up and down

[darnoc]

Dear Readers

In real aviation, is there a policy on the amount of rate in ascending./climb or descending in the commercial airlines for 747. It seems
quite long to reach the cruising altitudesor to descend. ie. the min and max

Thank you

ST

[Sakakawea]

no I don't think so... but 747s are quite heavy aircrafts. They need a LOT engine thrust to climb quickly. and thrust is fuel... so they give
enough power to climb to reach their crusing altitude, but when they fly about 10 hours, it's ok to climb slowly to save fuel.

[DBE]

As "lil Toni" just mentioned, climb rates are calculated based on the most economical way to get an aircraft from level A to level B. It has
nothing to do with policies.

[poden]

Each aircraft type has a climb rate to weight relationship; this is approved by the certification authorities as part of the overall aircraft
certification. As far as I know, the FAA has no absolute upper limit on climb rates.

[Sakakawea]

DBE take care! "Lil Toni"'s boyfriend is a Marc too and she knows how to handle those guys

[darnoc]

Alright, thanks to all ....

[DBE]

Sakakawea wrote:
DBE take care! "Lil Toni"'s boyfriend is a Marc too and she knows how to handle those guys

Oh-oh..

[Canada_Boy]

Sakakawea wrote:
DBE take care! "Lil Toni" boyfriend is a Marc too and she knows how to handle those guys

Wow, a female on the forum. I thought we scared all of them away

Just kidding..... Actually we probably did scare them all away ( I could only remember one in the year I've been here "UKflygirl" )

[xhado13]

Canada_Boy wrote:

Sakakawea wrote:
DBE take care! "Lil Toni" boyfriend is a Marc too and she knows how to handle those guys

Wow, a female on the forum. I thought we scared all of them away

Just kidding..... Actually we probably did scare them all away ( I could only remember one in the year I've been here "UKflygirl" )

To be honest I thought she was a fake.

[JanniCash]

Back to the topic,

also the optimal, most economic altitude for jets depends on the gross weight. Fully loaded, with all tanks full this is much lower than when the
tanks are down to 20%. Therefore the most economic way to fly a jet over a long distance is to perform a technique that is called "step climb". You
start out at the Flight Level (FL) that is above the optimum for your takeoff weight minus estimated climb burn. When your weight has dropped enough
so that your current optimum is half between your current FL and the next available for your direction, you climb to that level. Assuming the
remaining flight distance is long enough to gain back what you spend for the climb. That way your aircraft stays pretty close to the optimum altitude.

The documentation I have for the 737-200 ADV with JT8D-15 power plants for example shows an optimum altitude of FL330 around 110000 lbs, FL350 around
100000 lbs and FL370 around 90000 lbs gross weight. The fuel penalty for flying below your optimum can be quite significant. Again, for a 737-200
flying at .74 Mach 8000 ft below optimum, the fuel penalty is as high as 15% and still an impressive 6% for 4000 ft below, while it is only 1% for
flying 2000 ft above optimum.

If there would be no ATC forcing you to specific flight levels, one could stay on a constant, very slow climb and maintain optimum. If there would be
no ATC.


Jan

[Sakakawea]

xhado13 wrote:

Canada_Boy wrote:

Sakakawea wrote:
DBE take care! "Lil Toni" boyfriend is a Marc too and she knows how to handle those guys

Wow, a female on the forum. I thought we scared all of them away

Just kidding..... Actually we probably did scare them all away ( I could only remember one in the year I've been here
"UKflygirl" )

To be honest I thought she was a fake.

thank you -_-