wasn't visible to me, and the Concorde's windows were so small it was hard to see very much anyway. It was smooth all the way as I recall. The most notable thing about flying Concorde was how ordinary it all seemed, even at Mach 2. In those days all passengers were also invited to visit the cockpit during the flight.


User currently offlineViscount724 From Switzerland, joined Oct 2006, 24922 posts, RR: 22
Reply 22, posted (7 years 2 months 1 week 5 days 17 hours ago) and read 4743 times:

Quoting PhilSquares (Reply 2):
The 744 is certified to FL 451. However, you have to be pretty light to get up there. The "normal" altitudes you'd expect to fly at are 310-390 (perhaps 410).

My recollection of early-model 747s is that the 747SP was the first 747 variant that commonly cruised at FL410 or above. I may be wrong but I recall reading at the time that the SP was approved to operate at up to FL450 and was the first commercial aircraft with that capability (other than Concorde). I know that a few of my early SP flights were my first flights above FL390.

Quoting Spruit (Reply 3):
Back on topic, does anyone have any personal experience of FL600 in Concorde? Never managed to fly her and now sadly it will only ever be a fantasy, but what was it like up there? Smooth? Turbulent?

I didn't notice anything unusual at FL560 (or thereabouts) on my one and only Concorde flight in 1989 (at a special $499 BA discount fare for airline employees JFK-LHR). They said it was possible to see the curvature of the earth at that altitude but it wasn't visible to me, and the Concorde's windows were so small it was hard to see very much anyway. It was smooth all the way as I recall.

The most notable thing about flying Concorde was how ordinary it all seemed, even at Mach 2. In those days passengers were also invited to visit the cockpit during the flight.

[Edited 2007-05-23 04:26:58]

User currently offlinePhilSquares From , joined Dec 1969, posts, RR:
Reply 23, posted (7 years 2 months 1 week 5 days 15 hours ago) and read 4713 times:

Quoting Tancrede (Reply 17):
So, it seems that the main problem when flying higher is loss of power and of course of airspeed. I then thought incorrectly that it could be also structural limitation that will restrain the plane to fly in thinner air pressure. Please correct me if I am wrong.

Well, it's a combination of a lot of factors. When you're heavy in the 744, 350 Tonnes for example, the FMS will give you a optimum altitude and a max altitude. The max altitude is limited by stall protection at 1.3G. So, it's a thrust issue there. At max altitude, 451, it's a matter of making an emergency descent, that can be done several ways, but you bump up against structural limits, barber pole for example in that case.

Quoting Mrocktor (Reply 18):
The limit is 2 minutes to FL250. Also, above FL410 special conditions apply (which is why current generation airliners don't exceed that altitude much, if at all). The reason the 747 is certified above FL410 is that its certification precedes the relevant ammendment of the FAR and trend in rulemaking.

Sorry to disagree, but the certification is 14,000 in 4 minutes. If you are flying a N reg aircraft then there are special O2 requirements that come into play up that high. However, that requirement is not universal and most countries don't have that restriction.

Quoting Viscount724 (Reply 22):
My recollection of early-model 747s is that the 747SP was the first 747 variant that commonly cruised at FL410 or above. I may be wrong but I recall reading at the time that the SP was approved to operate at up to FL450 and was the first commercial aircraft with that capability (other than Concorde). I know that a few of my early SP flights were my first flights above FL390.

Every 747 has been certified for 451. Now realistically, the old 100's would never see it unless they were empty. A MTOW resulted in an initial cruise of 270-290. At the end of the flight you'd be at 350-370. I have flown the SP and seem to recall going up to perhaps 350-370 on the initial cruise. But, we're talking about substantially less payload too.


User currently offlineDavid L From United Kingdom, joined May 1999, 9524 posts, RR: 42
Reply 24, posted (7 years 2 months 1 week 5 days 7 hours ago) and read 4647 times:

Quoting Viscount724 (Reply 22):
They said it was possible to see the curvature of the earth at that altitude but it wasn't visible to me

Agreed. I have to assume it was noticeable from the cockpit windows, though.

Quoting Viscount724 (Reply 22):
and the Concorde's windows were so small it was hard to see very much anyway.

And that takes us back to one of the factors involved in certifying maximum altitude - the ability to maintain some cabin pressure if a window blows out (or maybe two?). Concorde's windows were so small because of the greater pressure differential at cruise altitude.


25 Post contains links Mrocktor : FAR 25.841(a)(2)(i)
26 PhilSquares : We're talking two different issues. The certification is based on the aircraft's ability to descend from it's maximum altitude to 14,000 in 4 minutes
27 Bond007 : This has nothing to do with time to descend ... but a max of 2 minutes exposure allowed at 25,000ft. Yes, this is interesting, since it is based upon
28 PhilSquares : There is where things get a little sticky. Most cargo operators, like NW and FX operate under 121. Airlines don't have to operate positioning flights
29 Bond007 : Agreed, but I'm guessing that those other 747s I listed at FL430 like Cargolux, EVA, Atlas probably don't though. But it does appear from Part 121, t
30 Mrocktor : Fair enough. Fact remains that if you want to certify an airliner to fly above FL250, you have to prove it is capable of a descent to that level at s
31 PhilSquares : The 777 is certified to FL 431, this certainly above your FL 410, the 744 is 451, again above your FL 410, even the 340 is certified to FL 41450, whi
32 Mrocktor : Here it is, in the clearest way I can state it: (1) There is a requirement that cabin altitude never exceed 40,000ft. (2) There is a requirement that
33 Blackbird : What O2 requirements come into effect at high-altitude Andrea Kent
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