Time or Fuel economy

[2000flyer]

and to the person in the C650, that's ridiculous to climb to 410 on a 500 mile leg!! now, that's not thinkin period.... lol

I disagree with you here. On trips in excess of 350-400 miles, we'll usually try somewhere between FL390-430. Depends on the route, winds, etc. Flying up the east coast, it often doesn't make sense to go to FL410 as you start down barely after level-off. It takes about 5 seconds to recomputer a flight plan at a different flight level to see which provides the best time vs. best fuel.

Typical for our aircraft is to figure between 140-160 miles (give or take) to climb to FL390/410. Lets just say 150 for this discussion. So now you have 350 miles to go to destination (using your "500" mile trip). A typical descent will start 100-120 miles out, closer if you have a helpful controller. So you'll be at cruise for some 250 miles or so. Did you lose time going to FL410? Obviously, if you climbed into stronger headwinds, you screwed up.

A good rule I follow is the "10" rule. Example: 200 mile trip, FL200. 280 mile trip, FL280, etc. Generally works out pretty good, but obviously, use common sense.

2000Flyer

 

[Headwind]

We use the "10" rule to determine cruise altitude. On climb we climb steeper with a tail wind and more shallow with a headwind. On descent ( if ATC gives us the option) we start down, in miles, at 3 times our altitude. Example: FL250= 75 mles FL350= 105 miles and try to think of MMO as a goal. With luck the speed you lose in the climb will be of-set with increased speed in the
descent.
The "10" rule works very well on a Cheyenne to FL250, BE- B200 to FL290, and Citation I or II to FL390 and only go higher under ideal situations.

Headwind

 

[LearjetGA]

I use a slightly different rule of thumb, it is applicable to turbojets only since it asks for a fast climb. Take 10 % of the distance and add 5. 200 miles is FL 250. 300 miles is FL350

 

[banned username 2]

I use a slightly different rule of thumb, it is applicable to turbojets only since it asks for a fast climb. Take 10 % of the distance and add 5. 200 miles is FL 250. 300 miles is FL350

I agree, I typically use the "10 plus 5" rule... 260 mile trip = FL260 plus 5 = FL310

Going high can have it's benefits too... more likely direct routings, less traffic, lighter winds (if facing a headwind), better fuel burns, usually above the weather, looking down on the airliners...

Did I just say that?

 

[pa56pa]

Flying up the east coast, it often doesn't make sense to go to FL410 as you start down barely after level-off. It takes about 5 seconds to recomputer a flight plan at a different flight level to see which provides the best time vs. best fuel.

I stand corrected.. I had a notion of a typical 500 mi. west coast, i.e. SFO-SAN and you're right, it depends on the route, etc. But say anything east of CA, I too would go 390 and/or above. I guess "I" wasn't thinkin ...

Oh, and thanks for the 10 plus 5 rule, I'll keep that in mind..