Nevertheless, I think it is not a good thing that Socata does not provide these figures. If you can get there, there should be a table saying what it’s gonna take to do it.
How do you feed a flight planner without this data? TFD/C/D is absoutely needed in most applications (and often enough you have to calculate those yourself out of graphs for VS and other factors) as well as performance data. If there is nothing in the TB20 manual, then you are on your own up there and basically have to test fly the airplane in order to get figures you can then use. Whether they are legal to use is the next question… imagine having to answer to an AAIB or CAA official on what basis did you calculate your PLOG if you planned for FL180 but only have figures in the book up to 12500 ft…
Just had a look at the PIH Peter has on his site. This is really astonishing, how this could have gotten past certification. All the tables end at 12500 ft and then they call a maximum performance altitude (I reckon that means service ceiling) of 18000 ft. So where is the rest of the data? Socata please?
The only other variant I see is that someone who has the proper instrumentation e.t.c. (TAS/FF/e.t.c.) would have to test fly it and share the data (with disclaimer) with the rest of the community.
I just had a look at some of my other POH’s, did not really find any other one lacking such vital stuff. My own states a service ceiling of 17500 ft, climb performance table goes up to 20k ft and there are cruise data for 15000 ft. That is 2500 ft not covered in the upper levels, but not 5500 ft…
I wonder how diffiult it is to get CAA’s to accept a properly done POH for such airplanes where the originals are so far out of sync with reality (also due to mods and upgrades) that you in fact need to rewrite a proper book on it so that you can tell people how to operate the airplane. Airlines do this all the time, but I suppose they have the ressources to do it. For example, for the early Mooneys we lack checklists, emergency checklists, time fuel distance tables e.t.c. I made some for myself out of sources who also made them for themselfs, but I really wonder how things are legally on this. In the end, you need something to work with, but where do you get it.
LeSving wrote:
I guess, but with no performance data, I would think there is not enough power left to gain any performance by doing so.
No. It means nothing else than that Socata did not think it necessary to provide the data. Lazyness on their part.
The TB20 will go up to even higher than the 18000 ft indicated in the PIH I have here saying that is the maximum performance altitude. It can in fact go up to about 21000 ft given enough time.
At 12’500 ft the engine according to Socata produces 60% power at 2500 RPM and 17.5 GPH and produces a TAS of 154 kts up there. At the same time, it produces a rate of climb of 332 fpm with 95 kts IAS. That is more than enough indication that it has a lot of reserve left to climb after that. Looking at the manual, the altitude where ROC goes below 100 fpm is 18’000 ft. So in between there, it is somewhere between 300 and those 100 fpm. There is also no indication of the absolute ceiling.
Peter has flown the TB20 up to over 20k ft, so it is possible. This leaves about 1/3rd of the whole altitude spectrum without data. I find this not very pleasant at all.
Most NA airplanes can reach FL150 or higher. In my airplane, the service ceiling according to the POH is around 17500 ft, the absolute ceiling at MTOW-climb fuel is over 19000 ft. With a lighter airplane, it can be a lot higher still.
Also a G tb20 can do 20000ft whereas a N tb20 can only do 18000ft.
Also the G one can be flight planned for icing conditions.
Clever how that works 
Give me isa minus 15 and I will get 23000ft. I was climbing at 300fpm at FL195… but atc would not let me go higher.
For the Turbo Arrow IV the handbook provides data to 20000ft. I have never been that high though.
Peter_Mundy wrote:
Turbo Arrow IV the handbook provides data to 20000ft.
IIRC that plane has an altitude limitation of FL200. I’ve taken it to FL200 to avoid a nasty mountain wave in the Rockies, west of Denver.
Indeed it does
“Flight above 20.000 feet is not approved. Flight up to and including 20.000 feet is approved if equipped with oxygen in accordance with FAR 23.1441 and avionics in accordance with FAR 91 or FAR 135”
Some POH include data all the way up to the service ceiling, some don’t. My guess is this has some to do with the rate of climb, and the likelyhood that anybody would actually try to get there. Add various other limits on top (oxygen, etc..)
But performance higher up on a NA engine is not difficult to extrapolate from the lower data. Just keep in mind the engine and prop care about DA (not PA).
For Achim’s router, I generated the rates of climb using linear interpolation from 1000fpm at MSL to zero at 20000ft.
It seems to work well enough.
The actual flight is nothing like the plan, because – for engine management reasons – I prefer to climb more slowly. The Eurocontrol validation margins are pretty wide (though I was told they are not public, to prevent disclosure of manufacturer-confidential performance data!!!) and even FlightPlanPro works fine with a very different aircraft type selected (e.g. a turbo Bonanza instead of a TB20).
Peter wrote:
I have done FL210. I posted a pic of the altimeter here but can’t find it right now.
;-)
The attitude is interesting. What did the ASI show?
