Simviation Forum - Gaining Altitude

Jan 4^th, 2006 at 8:38pm

Bubblehead Offline
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When a typical commercial jet takes off for a certain distant destination and plans to cruise at about 32K feet, does it try to get to the cruising altitude as quick as possible sacrificing speed (safe of course) or does it try to reach the ruising altitude gradually at a shallower angle but at faster airspeed.

Bubblehad

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Reply #1 - Jan 4^th, 2006 at 10:48pm

Mobius Offline
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I'd assume they would try to get to altitude as efficiently as possible as an airline doesn't seem to be the most profitable buisiness venture at this point, but I'm not positive. Wink

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Reply #2 - Jan 4^th, 2006 at 11:13pm

Nexus Offline
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Airliners usually climbs at fixed speeds.

Like 250kts below 10.000ft, and then maybe 310kts/m.82.
This will result in a gradual shallower climb as the airplane gets higher up in the air, and the air density decreases. But the crew wants the airplane to reach cruise altitude as fast as possible, since you burn less fuel up there

The climb speed is often determined by the Flight Management Computer, which tries to calculate the most efficient speed. It doesn't necessarily mean most economical, but rather a trade-off between time and fuel economy.

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Reply #3 - Jan 4^th, 2006 at 11:29pm

Triple_7 Ex Member

Depends on the pilot too i think. Ive been in a CRJ that tookoff and up to cruising altitude in no time but the way home i dont think we seemed to climb fairly slow and never leveled off before it was time to decend (>40 min air time)

Same with the 757s ive been on. Same routes but drasticaly different times till cruising.

Landing on the other hand...that is all depending on the weather and the pilot Roll Eyes

Been on a CRJ that bounced a couple times appon landing in Fort Wayne and yet the weather was perfectly clear with virtualy no wind Tongue

I think the pilot of that one was in a hurry though. Waisted no time in getting that thing into the air out of Detroit. You could hear the engines go from idle to full power in seconds...fastest takeoff and climb I've ever experianced Lips Sealed

In a few years hopefully i will be able to answer this question from the real experiance... Wink

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Reply #4 - Jan 4^th, 2006 at 11:45pm

Nexus Offline
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Triple 7, there are many reasons why the climb seemed shorter than on the return trip. Prevailing winds comes to mind as it can have a good 100kt impact on the groundspeed...which off course affects the time you spend during the cruise phase Wink

But they are still flying fixed airspeeds

The aircraft could also be lighter than during return leg. A lighter aircraft will pretty much fly the same airspeed as a heavy loaded, but the vertical speed will be greater.

And Fort Worth is in Dallas? From my understanding it is pretty hot there, regardless period? Hot air is by nature more "unstable" than cold air and can behave quite weird when you try to land. I've experienced that myself Grin

Edit: My bad, you wrote Fort WAYNE...which is obviously in my old neihbour state of Indiana (Used to live in Ohio Grin

) But the same scenario would still apply if it was a hot day

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Reply #5 - Jan 5^th, 2006 at 4:26am

Craig. Offline
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Of course the A340-300 is an exception, thats one of the most worrying to watch climbing, it looks like it wants to fall back to earth:)

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Reply #6 - Jan 5^th, 2006 at 10:27am

Rifleman Offline
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And the 340 feels the same from on the inside Craig, ......
.....although I felt the climb angle of the 330 was the highest of all the commercials which I've flown on.....especially since it only has two engines.........

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Reply #7 - Jan 5^th, 2006 at 10:44am

Craig. Offline
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Birmingham

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I must admit the A330 was fun to fly on. It had a heck of a long take off run, but that was because it was a hot night, high 80's but once in the air that sucker didnt hang around. Still didn't compair to the DC10 I went on first time around, that was a rocket.

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Reply #8 - Jan 5^th, 2006 at 12:48pm

EGNX Offline
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Leicester, England

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I thought that most airliners did staged climbs?
Where it would take-off, reach FL15 then gain speed and then climb up to FL34.... or am i miss understanding things? In Fs many of my airliners take quite a while to climb up to FL34 without a staged climb. ???

&&

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Reply #9 - Jan 5^th, 2006 at 6:43pm

Nexus Offline
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The greater of two evils...

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Quote:

I thought that most airliners did staged climbs?
Where it would take-off, reach FL15 then gain speed and then climb up to FL34.... or am i miss understanding things? In Fs many of my airliners take quite a while to climb up to FL34 without a staged climb. ???

Maybe you think about step climbs?
Those have nothing about gaining airspeed, but to burn off fuel. So when you're light enough to climb to a higher altitude, you simply dial in a new crz altitude on the autopilot and perform the step climb.

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