[STEVE]

STEVE on February 1, 2021 at 11:27 am #20487

Hi,
There seems to be a split in opinion over which company–the airframe manufacturer or the engine manufacturer–is responsible for detailing the correct way to operate and care for a supercharger.
As both you and Patricio have pointed out, Piper POH s have scant information on how to operate an engine/turbocharger combination.
Some rigid rules I know of include a redline of 1650 deg F for the turbine inlet temperature, and the insistence that even after a low power approach, landing and taxi the engine should be idled for 5 minutes after reaching the parking spot.
Here’s is a write up concerning this: https://twinandturbine.com/article/insiders-guide-trouble-free-turbocharger-operation/
In my opinion this 5 minute rule is always best, but I rarely see it any more at airports. Most pilots consider the time from power off prior to touchdown to final brake application and stop at the parking spot as part of that 5 minute cool down period.
They reason that in almost all cases they have been reducing power since they started letdown and approach so the turbo charger unit has already began to cool down.
The FAA has published a best practices guide. You can find it here: https://www.faa.gov/aircraft/air_cert/design_approvals/small_airplanes/cos/aging_aircraft/media/maintaining_exhaust_system_best_practices.pdf.
There are also a number of YouTube videos–I suggest you type turbocharger best practices into the YouTube search bar.
Steve

[Thomas Dorl]

Thomas Dorl on January 31, 2021 at 8:19 am #20486

Good discussion… the flight school were I fly recently bought a Turbo Seminole and was surprised to see little information in the POH. We found a few bits in the maintenance manual, can any provide some additional resources? We have read thru FAA publications on turbo, but looking for more specifics

Thanks
Tom

[Patricio Levenzon]

Patricio Levenzon on January 27, 2021 at 2:01 pm #20482

[color=black]Hi Steve,

Thank you for you kind reply and comments. I have read the article you have indicated which contains interesting information and I have also reviewed Continental Aircraft Engine Installation and Operation Manual (10/2017). As you know, engine cooling is frequently suggested considering a cooling down period that goes from 1 to 7 minutes. As it didn’t make sense to me, yesterday after a 30-minute flight, once landed the temperature was measured on the exhaust surface and the exhaust gases. The surface temperature was measured using a thermal imager and it reached 105°C on the average. The exhaust gases reached a maximum[/color] temperature of 220°C and a minimum of 200°C which were measured with a TIF 8800 using a special probe, These temperatures were measured during the 5-minute “cooling down” period. As you can see, there were no significant temperature variations but those 5 minutes are recommendable for turbo spin-down purposes, as also mentioned in the above Continental manual.

What I don’t understand, however, is that my aircraft POH does not contain any information on the turbocharger.

I assume that if it’s not prohibited in the POH, touch and go maneuvers can be performed.

Thank you!

Best regards from Chile,

Patricio

[STEVE]

STEVE on January 25, 2021 at 1:35 pm #20480

Hi Patricio;
In seeking a credible answer to this question, I called the owner of Main Turbo in Visalia, CA. He told me he was more worried about how sudden power changes would affect the engine, not the turbo.
He suggested that power changes–both up and down–should be gradual.
Which is a good idea in all situations.
I suggest you read the following article:
https://www.avweb.com/ownership/shock-cooling-time-to-kill-the-myth/
In it, Rick Durden lays out some facts that support the idea that shock cooling is a myth.
Once you read the article, and if you have any questions, please get back to me and we will discuss this further.
Best,
Steve

[Patricio Levenzon]

Patricio Levenzon on January 21, 2021 at 12:42 pm #20466

Dear All,

I have recently purchased Piper Arrow PA-28 R 201T manufactured in 1978 (Frame S/N 28R-7803250). The 600 series turbocharger (P/N 646396) has just been replaced during the 100-hour inspection due to a a small crack (we have complied with the relevant AD).

Surprisingly, the aircraft manual and all revisions up to 2012 do not include any information on the turbocharger “limitations” and correct operation. The engine manual only indicates the cooling time after a flight (5 minutes before the engine can be turned off)).

My question is : Can touch and go be performed with this particular aircraft? As well as 180-degree turn emergency simulations?

Thank you in advance for your comments.

Best regards,

Patricio Levenzon