Changing propeller: Major alteration?

I have decided to change my prop from a wooden to a metal Sensenich. This appears to fall under the "major alteration" category. Anyone know of the requirements for reporting to FSDO, test flight requirements, or just a self-imposed testing period, with logbook entries?

Thanks,

John

RV-4 flying for 8 happy years

If the Sensenich is certified for use on your engine (typically is) it is reportable but should not take you back into Phase 1 or at least if it does should be limited to say 5 hrs. Just call your FSDO ask for someone in maintenance and discuss. Get acknowledgement in email or writing.

Changing from wood to metal prop IS a major change. Primarily because it notably affects weight & balance.

You will need to go back into phase I for a minimum of 5 hours.
If your operating limitations were issued after around 1999, you should have a paragraph that allows you to put the airplane back into phase I yourself.
Be sure to check, as some op lims require you to notify the FSDO.

Check Limitations

As Mel said, check your limitations. I just did this today as I am going to test a different prop on the RV-10, so I called the FSDO and it was a very pleasant phone call. He initially thought I would have to come in so they could change my Limitations, but I politely explained how it should work and that I promised to do it right and make all of the appropriate entries and I was told "fly safe and have a merry Christmas'.
Couldn't have been easier.

Vic

I did this through Oakland FSDO recently. I agreed a 1 hour test schedule and proposed a route in/out of KHWD, which they accepted.

I sent them my proposal including weighing and adjusting the weight and balance schedule, inspection (torque, tracking etc), ground test and flight test schedules.

That was probably more than necessary, but it got accepted straight away.

My experience has been exactly like Vic's post. If changing from fixed pitch to constant speed, that requires more FSDO interaction. A change from one fixed pitch to another is easier. You probably need to notify, but should only need a logbook entry. On a certified plane, it usually would require a 337 form, which is a major repair or alteration, so I would consider it major. As Mel said, it depends on how your operating limitations read.

Every oplim I've ever read requires 5 hours regardless of what the change is. Even fixed pitch to fixed pitch. If you can get something in writing form FSDO that decreases or eliminates that requirement, that is an alternative. When we were racing we did Phase 1 for every pitch of propeller we were going to use, then documented them all as approved combos so we could quick change at Reno. All of them were 54" long Carbon props.

Ops specs

The ops specs guidance for new EAB certification changed earlier this year. I was the first EAB certification done by my DAR under the new guidance, early July 2015.
My DAR spent about two hours going over the paperwork with me. He was VERY SPECIFIC that under the new guidance any fixed pitch prop to any other fixed pitch IS NOT A MAJOR CHANGE and requires only a log book entry.
10 different FSDO or MIDO inspectors will probably have 10 different opinions on this subject.

He was mistaken or you misunderstood.

jrs14855 said:

The ops specs guidance for new EAB certification changed earlier this year. I was the first EAB certification done by my DAR under the new guidance, early July 2015.
My DAR spent about two hours going over the paperwork with me. He was VERY SPECIFIC that under the new guidance any fixed pitch prop to any other fixed pitch IS NOT A MAJOR CHANGE and requires only a log book entry.
10 different FSDO or MIDO inspectors will probably have 10 different opinions on this subject.

Click to expand...

The changes came about in May of this year. I spent weeks corresponding with the FAA over the changes. We finally got most (I think) of the errors ironed out. I've done 38 certifications to the new order.

The paragraph concerning major changes did not change from the old op lims. The wording is exactly the same as it was before. Any change that substantially changes weight & balance is still considered to be major and requires returning to phase I.
Changing a F/P to or from a controllable prop also requires a new 8130-6. This is not required for F/P to F/P. Maybe this is what he was talking about.

"After incorporating a major change as described in 21.93, the aircraft owner is required to reestablish compliance with 91.319......."
91.93(a) states that (paraphrasing) a minor change is one that has no appreciable effect on weight & balance, structural strength, etc.....It goes on to state that any change that does not qualify as minor is considered to be major.

Mel said:

The changes came about in May of this year. I spent weeks corresponding with the FAA over the changes. We finally got most (I think) of the errors ironed out. I've done 38 certifications to the new order.

The paragraph concerning major changes did not change from the old op lims. The wording is exactly the same as it was before. Any change that substantially changes weight & balance is still considered to be major and requires returning to phase I.
Changing a F/P to or from a controllable prop also requires a new 8130-6. This is not required for F/P to F/P. Maybe this is what he was talking about.

"After incorporating a major change as described in 21.93, the aircraft owner is required to reestablish compliance with 91.319......."
91.93(a) states that (paraphrasing) a minor change is one that has no appreciable effect on weight & balance, structural strength, etc.....It goes on to state that any change that does not qualify as minor is considered to be major.

Click to expand...

