You are good to go as long as you had the turbo differences training and the retractable differences training in the SINGLE ENGINE class at any point in the past.
EASA FCL.710 (b)
If the variant has not been flown within a period of 2 years following the differences raining, further differences training or a proficiency check in that variant shall be required to maintain the privileges, except for types or variants within the single-engine piston and TMG class ratings. (my bold)
Unfortunately, due to the completely idiotic way the class ratings and related regulations are written, flying retractable turbo-charged twins does nothing here, since in EASA-land each individual twin normally requires differences training for the type, and there is no cross-crediting between classes.
An enlightened instructor, giving differences training on a retractable turbo-twin could, in principle, also endorse the Single Engine retractable and turbo, on the basis that a turbo-twin is a “suitable training device” for operating the gear lever and managing the engines, but if that hasn’t happened…
Funny, I was just about to post a question about this. If I understand it correctly, there are no variants for MEP aeroplanes. So is it really the case that this 2-year rule never applies, or are there any constellations under which it has an effect? I suppose it is relevant in the case of type ratings?
I would apply FORDEC here. They keep repeating this to us year after year in our CRM courses….
F: Facts – not really known well and/or very hard to understand. Ask three experts and get three different opinions.
O: Options
a) Just fly
b) Take official differences training (by whom? on what basis? on whose expenses?)
c) Fly circles around the airfield until you are confident with the aircraft (as you plan to do)
R: Risks
a) The aircraft gets damaged because of mishandling of the turbo installation – stupid questions will be asked
b) Some official will ask for my license and qualification to fly this thing
c) Some insurer will ask for my qualification to ferry this thing (this will definitely happen)
D: Decision
based on Oa Ob Oc and Ra Rb Rc.
This is the hard bit, because one must – more or less intuitively – set factors/odds for the various risks and options. The result will differ between different pilots.
My decision would be based on this:
Oa – easiest, low risk
Ob – complicated, expensive, not sure if it really satisfies the officials
Oc – useless. You have flown turbo aircraft before. They are all the same.
Ra – unlikely. Operating a turbo engine is not rocket science. You’ve done it before and live to tell the story. And it’s all explained in the manual.
Rb – unlikely. When did I last show my license and/or qualification to some official? (on SAFA checks doing commercial operations sometimes, but on a private flight? so long ago that I can’t remember)
Rc – he will be happy with the total flying experience and the previous turbo hours, no matter how long ago. The insurer was already there when EASA was not yet invented and he will still be there when EASA is a thing of the past. He knows what’s important and what is not.
So my personal decision would be: Just fly this thing wherever the owner wants to have it, don’t ask questions and don’t think twice.
E: Execution
Fill the tanks, wait for decent weather, start the engine, taxi to the runway and set takeoff power. If all pointers point to somewhere in the green arc, take off.
C: Check
After one or two or three legs flown, how does it feel? Am I confident to fly it? If not, get some local flying instructor and fly a couple of circuits with him and all will be fine…
Yes, I know, I am a German and should rather see it the regulator’s way. But like my insurer, I have seen regulators come and go. I know I can fly a Turbo Arrow (have never flown one before, but why should it be different from any other Arrow and why should it’s turbo engine be different from turbo engines I have flown on other aircraft?), so why hesitate for one moment to fly it?
unfortunately, EASA has decreed that unless “operational suitability data” exists, each individual type required differences training. Differences training requires “acquisition of knowledge” (theory), and “training in the aircraft or a suitable training device”.
So in principle you need differences training for each and every type of piston twin you fly, and do it again after two years of not flying that particular type.
https://www.easa.europa.eu/download/typerating-lists/EASA-T_R_List_Aircraft.pdf
“Unless determined by the OSD, differences training is required between all MEP (land) aircraft”, see page two of this document, which also contains the list of class-ratings-that-are-really-type-ratings piece of regulatory abuse.
I’ve been tearing my hair out already some time ago over that list, but thought I had got a grasp on its meaning. But now I’m confused. Until now, I thought that a “type” is always something that requires a “type rating”, otherwise you’re within a “class” which obviously works with a “class rating”. So all piston twins would fall in the MEP class, unless they are mentioned in that list. Looking for example at all the Piper airplanes, I find neither the Seminole nor the Seneca, so I would assume you don’t need “type” specific training for them.
Obviously my thinking was wrong.
