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Topic: Flying Altitude Limit For An Airliner?
Username: Tancrede
Posted 2007-05-22 07:48:46 and read 5724 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.

Topic: RE: Flying Altitude Limit For An Airliner?
Username: WestJetForLife
Posted 2007-05-22 08:09:21 and read 5720 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

Topic: RE: Flying Altitude Limit For An Airliner?
Username: PhilSquares
Posted 2007-05-22 08:23:15 and read 5718 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.

Topic: RE: Flying Altitude Limit For An Airliner?
Username: Spruit
Posted 2007-05-22 10:40:09 and read 5687 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!

Topic: RE: Flying Altitude Limit For An Airliner?
Username: CosmicCruiser
Posted 2007-05-22 13:17:38 and read 5652 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.

Topic: RE: Flying Altitude Limit For An Airliner?
Username: CptSpeaking
Posted 2007-05-22 15:12:20 and read 5617 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

Topic: RE: Flying Altitude Limit For An Airliner?
Username: Bond007
Posted 2007-05-22 15:56:35 and read 5600 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

Topic: RE: Flying Altitude Limit For An Airliner?
Username: 474218
Posted 2007-05-22 16:02:43 and read 5599 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.

Topic: RE: Flying Altitude Limit For An Airliner?
Username: 474218
Posted 2007-05-22 16:24:53 and read 5582 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.

Topic: RE: Flying Altitude Limit For An Airliner?
Username: Bond007
Posted 2007-05-22 16:35:45 and read 5575 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

Topic: RE: Flying Altitude Limit For An Airliner?
Username: PhilSquares
Posted 2007-05-22 17:20:27 and read 5547 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]

Topic: RE: Flying Altitude Limit For An Airliner?
Username: Tornado82
Posted 2007-05-22 18:03:26 and read 5526 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.

Topic: RE: Flying Altitude Limit For An Airliner?
Username: Bond007
Posted 2007-05-22 18:23:09 and read 5514 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]

Topic: RE: Flying Altitude Limit For An Airliner?
Username: Starlionblue
Posted 2007-05-22 19:43:46 and read 5472 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.

Topic: RE: Flying Altitude Limit For An Airliner?
Username: PhilSquares
Posted 2007-05-22 19:56:02 and read 5461 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.

Topic: RE: Flying Altitude Limit For An Airliner?
Username: 474218
Posted 2007-05-22 20:27:46 and read 5437 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.

Topic: RE: Flying Altitude Limit For An Airliner?
Username: ElpinDAB
Posted 2007-05-22 20:49:08 and read 5421 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]

Topic: RE: Flying Altitude Limit For An Airliner?
Username: Tancrede
Posted 2007-05-22 21:05:03 and read 5406 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.

Topic: RE: Flying Altitude Limit For An Airliner?
Username: Mrocktor
Posted 2007-05-22 22:05:09 and read 5368 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.

Topic: RE: Flying Altitude Limit For An Airliner?
Username: Bond007
Posted 2007-05-22 23:01:41 and read 5341 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

Topic: RE: Flying Altitude Limit For An Airliner?
Username: David L
Posted 2007-05-23 00:43:26 and read 5295 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

Topic: RE: Flying Altitude Limit For An Airliner?
Username: Viscount724
Posted 2007-05-23 04:23:30 and read 5217 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.

Topic: RE: Flying Altitude Limit For An Airliner?
Username: Viscount724
Posted 2007-05-23 04:25:23 and read 5218 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]

Topic: RE: Flying Altitude Limit For An Airliner?
Username: PhilSquares
Posted 2007-05-23 06:32:55 and read 5188 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.

Topic: RE: Flying Altitude Limit For An Airliner?
Username: David L
Posted 2007-05-23 13:50:33 and read 5122 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.

Topic: RE: Flying Altitude Limit For An Airliner?
Username: Mrocktor
Posted 2007-05-23 15:39:36 and read 5101 times.

Quoting PhilSquares (Reply 23):
Sorry to disagree, but the certification is 14,000 in 4 minutes

FAR 25.841(a)(2)(i)

Topic: RE: Flying Altitude Limit For An Airliner?
Username: PhilSquares
Posted 2007-05-23 16:08:45 and read 5107 times.

Quoting Mrocktor (Reply 25):
Quoting PhilSquares (Reply 23):
Sorry to disagree, but the certification is 14,000 in 4 minutes

FAR 25.841(a)(2)(i)

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 or less. IIRC the issue is contained in 121.333. The 747/744 are certificated with that restriction in mind. Perhaps certification was a poor choice of words on my part.

Topic: RE: Flying Altitude Limit For An Airliner?
Username: Bond007
Posted 2007-05-23 17:42:51 and read 5095 times.

Quoting Mrocktor (Reply 25):
FAR 25.841(a)(2)(i)

This has nothing to do with time to descend ... but a max of 2 minutes exposure allowed at 25,000ft.

Quoting PhilSquares (Reply 26):
IIRC the issue is contained in 121.333.

Yes, this is interesting, since it is based upon the amount of supplemental oxygen available to a percentage of the pax, if the aircraft can or cannot descend to 14,000 in 4 minutes or less.

It would appear that if the flight does not have any pax (cargo) and/or not Part 121, then as long as the crew have enough oxygen, the regulation does either not apply, or does not restrict you from flying as high as you like. So, in the example of the positioning flights flying at FL430, even if they are flying Part 121, it doesn't matter if they cannot descend to 14,000ft in 4 mins, as long as the crew have enough oxygen to satisfy the requirements (there are no pax to supply oxygen to).


