Engine build choice in relation to Phase one flight these duration.

Phase one is usually either the first 25 or 40 hours depending on factors such as powerplant and propeller.
Obviously a converted car motor calls for a 40 Hr phase one, no issue.

Now if a certified engine allows for a 25 hr phase one test, just how certified does it need to be? Lets consider an O-360 mounted to the nose. To be truly certified it should have it's original MS carb and a pair of mags hung on it's back.
But many of these engines now have a higher compression, electronic ignition offering a proper advance curve which eases loading on the cylinders while improving power and fuel burn rates. And a change to fuel injection which may not be based on standard low pressure heritage systems.
At what point would this O-360 not be considered a certified engine in today's E-AB world and be accepted for a 25Hr Phase one test program?
There are so many Lycoming "look alikes" out there now and I presume these all qualify as a certified motor even if it has an SDS injection system?

A friend of mine just finished his experimental cub with a certified engine and a catto prop, DAR requiring 40 hours because of the prop.

Both engine and prop have to meet the TC and be Airworthy to get the reduced phase 1 limitation. The policy is spelled out in Order 8130.2H, soon to be J.


Sent from my iPhone using Tapatalk

So I wonder if the new 80" Sensenich STOL prop will be accepted for the engine, probably not. Sounds like flying off the first 25 with an old aluminum club then add the 5Hr addition when you swap to a modern prop will cover this should one not otherwise need the full 40Hrs. This kind of defeats much of the initial flight testing since the plane will have a measurable CG change.
Good to know this since I was expecting it was controllable props that would bring the plane into the 40Hr.

I am still curious if changing the induction and mags trips the engine into the 40Hr?

Charlie, Build the plane the way you want it and don't worry about the number of hours required for phase 1. You can position the flight test area in a location which is most useful for yourself. It will not take long to acquire 40 hours. You will find that a 50 mile diameter circle covers a lot of territory.

You are correct Peter, just my head keeps searching for answers to questions that many times do not matter. I will still have plenty of learning to do once I achieve getting this plane in the air.
Allot has changed since the last time I put a certified engine on a homebuilt, way back then the engines were used generally as you pulled it off the donor. I look at the O-360 I have sitting here and feel the need to change things to what I will be comfortable with which is not having 60 Yo tractor parts on it.

I used an unmodified IO-360 with the exception of replacing the mags with Pmags and using an uncertified prop so had 40 hours. My territory is restricted to the north by the Boston class B airspace so I centered the test area at Plymouth which is 10 miles south of here. There were very few times when I may have been tempted to stray beyond the boundary prior to the 40 hours.

Ok, here's the deal that most people miss when discussing the phase 1 time. The engine and propeller have to be certificated IN COMBINATION in order to get the 25 hour phase one. That means that the applicant must be able to show a type certificate data sheet that shows that specific engine and propeller combination approved on a TCed airplane. Just a TCed engine and a TCed prop by themselves don't cut it. The specific combination must appear on a type certificate in order to get the 25 hours.

Remember that it's the applicant's responsibility to prove that the certificated combination exists. The FAA inspector or DAR isn't going to do the research. If the applicant doesn't have the supporting documentation, the phase 1 will be 40 hours.

Also remember that ANY change to the engine that moves it away from it's TCed configuration gets the 40 hours. We typically see things like replacing a magneto (or both magnetos) with electronic ignition. This will get you a 40 hour phase 1, because the engine doesn't meet its type-certificated configuration.

jnorris said:

Also remember that ANY change to the engine that moves it away from it's TCed configuration gets the 40 hours. We typically see things like replacing a magneto (or both magnetos) with electronic ignition. This will get you a 40 hour phase 1, because the engine doesn't meet its type-certificated configuration.

Click to expand...

This is a good enough reason to start with all of your desired modifications in place from day one.

And as stated before, when and if you make a change in the configuration, you would need to place yourself back in Phase 1 for 5 hours, bringing the total phase 1 to 30 if you change a TCd prop engine configuration. If you really want a specific configuration, start with that and take advantage of the 40 hour phase 1 and actually do the testing spelled out in the guide. All to often I see guys just build hours without actually testing anything. I usually ask for a test plan when I do a certification so I can see that they are at least thinking about it.


Sent from my iPhone using Tapatalk

Frankly, if a person actually tests the airplane like they should, it will take nearly 40 hours anyway. As mentioned above, there are a lot of homebuilts that get "tested" by simply flying around for 40 hours. There's more to it than that!

I am a person that believes in testing and development, this is part of how I earn my living. If I were building a totally simple plane 40 Hrs would be frustrating but with the big azz double slated flaps, option of variable drooping ailerons and LE slats as well as other aspects of my build and my propensity for thoroughness the airframe alone will take it's share of time to develop and document. I doubt I will get the slats right the first time.
Throwing in if the engine and prop were to be changed or altered which alone may take 20+lbs off the nose most all the previous testing would have been in vain.
So cool, I now understand I will be building expecting to have a Non-Certified power system.

skywagon8a said:

...My territory is restricted to the north by the Boston class B airspace so I centered the test area at Plymouth which is 10 miles south ....

Click to expand...

I know some other folks with similar issues who did the same thing.
Your 50-mile area does NOT have to be centered on your base airport.

And there is nothing that says it needs to be a 50 mile area. I usually try and give applicants an area where they can fly at cruise for an hour in a straight line. Sometimes it is a radius from some point, sometimes it is some polygon shape based on landmarks or airports.


Sent from my iPhone using Tapatalk

There is a reason that we still use 40 year old tractor parts. Old stuff is usually tougher.