Required hours for test flight? 25 or 40?

[JetPilot]

Some guys are required a 25 hour flight test period...others a 40 hour. What determines the difference? A certified engine and prop? Where can I find this rule? I can't find it in the AC or part 21...thanks

[redbeardmark]

Originally Posted by JetPilot

Some guys are required a 25 hour flight test period...others a 40 hour. What determines the difference? A certified engine and prop? Where can I find this rule? I can't find it in the AC or part 21...thanks

I don't know what the rules say, but it seems that if you have an experimental engine/prop you get the opportunity to test for 40 hours. Certificated engine/prop gets 25 hours. Or, that's how it seems. I put in an Aero Sport Power engine and Catto prop thereby earning 40 hours of test time. The good thing about this is that by the time you're done flying the 40 hours, the only bugs that remain are on the windscreen

There is probably someone out there that can point you to the exact
regulation.

Mark Andrews.
N598X

[txaviator]

This is an interesting discussion, especially with regard to the talk of "certified" engines and props.

I recently attended an RV builder class, and the instructor stated numerous times, that "even if you were to buy a brand new Lycoming, from Lycoming, in the crate...just as soon as it is bolted to an experimental plane, it is no longer certified in any way, shape or form".

Perhaps I am just missing something here, with regard to the word 'certified'? From what I am told, certified does not apply or have any bearing on anything?

[rvpilot]

This is out of AC20-27E, CERTIFICATION AND OPERATION OF AMATEUR-BUILT AIRCRAFT:
a. Amateur-built aircraft will initially be limited to operation within an assigned flight test area for a
minimum of 25 hours when a type certificated (FAA-approved) engine/propeller combination is installed, or 40
hours when a non-type certificated engine/propeller combination is installed.
I would take this to mean a engine/propellor combination that has been FAA certified for use on other aircraft (other than experimental). When you put an uncertified prop, IE a Catto, it becomes an uncertified combination, thus a 40 hour test period.
Other comments?
Bill Waters

[f1rocket]

If your engine has a data plate from Lycoming on it and your prop is certified for that particular Lycoming model, then you will get 25 hours. Anything else gets you 40 hours. You will have to show the inspector the certification sheet for the prop to prove to him it is a certified combination.

Now, if you pull that Lycoming off your experimental and try to sell it, it cannot go into a certified airplane again unless it is completely remanufactured (not rebuilt) by a certified engine shop. It has to do with the fact that on a certified engine, the parts from the same engine stay with the engine until they get replaced. When it's remanufactured, it's a new engine again and it comes with a new logbook. On an experimental engine, parts from different engines can be mixed and matched as long as they are within tolerances for a rebuilt or a remanufacture. That's why Aero Sport Power engines come with a new data plate that identify it as a "Aero Sport Power O-360" instead of a Lycoming.

However, the Feds do make mistakes. I got only 25 hours on my RV-6 because the inspector failed to notice that the engine was from Bart instead of from Lycoming. My Sensenich metal prop was certified for my O-320 so he only gave me 25.

For a simple, VFR airplane, 25 hours of testing is usually enough. But I almost prefer the regime of a 40 hour test period because you really need it to do flight testing properly on a more complicated airplane, just my $.02.

[JetPilot]

You guys are great. I read that crazy Part 21 until I was totally bored and could not find the info. I have a 0 SMOH lyc IO-360-A1A (200hp)....now I need to find a used certified FP prop...if you hear of one...please let me know.

[Kevin Horton]

Originally Posted by JetPilot

You guys are great. I read that crazy Part 21 until I was totally bored and could not find the info. I have a 0 SMOH lyc IO-360-A1A (200hp)....now I need to find a used certified FP prop...if you hear of one...please let me know.

I'm not aware of any certified FP props for that engine that were designed for aircraft as fast as RVs. I believe that any certified FP you find will have way too low a pitch, which would give a fantastic climb, but would greatly reduce your cruise speed.

Bite the bullet on the 40 test phase and get a non-certified prop that is suited to an RV. Or, spend the bucks and get a certified CS prop.