Jimbo

Topic: RE: Flying Altitude Limit For An Airliner?
Username: PhilSquares
Posted 2007-05-23 18:09:46 and read 5087 times.

Quoting Bond007 (Reply 27):
It would appear that if the flight does not have any pax (cargo) and/or not Part 121, then as long as the crew have enough oxygen, the regulation does either not apply, or does not restrict you from flying as high as you like. So, in the example of the positioning flights flying at FL430, even if they are flying Part 121, it doesn't matter if they cannot descend to 14,000ft in 4 mins, as long as the crew have enough oxygen to satisfy the requirements (there are no pax to supply oxygen to).

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 under 121, and may do so under 91. However, should anything happen, since 121 is more restrictive (generally) than 91, there might be a little 20/20 hindsight in the operation. I know when I worked for a 121 carrier, we generally ferried under 121 unless it was an engine out ferry. Then it was under 91, but our procedures for the engine out ferry were very restrictive, much more so than 121, for example, daylight only, no wet runways.

Topic: RE: Flying Altitude Limit For An Airliner?
Username: Bond007
Posted 2007-05-23 19:07:01 and read 5069 times.

Quoting PhilSquares (Reply 28):
Most cargo operators, like NW and FX operate under 121.

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, that you don't have to necessarily be able to descend to 14,000 in 4 minutes, but if you can't you must have enough oxygen ... which if you are cargo, or positioning, oxygen supply is not an issue for only the crew.


Jimbo

Topic: RE: Flying Altitude Limit For An Airliner?
Username: Mrocktor
Posted 2007-05-23 19:24:25 and read 5057 times.

Quoting PhilSquares (Reply 26):
We're talking two different issues.

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 such a rate that cabin altitude does not exceed 25,000ft for more than 2 minutes. Unless you can prove that sudden decompression is extremely improbable (which with wing mounted engines, you can't), that pretty much translates to a 2 minute descent to 25,000ft.

Likewise, due to item (2)(ii) of the same FAR, you have to demonstrate you can get below FL400 before the cabin altitude exceeds 40,000ft. This is why we see planes currently be certified to 41,000ft, but not above. It is common practice for the authorities to accept that the aircraft is capable of descending those 1000ft in time, more than that requires considerable evidence.

Note that all the recent aircraft certified above 41,000ft (the Gulfstreams up to 51,000, for instance) are planes with rear mounted engines. This means that the "critical hole" in the pressure vessel (which is used to calculate decompression time) does not have to be the size of the largest fragment model for rotor burst, as would be the case if the engines were wing mounted and therefore could release fragments towards the pressure vessel. This means they can use much lower dedecompression rates in the calculation, meaning the plane has that much more time to descend and meet the time requirements (cabin never above 40,000, no more than 2 minutes above 25,000).

Quoting Bond007 (Reply 27):
This has nothing to do with time to descend ... but a max of 2 minutes exposure allowed at 25,000ft.

Yes, it is a requirement on exposure not the aircraft's altitude. It is intimately related to the time to descend though, specially if potential sources of sudden decompression exist.

Topic: RE: Flying Altitude Limit For An Airliner?
Username: PhilSquares
Posted 2007-05-23 20:19:10 and read 5041 times.

Quoting Mrocktor (Reply 30):
This is why we see planes currently be certified to 41,000ft, but not above.

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, while the recently certified 380 is good to FL 430. So, I am not sure where you're coming from when you make your statement about FL 410.

Reading your reference about CFR25.841 Pressurized cabins doesn't prove your point either. It says the max cabin altitude is 8000 feet (Maximum), 2) The airplane must be designed so that occupants will not be exposed to a cabin pressure altitude that exceeds the following after decompression from any failure condition not shown to be extremely improbable:

(i) Twenty-five thousand (25,000) feet for more than 2 minutes; or

(ii) Forty thousand (40,000) feet for any duration.

(3) Fuselage structure, engine and system failures are to be considered in evaluating the cabin decompression.

and it continues on to state all the controls and indicators that must be in the pressurization system.

So, I would argue, the aircraft manufactures look mainly at cabin integrity, doors and windows. They do a failure analysis and can prove their point that the two conditions 40,000 and 25,000 would statistically never happen.

However, 121.333 goes further and mandates the "high dive" to be accomplished in 4 minutes or less and to FL 140.

I guess I just don't get the point(s) you're trying to make.

Topic: RE: Flying Altitude Limit For An Airliner?
Username: Mrocktor
Posted 2007-05-24 20:26:26 and read 4896 times.

Quoting PhilSquares (Reply 31):
I guess I just don't get the point(s) you're trying to make

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 cabin altitude not exceed 25,000ft for more than 2 minutes.

(3) Sudden decompression, such as that caused by a third of your engine's fan plowing through the cabin, tends to make pressure equalize pretty quickly.

(4) It is difficult to meet requirement (1) when you are flying much higher than 40,000ft

(5) It is difficult to meet requirement (2) if you can't demonstrate descent from your highest cruise altitude to 25,000 ft in ~2 minutes

Thats it, really.

Incidentally, airliners with huge cabin volumes relative to the size of their engines (A380, for instance) have it easier, since it takes more time for pressure to equalize. Maybe that is how they managed to certify it up to FL430.

Topic: RE: Flying Altitude Limit For An Airliner?
Username: Blackbird
Posted 2007-05-25 01:47:15 and read 4814 times.

What O2 requirements come into effect at high-altitude

Andrea Kent


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