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Altitude for short commuter flights

Pro Member First Officer
michlin First Officer

I base many of my flights out of Boston's Logan airport. One flight I like to do is a commuter flight from KBOS to JFK which is about 185 nm. What would be an appropriate altitude for a commercial airliner for this 40 minute flight?

TIA,
michlin

TehCookie Guest

40 minute flight..? I am no pro, but I would guess around 15,000-20,000?

Pro Member Chief Captain
Alex (Fire_Emblem_Master) Chief Captain

What are you flying first of all?

OK, 15-20,000 feet is waaaay to low. It'd be ok for a 20 minute flight, but you get way better gas mileage at higher altitudes.

Firstly, let's look at your aircraft options.

Since I don't know of a lot of piston props that do commuter work in modern times, lets go to turboprops. A B1900D for example, (Beechcraft commuter plane), on a flight like that, would be ok at around 18,000. BUT, if you are doing a CRJ flight, or any other jet, shoot for 25-28,000 feet. When you climb out of a airport, don't climb at 1,000FPM, shoot out of there at around 22-2500FPM. Yes, real planes do that because you won't save a LOT in gas by climbing slower with a lower power setting. You takeoff with around 88-90% N1 under nearly all circumstances, so you can afford to climb at 2300FPM. Now, after 10,000 feet however, reduce rate of climb to around 1600FPM up to 18,000. Then around 1000-1200FPM the rest of the way.

Pro Member Trainee
rogersam6 Trainee

I fly at around FL 180-Fl 220 for my flights between Bos and PWM 🙂

Pro Member First Officer
michlin First Officer

A jet ariliners such as a 737. A few years ago I was on a 20 minute jet flight, Oahu > Maui. We got up to 12500 - 13000. So I wondered if a 40 minute flight may go to 20K. I wanted to get some of your opinions for a comparison. Thank you.

FEM,

Thank you for your additional imput.

Pro Member Chief Captain
Alex (Fire_Emblem_Master) Chief Captain

you're welcome

Good luck!

Pro Member First Officer
leadfoot First Officer

As a general rule on short hops in airliners, you should spend no more than a third of your flight time climbing. So if it takes 45 min for the flt, only spend 15 min in climb.------1/3 climb, 1/3 cruise, 1/3 descent.

Pro Member First Officer
michlin First Officer

leadfoot wrote:

As a general rule on short hops in airliners, you should spend no more than a third of your flight time climbing. So if it takes 45 min for the flt, only spend 15 min in climb.------1/3 climb, 1/3 cruise, 1/3 descent.

Thanks, leadfoot! 🙂

Pro Member Chief Captain
Alex (Fire_Emblem_Master) Chief Captain

You can get 28,000 in exactly 15 minutes if you climb out at 1800FPM the entire way, if you climb out at 2300 untill 10,000, its even faster!

Pro Member First Officer
Rambunctious First Officer

Fire_Emblem_Master wrote:

OK, 15-20,000 feet is waaaay to low. It'd be ok for a 20 minute flight, but you get way better gas mileage at higher altitudes.

That's not quite correct, it depends on the direction & speed of the wind at the level you want. You can have infinite different scenarios in one flightpath.

It's a tradeoff between this, and the time & fuel used to get there. If it's busy airspace, and there's a lot of trans-continental jets around, a lower altitude is often not only usual, but the most probable. The gain in speed, assuming you do get a tail wind can easily be eaten up by ATC transitions if the wind wasn't enough gain (as is often the case on a short leg) - 180 odd NM at an average 250Kts is less than 45 minutes...

Elkin Guest

A good rule of thumb is for every minute of flight time equals 1000 of altitude. Variations apply, but it is very close. (I.e. 7min= 7k)

Turboprops run best at around 15 to 20 thou. While the jets want to be at 25+ Jets want to be as high as possible as quick as possible. But!!!!! a hard climb can burn more fuel than a cruise climb and and and.

There are variables.

What's Up FEM?!?!

Pro Member Chief Captain
Alex (Fire_Emblem_Master) Chief Captain

The gain in speed, assuming you do get a tail wind can easily be eaten up by ATC transitions if the wind wasn't enough gain (as is often the case on a short leg) - 180 odd NM at an average 250Kts is less than 45 minutes...

I think you contradicted yourself twice there...the gain can be eaten up by ATC if there wasn't enough gain...yes, thats true...now what???

First, I'm not talking about speed, I'm talking about fuel burn in regards to altitude, because you're not about to tell me that a B737, or ANY jet for that matter is going to get the same fuel burn in relation to altitude.

I'm also not talking about tailwind either, this is assuming normal flight conditions, using a B737.

A B737 gets a fuel burn of approxx 4,000LB/HR at 10,000 feet at 250 KIAS. At FL250 however, you get a fuel burn of around 3,000. 1,000lb less than at the lower altitude, and, using a economy climb rate of 2300F/M past 10,000, then 1600 to cruise, you end up burning less fuel overall than you would at a lower altitude cruise, and, you can cruise at a faster speed for less fuel burn. Also, you're up above the turbulence usually encountered at a lower altitude, thus giving your virtual passengers a more smooth ride.

PH Guest

There are far too many variables to give a "correct" answer on this. Quite simply as already stated altitude=economy. However the most important factor which I do not think has been mentioned is WAT. Weight is a very significant factor here....you may have a full load you may be empty, you most probably will not have full fuel for a short sector but you could be tankering. Climb restrictions regarding the departure airport may also limit your climb (not on Boston-JFK) but something to consider, finally temperature is also worth considering.
Again it has been pointed out are we talking nil wind?
In the real world there will be ATC restrictions, aircraft limitations, geographic issues etc. For flight sim select low fuel level check the POH for best rate of climb speed (Vy) and for 45 miles I would not imagine you would need to go over fl150 as a slow descent will give you a 45 mile glide from fl150. Happy flying.
paul.hand1@virgin.net

Pro Member First Officer
coolsan First Officer

I second PH on that there are too many variables to give one correct answer.....Another thing to consider is the altitude of departure and arrival airports. For example, on a flight from Acapulco to Mexico City you usually go up to FL290 or so and they are about 190nm.
Acapulco is at sea level, but Mexico City has an altitude of about 7500ft.

I know the following guide is not for an aicraft designed for short commuter flights, but it gives the basics of climb, cruise and descent which you can adjust to your specific needs.

Pro Member First Officer
michlin First Officer

coolsan,

Cool! 😀 The Boeing 757 site is a good find.

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