Optimum Altitude for a PC12 Pilatus
 

Hi,
Can you please help me out on this, it seems like I can't find an optimum altitude for a PC12 anywhere...
Thanks in advance.

How far are you flying? If you are flying the shortest scheduled route in the world from Westray to Papa Westray, a distance of around 2nm, then 1,000ft would possibly be the optimum altitude.

As a rule of thumb when I used to fly a Turbo-Commander we assumed that the optimum level was numerically the same as the flight distance. Therefore for a flight of 140nm the optimum level was FL140.

As with any airplane, optimum altitude is a function of GW.

There is a difference between "Optimum" altitude and "Recommended" altitude. As previous posters mentioned, on short flights climbing to optimum could actually result in wasted fuel.

Most of our routes are around 275nms and the Service Ceiling is 30,000' and we are always climbing that high for that distance, but I heard it from a couple of ATRs and Dash 8's Captains saying that even though their Service Ceiling is 25,000' but their optimum altitude is about 18,000'. So I thought that maybe we are misusing the PC12 for climbing very high.
Thanks for the input so far..

Ok so here's a tip, 2 actually!!

1/ look at your PC 12 perf charts
2/ next time try FL 180 and see what the time and fuel burn was for the sector, then compare to FL 250.

:ok:

Exactly!

Surely you have charts that give you TAS and F/B at various altitudes and conditions?

But, maximum altitude is rarely optimum altitude if it's performance limited.

Thanks! Will try to do so but it seems like nobody has never tried to do this with this particular plane. Then I will be happy to be the first one to probably find out the solution of this issue.

Can't leave wind or ISA deviation out of the equation either.

I find that VERY hard to believe.

It hardly seems credible that a pilot would make such a statement - and anyone in an organisation operating a PC12 or any other aeroplane would know where/how to find that info.

Edit; As the top item in my Google search for "PC12 performance" included cruise and long range cruise tables (admittedly for sim players, but the tables looked genuine) anyone can find this info at the touch of a button.

What's going on?

The rough rule of thumb that I used on the PC-12 was was (distance/10) + 2000'. So a trip of 190nm I would go to FL210. This, of course, does not take winds/weight into account. The PC-12 is an excellent climber with a very good wing, so you may as well go high and get your fuel burn down, plus have a few more minutes of glide time in your back pocket!

It's been 5 years since I've flown the PC-12, I miss it!

Thanks El Comat, that's exactly the rule we are using in our Company, in fact + 2000 varies according to the Elevation of point of Departure or Destination or both. After going through Performance Charts and your comments, I have decided to stick on this particular rule of Climbing high and play around with Tail winds as much as possible.

Given the PC12 speed, winds aloft are a major factor when deciding at what FL to cruise.

ant1
 

I totally agree with you:ok:.
Thanks!

our sectors average around that, flying the 1900 but a good rule of thumb was if less than 1.5 block a 40kt difference in wind we would stay lower ie 12-14k. But then again I don't worry about gliding range

I got some mates who fly the PC 12 they reckon they cruise at around 20/22,000ft - thats for about 800 NM.

First of all you have to tell us what kind of PC12 you are flying.
The old PC12 and the NG have a different max. ITT, so different Power and Speed at different altitudes.

The PT6 in the NG has a max ITT of 820°, but Pilatus recommends 780° max.
The older B engines have 760° max.

Useing 780 in icing condition, a heavy weight and flying minimum icing speed takes the aircraft very long to climb to cruising altitude.

The older PC12 have different max. Take Off weight.
There are 4700 kg for the -47
there are 4500 kg for the -45
and there are still a vew very old aircraft flying with 4200 kg max weight.

So tell us the Type and I will be able to help.

Inbalance
 

We have old and middle class PC12s 45 series, and we are always restricting our climbing ITT to 720 for longer engine life. I don't have any experience on NG and our Max takeoff weight is 4500 kgs.

To Natstrackalpha & Agaricus
 

Google? Ha ha. Well I'm a humble Man who always want to learn and never argues...
I had to ask this Question here because I tried to go through all the Performance Charts without any direct success, TAS for every altitude decreases with altitude but fuel flow also decreases during Climb for PC12. Long range Charts didn't work as well because for Optimum altitude you need good Speed not only low fuel flow.
Well I'm a little bit new on type about 400 hours but I'm not an inexperienced Pilot. I managed to get the Optimum Cruise Altitudes for B737s and Dash 8 series through compensations like this and experience on types.
Will appreciate your comment more than criticism:ok: