What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

New Lycoming compression test requirement before first flight

ssturges

Active Member
I was going through AC90-116 ( Section 9.b) - additional Pilot Program for Phase 1 flight. It states a requirement for a compression test before the first flight. Are people doing this and DAR's requiring this on a brand new Lycoming? I have never seen this talked about.

Thanks,

Steve
 
A condition inspection must be performed prior to first flight (and DAR sign-off), which would entail a compression check.
 
Correct-ish

A condition inspection must be performed prior to first flight (and DAR sign-off), which would entail a compression check.

This is correct-ish. The newer (last ~2 years) boilerplate operation limitations that the DARs are using has a statement that "No person may operate this aircraft unless within the preceding 12 calendar months it has had a condition inspection in accordance with the scope and detail of 14 CFR part 43, Appendix D..."

14 CFR Part 43, Appendix D, (d)(3) indicates you must do a compression test.

So, IF your operating limitations say the above, then in order to conduct the first flight, you have to complete and sign off on a condition inspection. As part of that condition inspection, yes, you must do a compression test.
 
compression

I've seen inspection instructions which just specify a prop pull-through to check for a weak cylinder. 14 CFR Part 43, Appendix D doesn't seem to specify the type of compression test.

Am I missing something?
 
Maybe...

I suppose "Well, I pulled it through by hand, and it feels ok to me," might be a "compression check." But Lycoming has SI-1191 which basically says you have to use a differential compression check.

Whenever I encounter situations like this, I picture the worst outcome, where an NTSB investigator is asking me questions about what lead up to the incident, and I'd prefer to give the "right" answer. So before my first flight, and at every annual, I do a compression test using a differential compression tester, and I record those values in my engine logbook.

If you can answer that with a straight face by saying you pulled the prop through, that's entirely up to you.
 
This is correct-ish. The newer (last ~2 years) boilerplate operation limitations that the DARs are using has a statement that "No person may operate this aircraft unless within the preceding 12 calendar months it has had a condition inspection in accordance with the scope and detail of 14 CFR part 43, Appendix D..."

14 CFR Part 43, Appendix D, (d)(3) indicates you must do a compression test.

So, IF your operating limitations say the above, then in order to conduct the first flight, you have to complete and sign off on a condition inspection. As part of that condition inspection, yes, you must do a compression test.

This has been a standard part of operating limitations for many decades.

It has only been in the last few years that CFR 8130.2 was updated to have all of the different limitation listed out in a chart/Appendix, but for a long time it has been a standard requirement for E-AB
 
Kind of funny if this is really true, I can't sign off on the pre first flight conditional as I don't have a repairman's certificate yet as it new plane.
 
Also, aren't compression checks really supposed to be done, if possible, with the engine hot? As in, go fly for an hour, then land, decowl and do the test?

Would Lycoming's test stand reports for a new engine suffice? Seems silly, although not difficult, to do a compression check on a brand new engine (while cold, of course).
 
A new or overhauled engine pre break in is not likely to pass a compression test since the rings aren?t seated. Unless Lycoming specifies a different limit before the engine has been run.

I won?t even enter the foray on the condition inspection requirement.
 
Also, aren't compression checks really supposed to be done, if possible, with the engine hot? As in, go fly for an hour, then land, decowl and do the test?

Would Lycoming's test stand reports for a new engine suffice? Seems silly, although not difficult, to do a compression check on a brand new engine (while cold, of course).

This was my thought, I will see if it was provided in the engine documentation when I get to hanger.
 
Not True...

Kind of funny if this is really true, I can't sign off on the pre first flight condition inspection as I don't have a repairman's certificate yet as it new plane.

FAA Order 8130.2j says that you, as the owner may/must sign off this initial inspection:

(3) Verify that aircraft records include a completed statement from the owner that the aircraft has been inspected per part 43, appendix D, or other approved programs, and was found to be in a condition for safe operation. The inspection will help identify any errors made during construction of the aircraft. This statement will support the owner’s inspection and airworthiness statement in block III of FAA Form 8130-6.
Note: There is no requirement for a certificated mechanic to sign off on the inspection. The builder’s signature on FAA Form 8130-6, block III, attests to the airworthiness of the aircraft.
 
Continental engines?

It's my distant recollection that Continental engines don't have compression as a test specification... Not that many RVs have Continental engines...
 
Back
Top