Max Service ceiling for commercial airplanes

Out of curiosity I was wondering which civilian passenger airplanes
have the highest service ceilings? Wikipedia indicates that some
business jets have ceilings greater than 53000 ft or so while the 747
has only 43000 ft. Also why do large aircraft fly much lower than
their service ceilings? Usually I never see a large jet go beyond
37000 or so even on very long haul flights. I assume they would be
even more efficient if they flew close to service ceilings on long
haul flights.

On Jan 29, 6:03*pm, wrote:
Out of curiosity I was wondering which civilian passenger airplanes
have the highest service ceilings? Wikipedia indicates that some
business jets have ceilings greater than 53000 ft or so while the 747
has only 43000 ft. Also why do large aircraft fly much lower than
their service ceilings? Usually I never see a large jet go beyond
37000 or so even on very long haul flights. I assume they would be
even more efficient if they flew close to service ceilings on long
haul flights.

Just guessing, but perhaps the smaller cabin size handles the larger
differential pressure reqiuired better than a big cabin. The extra
expense (and weight) to reinforce a large cabin (ie. heavy jet size)
may not be worth it.

I've been on commercial flights up to FL410, and (I beleive) FL430.
These were long-haul international flights.

--Dan

On Jan 30, 2:03*pm, wrote:
Out of curiosity I was wondering which civilian passenger airplanes
have the highest service ceilings? Wikipedia indicates that some
business jets have ceilings greater than 53000 ft or so while the 747
has only 43000 ft. Also why do large aircraft fly much lower than
their service ceilings? Usually I never see a large jet go beyond
37000 or so even on very long haul flights. I assume they would be
even more efficient if they flew close to service ceilings on long
haul flights.

Could be due to weight? When you fly across the Pacific the plane can
only get higher as fuel is burned.

Cheers

On Jan 30, 8:41 am, WingFlaps wrote:
On Jan 30, 2:03 pm, wrote:

Out of curiosity I was wondering which civilian passenger airplanes
have the highest service ceilings? Wikipedia indicates that some
business jets have ceilings greater than 53000 ft or so while the 747
has only 43000 ft. Also why do large aircraft fly much lower than
their service ceilings? Usually I never see a large jet go beyond
37000 or so even on very long haul flights. I assume they would be
even more efficient if they flew close to service ceilings on long
haul flights.

Could be due to weight? When you fly across the Pacific the plane can
only get higher as fuel is burned.


Get higher? I thought that's what the continual small adjustments
effected by the trim wheels do to preclude, especially with the
AutoPilot engaged?

Ramapriya

wrote:
Out of curiosity I was wondering which civilian passenger airplanes
have the highest service ceilings? Wikipedia indicates that some
business jets have ceilings greater than 53000 ft or so while the 747
has only 43000 ft. Also why do large aircraft fly much lower than
their service ceilings? Usually I never see a large jet go beyond
37000 or so even on very long haul flights. I assume they would be
even more efficient if they flew close to service ceilings on long
haul flights.


Weight is a consideration. Even when riding along in Lears, we started
off in the mid 30's. As we burned off fuel, we could efficiently climb,
in stages.. and our final cruising altitude was around 43-45,000 feet.

My PIC told me that if he tried to push the climb any harder, he simply
burned fuel at a faster rate with a poor return on the investment. I was
cabin crew, not front office, but it was still a kick listening to the
airliners trading bumpy ride reports in the FL 300's and we chime in
with smooth rides in the FL400's.. knowing they wont be able to get there.

I'm sure cabin differential is a factor as well. Higher pressurization
differentials require a more robust pressure vessel, which weighs more.
Its a trade-off at the design stage. Flying too high would raise the
cabin altitude too high, despite pressurization, and require oxygen for
the crew and or cabin.

just my 2 cents
Dave

wrote in news:c3217254-afdf-40c0-b87a-
:

Out of curiosity I was wondering which civilian passenger airplanes
have the highest service ceilings? Wikipedia indicates that some
business jets have ceilings greater than 53000 ft or so while the 747
has only 43000 ft. Also why do large aircraft fly much lower than
their service ceilings? Usually I never see a large jet go beyond
37000 or so even on very long haul flights. I assume they would be
even more efficient if they flew close to service ceilings on long
haul flights.


AFAIK the new Bus has one of F430 as well. You can fly right up to the
service ceiling but the max allowable FL goes down with weight. THe buffet
margins become tighter when you are heavy and the max allowable altitude
goes down accordingly,. As you burn fuel you can go up in steps, so on a
long trip you might originally be limited to say, FL330 and then after an
hour or two your limit may rise enough that you can get to 350 and then
again to 370 and so on until you either get to max or its time to come
down. The performance computer (integrated into the FMS) gives you a
constant readout of the limit.
Also, it's not so clever to go up another 4,000 feet if you're going to
have another 100 knots on your nose! A typical rule of thumb tradeoff for
wind/altitude is about 7knots per 1,000 feet, though this isn't hard and
fast.We have tables for it or you can put some projected winds into the FMS
and ask the computer to do it for you.
Another factor is the distance travelled. It makes no sense to go to 410 on
a 200 mile trip. Having said that, the ideal fuel burn profile is close to
straight up and straight down on short trips. No level cruise. IOW, you
keep climbing until you intercept the descent profile and then come down.


