How high can turbo piston aircraft really go?

Here’s a classic.

The Mooney M20K 231 has a service ceiling of 24,000ft while the 252 (such as Terbang is currently flying on his South American adventure) with intercooler and automatic wastegate was certified to 28,000ft…I’m not sure but I think this was later reduced for the long body turbo Mooneys…

indeed, it was reduced to FL250 with the Mooney 20M (TLS or Bravo).
FL280 is IIRC the maximum for unpressurized certified aircraft. If oxygen supply is disrupted the time of useful consciousness will be somewhere between 2,5 – 3 min.

highflyer wrote:

In another forum someone claimed he’d been at 31k feet with his Cessna T182T.

This is of great interest to me. Could you please give the link?

https://www.pilotundflugzeug.de/forum/2013,05,23,19,5338795/page3 (last post of the 20th October)

“oben herum ist der Lyco also flotter aber bei enormem Verbrauch und großer thermischer Belastung. „

Stimmt. 165 KTS sind möglich. Verbrauch ist genauso wie immer: 13,5 gph und 155 KTS auf FL190. Ich fliege oft auf FL190, manchmal auch höher mit meiner T182T. Nur im Sommer, wenn es ganz warm ist, muß ich die Cowl Flaps einen oder zwei Strich öffnen, weil die Öltemperatur sonst über 200 degF geht. CHT, EGT, TIT sind immer gleich, ziemlich egal, in welcher Höhe man fliegt. Zum Glück gibt es „Frau Behrle“ nicht mehr, die würde mich schimpfen: Vor vielen Jahren bin ich einmal auf FL310 geflogen. Auch dort waren alle Temperaturen völlig unverändert im Grünen. [Ja ich weiß, das hätte ich nicht tun sollen, verstößt gegen die max. Operating Altitude, ich dachte aber damals fälschlicherweise, das wäre nicht limitierend.] Also, große thermische Belastung läßt sich zumindest von den Motoreninstrumenten nicht erkennen.

Gerd

John Deakin flew his Bonanza up to FL270 for a trial of something like that. The problem with this kind of flying is not the engine normally, even though also there limits are likely to be met, but human performance. I guess FL200-220 in an unpressurized plane should be plenty with 250 as an exception maybe, but above that, things can go bad REALLY fast if there is a lack of oxygen for some reason.

Also most non turbos can do FL200, if slower and with no reserve. The question whether you really need a turbo for what you do is if you want to go higher than that on occasion.

Personally I did like the manual Rajay Turbo normalizers which can be added to most non-turbo engines, quite some Twin Commanches and also Seneca I have them, I´ve also seen them on classic Mooneys. Best of two worlds. You CAN fly with the turbo if you need, but you don´t have to. It will give you a distinct speed advantage at altitude plus of course the capability of flying higher.

achimha wrote:

ATC can see the type of aircraft and theoretically know that it’s an exceedance of the type certificate.

I had this experiance this year. The controller did ask of the type of aircraft while cruising at FL220 in order to avoid bad weather. A minute later I got " descend FL200".
For me it`s a clear safety reason to fly that high VMC on top to avoid icing conditions below. What has priority in these circumstances, safety or type certificate?

europaxs wrote:

Vor vielen Jahren bin ich einmal auf FL310 geflogen

That is amazing, many thanks for the link. I would be happy to fly at FL250 (outside german airspace as a test flight)

highflyer wrote:

What has priority in these circumstances, safety or type certificate?

I would prefer to not have to answer this question in a letter from a state attorney along with indisputable data supplied by DFS. Not saying I ever heard about such a case but I’d be careful and only pull that joker card if I really have to. Like flying over gross, etc.

I would be surprised if the controller had the data, or even cared… more likely curiosity.

On those two occasions when I cruised at FL240 (in a Columbia), what felt like every controller asked what I was flying, since these altitudes are either empty or the realm of turboprops. They all were curious as I was “too high and too fast for a piston aircraft, and too slow for a TP”. And it was at night, so they probably were bored, too.

I have taken my Navajo up to F280. The limiting factor was not the engines, it was still going up as fast as it would have been at sea level, but blood oxygen. My passenger’s fell off a cliff, so I descended rapidly.

But the aircraft gave the impression that it would just keep going.