But the mention of “variants” really seems to be a red herring in FCL.710 b) then, because on all classes where they exist they get exempted right away.
Ben wrote:
Do I need to go via official difference training or have I got “grandfather rights”?
Differences training is not bound to any form, so in case of the Turbo Arrow I’d grab a suitable instructor, talk to him about the system, fly a circuit, let him sign the logbook and treat him to lunch.
After all: If’ you’re asking many questions, you’ll get many answers…
I’m curious, what is it about a turbo that needs managing so carefully? Or, to put it another way, what goes wrong if mishandled?
Is it that one must avoid full throttle for long periods at low altitude perhaps?
Or perhaps the cooling after use must be managed by the pilot?
What if it’s turbo-normalised? Does that make handling easier?
Stickandrudderman wrote:
Or, to put it another way, what goes wrong if mishandled?
There was an accident in Damme, not too long ago, where a flight with a Turbo Twin Comanche – a really beautiful bird – ended in a field a couple hundred meters behind the airport, because the pilot had the two RayJays working at full power during takeoff. Just airborne he lost one engine, with a big black trail of smoke, and a couple of seconds later, he lost the second engine.
The point is with this difference training, that there is not too much to show in flight, if you have a capable pilot with an understanding of the systems. In the case of Ben, he already knows stuff from previous training, so it would just be a refresher and documentation. Same goes for difference trainings like variable pitch, single lever power control, glass cockpit or retractable gear. This can be done with ground school and an extended traffic circuit. Other difference training, like flying tailwheel aircraft, is much more on the piloting skill and even pilots with great aptitude need some more lessons to be proficient enough to be signed off on tailwheel aircraft. But there is no prescribed syllabus to any of them.
what_next wrote:
c) Some insurer will ask for my qualification to ferry this thing (this will definitely happen)
I just insured a turbocharged airplane capable of FL250, no questions asked. They did not even ask for experience in type or similar types. I tried to find an instructor for familiarisation. Some declined saying they had no experience in type. One who knows me well told me that since I knew I was capable of reading a manual and maintain an airspeed, I did not need him and would do just fine. That same instructor signed off my turbo variant a few years ago following a flight in his P210, but it might have been more than two years ago.
So what did I do? I read the manual like I always do before flying any new type of aircraft, thoroughly familiarised myself with the cockpit (I already knew the avionics), chose a day with good weather and little traffic (weekday), lit the fires and went flying.
what_next wrote:
When did I last show my license and/or qualification to some official?
In the course of 1 year I was tested for alcohol upon arrival at Eelde (EHGG) and had my license checked twice in France. That was after having flown for 20 years without having ever needed to show my license to anyone other than airport security to get airside.
In any event I am pretty sure you are not required to carry your pilot’s logbook, and I do not, so they would not have been able to check whether I had the required variants (although they do not apply to twins).
So I basically completely agree with what_next’s FORDEC analysis. We’ve had threads about variants here on EuroGA before, and I am not a big fan. The most important thing is that you evaluate your competency in light of previous experience, make sure that you understand the systems, feel comfortable with them, pick a day with no other threats than your lack of familiarity with the airplane and off you go.
Stickandrudderman wrote:
I’m curious, what is it about a turbo that needs managing so carefully? Or, to put it another way, what goes wrong if mishandled?
It is mostly engine temperature management.which is something that you should do in turbocharged (TC) and normally aspirated (NA) engines alike but which is probably even more important in a TC engine.
With a TC engine you get a new instrument labeled TIT (Turbine Inlet Temperature) with a hard limit that you must not exceed. Up high you can produce a lot more power than you would with a NA engine, but you have less cooling so you need to watch your temperatures (CHT) more closely. In order to increase engine life, you may also want to climb with reduced power. On a NA engine the power reduction will take place naturally in the climb, as the air density decreases. Not so with a TC.
You also need to understand the concept of overboost, watch your MP for any overboost condition (some planes have a warning light) and take appropriate action (reduce MP) if it occurs.
After landing you need to let your turbo cool down prior to shutting down.
During the pre-flight, if you have access to the components, you should inspect the turbine and ducts for signs of exhaust leakage.
If mishandled you can significantly reduce the life of your cylinders or kill the turbine. Some failure modes can cause a fire in your engine compartment.
I recently saw a picture of an airplane where a seam in the turbine housing caused hot gases to escape and burn through the cowling, but cannot find it right now.