Bertie

Dan wrote in news:de91fd98-be3f-4ccb-bef2-79e2ec0dc076
@s13g2000prd.googlegroups.com:

On Jan 29, 6:03*pm, wrote:
Out of curiosity I was wondering which civilian passenger airplanes
have the highest service ceilings? Wikipedia indicates that some
business jets have ceilings greater than 53000 ft or so while the 747
has only 43000 ft. Also why do large aircraft fly much lower than
their service ceilings? Usually I never see a large jet go beyond
37000 or so even on very long haul flights. I assume they would be
even more efficient if they flew close to service ceilings on long
haul flights.

Just guessing, but perhaps the smaller cabin size handles the larger
differential pressure reqiuired better than a big cabin. The extra
expense (and weight) to reinforce a large cabin (ie. heavy jet size)
may not be worth it.

Nah, the reason the little ones can go so high is cause nobody minds if
they do!
They're not constrained by revenue considerations and can have fighter jet
type wings and other shapes to allow good buffet margins up there. You
couldn't get a 747 up that high without buffeting it out of the sky unless
it were empty and out of gas!
The pressurisation wouldn't be able for 510 in a 747 because they woulnd't
make it any tougher than they needed to.
I can't see anyone allowing a pax airplane up above 430 anytime soon for
the simple reason a rapid blowout would kill a hefty percentage of the
people on board.
Even 430 isn't going to be pretty. Anything above 350, in fact, is going to
hurt some people pretty bad.
Until a manufacturer comes up with a technology that ensures a greater
margin of safety above 430 you won't see an airliner certified above that.


Bertie

D Ramapriya wrote in news:2ff47125-cffd-4909-b028-
:

On Jan 30, 8:41 am, WingFlaps wrote:
On Jan 30, 2:03 pm, wrote:

Out of curiosity I was wondering which civilian passenger airplanes
have the highest service ceilings? Wikipedia indicates that some
business jets have ceilings greater than 53000 ft or so while the 747
has only 43000 ft. Also why do large aircraft fly much lower than
their service ceilings? Usually I never see a large jet go beyond
37000 or so even on very long haul flights. I assume they would be
even more efficient if they flew close to service ceilings on long
haul flights.

Could be due to weight? When you fly across the Pacific the plane can
only get higher as fuel is burned.


Get higher? I thought that's what the continual small adjustments
effected by the trim wheels do to preclude, especially with the
AutoPilot engaged?


Huh?


Bertie

On Jan 30, 2:08 pm, Bertie the Bunyip wrote:
D Ramapriya wrote in news:2ff47125-cffd-4909-b028-
:



On Jan 30, 8:41 am, WingFlaps wrote:
On Jan 30, 2:03 pm, wrote:

Out of curiosity I was wondering which civilian passenger airplanes
have the highest service ceilings? Wikipedia indicates that some
business jets have ceilings greater than 53000 ft or so while the 747
has only 43000 ft. Also why do large aircraft fly much lower than
their service ceilings? Usually I never see a large jet go beyond
37000 or so even on very long haul flights. I assume they would be
even more efficient if they flew close to service ceilings on long
haul flights.

Could be due to weight? When you fly across the Pacific the plane can
only get higher as fuel is burned.

Get higher? I thought that's what the continual small adjustments
effected by the trim wheels do to preclude, especially with the
AutoPilot engaged?

Huh?

Bertie

I meant to say that the AP will ensure that you keep flying at the
programmed altitude (through trim and throttle changes) instead of
letting the plane go higher with diminishing weight. Have I missed
something?

Ramapriya

D Ramapriya wrote in
:

On Jan 30, 2:08 pm, Bertie the Bunyip wrote:
D Ramapriya wrote in
news:2ff47125-cffd-4909-b028-
:



On Jan 30, 8:41 am, WingFlaps wrote:
On Jan 30, 2:03 pm, wrote:

Out of curiosity I was wondering which civilian passenger
airplanes have the highest service ceilings? Wikipedia indicates
that some business jets have ceilings greater than 53000 ft or
so while the 747 has only 43000 ft. Also why do large aircraft
fly much lower than their service ceilings? Usually I never see
a large jet go beyond 37000 or so even on very long haul
flights. I assume they would be even more efficient if they flew
close to service ceilings on long haul flights.

Could be due to weight? When you fly across the Pacific the plane
can only get higher as fuel is burned.

Get higher? I thought that's what the continual small adjustments
effected by the trim wheels do to preclude, especially with the
AutoPilot engaged?

Huh?

Bertie

I meant to say that the AP will ensure that you keep flying at the
programmed altitude (through trim and throttle changes) instead of
letting the plane go higher with diminishing weight. Have I missed
something?


We get cleared to an altitude and have to hold that altitude to avoid
running into other airplanes. The autopilot does not just go where it
pleases. Not yet, anyway.


Bertie