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Old 5th Feb 2005, 22:38
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Just some info please

Hello

I would like to know what maybe to some guys a very simple/silly question but how do professional pilots get a figure on cruise altitude?
I am very intersetd in avaition and have many DVD's...i would just like to know how they work out what a cruise altitude should be on a short internal flight from say EGNM-EGNT in the uk would be compaired to a long haul flight from EGLL-KLAX? For instance?

And what is Transition altitude?
Is it the safe altitude around an airport..??
These questions would make watching my DVD's more understandable?

Kind Regards Paul Teasdale
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Old 5th Feb 2005, 23:27
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Dear Rubberball,

I think that each answer to your questions will lead to further questions, such is the nature of aviation.

May I strongly recommend that you sate your interest in aviation by taking a ground school at your nearest aviation facility?

You will be shocked and amazed by the wonders of aviation.

I still am after 25 years!!!!!!

VRT
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Old 6th Feb 2005, 01:52
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Hi rubberball!

For big aircraft you have a graph in which knowing your take off weight and trip distance you find the optimum altitude for the short hops, which differs from the optimum altitude.

For long trips you have optimum altitude charts for a given weight and atmospheric conditions. Normally as you burn fuel and become lighter you climb to the new optimum altitude in such long flights as EGLL-KLAX ones (and even in shorter ones).

Transition altitude is the altitude where you have to change your altimeter setting from standard (1013 milibars or 29.92 inHg) to the local altimeter setting (in your videos you may hear QNH, and it's the actual pressure the airfield may had if it was at sea level, or QFE if it's the actual air pressure at the airfield). It's purpose is to have an accurate altimeter reading near ground.

The safe altitude around an airport is MSA (Minimum Sector Altitude), which is published in the charts, and guaratees a 1000' obstacle clearance within 25NM from a navaid (usually in the airport or very close). You can have from just one MSA to up to normally 4-5 for different sectors. Its like when you cut a round cake in pieces.

Hope that you understand this terms and please feel welcome to ask whatever you want.

Regards,

Pablo
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Old 6th Feb 2005, 03:27
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how do professional pilots get a figure on cruise altitude?
They look in the books! That's what Performance Manuals are written for!
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Old 7th Mar 2005, 18:49
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short-segment cruise

I once encountered a carrier who wanted to fly an "up then down" profile on short segments. In other words, climb until you intersect the descent slope, with zero cruise length. According to the book it yielded minimum fuel burn.

We talked him out of it - top of climb is the most severe point for the engine, and it does no good to retard immediately to F/I. Added fuel will be cheaper than turbine distress.
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Old 8th Mar 2005, 04:55
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Intruder:

What about the flight plan produced by ops and the FMC???

To be honest these are better and easier methods than flicking through a book!!!

They look in the books! That's what Performance Manuals are written for!
In future I suggest you lighten up and stop being an arrogant TW**T!!!

Rubberball:
If you have any more questions, feel free to PM me and I will do my best to answer them!!!
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Old 8th Mar 2005, 07:27
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Pablo, you got that the wrong way round:
TRANSITION ALTITUDE is used during the climb when you have your altimeter set to QNH (ie local mean sea level pressure- so you get your altitude reading in relation to local terrain right)- at Transition Altitude you switch to STANDARD SETTING 1013mbs/29.92 inches so that everyone is flying to the same setting.
TRANSITION LEVEL is used during the descent when you have your altimeter set to 1013mbs/29.92 inches, and you want to get nearer the ground so it makes more sense to set local QNH so you can get an idea of your proximity to local terrain. Transition is at 18,000'/FL180 in the US, and usually about 6000'/FL70 in the UK- you just look on the airport approach chart to see what it is. The difference doesn't matter- you just do it.

That some people persist in going to QFE (local airport pressure- so altimeter reads zero on the ground) completely mystifies me. Your chart shows terrain up to xxxx feet- having QNH set will instantly tell you whether you are likely to bump into it-in short, QFE is useless, but it has its fans for some strange reason! I'm far more interested in knowing my height over terrain than my height above a runway when I'm threading through variable terrain!
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