Mel, I fully agree that ANY prop change is a major and that phase 1 must be done. props are changed to change performance and that is one of the functions of phase 1, to document performance.

however, playing devils advocate here, what constitutes "appreciable"? if you change from from one wood fixed pitch to another brand and the difference is 2 oz, does that constitute "appreciable". has the FAA given any sort of guidance on that?

bob burns
N82RB RV-4

however, playing devils advocate here, what constitutes "appreciable"? if you change from from one wood fixed pitch to another brand and the difference is 2 oz, does that constitute "appreciable". has the FAA given any sort of guidance on that?
bob burns
N82RB RV-4[/QUOTE]

Sometimes you just have to use common sense. Obviously 2 ounces won't make a difference. This was original started about going from wood to a metal prop. That IS a significant change.

AC 43.13-1B (Ch 10-2.c.) defines a negligible weight change as any change of one pound or less for an aircraft whose empty weight is less than 5,000 lbs.

If you change pitch dramatically enough to affect performance, then that too would be major.

So?

Mel, my stepson is a new A@P and just changed a customer's Sterba to a three bladed Catto on his -4.

Logbook entry needed...that's all?

Thanks,

Just a thought...

As many have discovered and posted here, many FSDO's interpret the rules differently. We can debate all day on whether or not they can. The reality is that everyone, including the DAR's has no choice except to FOLLOW the Order. That being said, a simple call to the appropriate FSDO in each case is probably the best course of action. I have found them to be easy to work with, especially when approached with a "here's what I am doing (i.e., changing a prop) and my Limitations say I should contact the FSDO for a major change. In this particular case I don't think it is major, but nonetheless I will be making the appropriate entries in the logbook, updating the W&B if needed, and test fly it without passengers to make sure there aren't any adverse changes in flight characteristics. If it is a major change, I propose a 5 hours test area within a particular area, and I will update all of the documentation appropriately".

Most inpsectors will respond with a "sounds like you know what you are doing,and thank you for the call, tell you to fly safely."

It's really not that difficult, and it keeps everyone happy.

And BTW, you'd be surprised how different props really do affect our airplanes differently. I know. I've tested a few of them on the same airframes and was surprised at the impact on Stall speeds for instance.


Vic

Appreciable W&B Change

Mel said:

Sometimes you just have to use common sense. Obviously 2 ounces won't make a difference. This was original started about going from wood to a metal prop. That IS a significant change.
If you change pitch dramatically enough to affect performance, then that too would be major.

Click to expand...

I would argue that changing from a wood to a metal FP prop results in a W&B change that's less than a typical high quality paint job. I don't know of anyone that would consider a paint job to be a major change though.

Skylor

skylor said:

I would argue that changing from a wood to a metal FP prop results in a W&B change that's less than a typical high quality paint job. I don't know of anyone that would consider a paint job to be a major change though.
Skylor

Click to expand...

And I would argue that a paint job IS indeed a major change. A new weight & balance is needed after paint. Paint will change your empty weight and C/G.

And BTW, to add to the earlier post; AC 43.13-1B (Ch 10-2.c.) defines a "negligible weight change" as any change of one pound or less for an aircraft whose empty weight is less than 5,000 lbs.

Besides all of the points (which of course are totally right on) already mentioned by Vic and Mel, is the point to keep in mind that W & B change is not the only factor.

The FAA considers any change that could effect the W & B, the reliability (this is the one that can be the most fuzzy to define IMHO), or performance/handling, to be a major change.

The actual text in FAR 21.93 (which E-AB operating limitations refer us too for the definition of a major change) is......

A ??minor change?? is one that has no appreciable
effect on the weight, balance,
structural strength, reliability, operational
characteristics, or other characteristics
affecting the airworthiness
of the product. All other changes are
??major changes?? (except as provided in
paragraph (b) of this section).

W & B - that is an easy one.

Structural strength - A bit more challenging, because few of us are engineers

Operational Characteristics (Performance/handling) - This one can be a bit more complicated...
So, you changed from one wood prop to one made by a different manufacturer and the pitch is only one inch courser than the one you previously had.... That doesn't mean a thing until you test it and prove that the climb performance is acceptable.... Many of the prop makers measure their pitch values in different ways. The pitch value from one does not necessarily match up to the pitch value from another.

Reliability - This one can be the most difficult of all because it is the one that has the widest latitude for personal opinion.
My opinion (and that of at least a couple FAA people I have worked with over the years) is that any configuration change to something related to an important flight function of the airplane (engine, flight controls, etc) is a major change.
So, if you switch from regular mags to P-mags - Major change.
Carb. to fuel injection - Major change
Even just installing a different induction airbox that you designed would be a major change because it could adversely influence engine performance / power output.

The thing to keep in mind is that none of these or any other changes will automatically effect W & B, Performance, and/or Reliability, but until that is proven (via some level of flight testing) it is unknown.

Regardless of whether you agree or disagree with the above, we still always have FAR 91.407 which reads......

?91.407 Operation after maintenance, preventive maintenance, rebuilding, or alteration.
(a) No person may operate any aircraft that has undergone maintenance, preventive maintenance, rebuilding, or alteration unless?

(1) It has been approved for return to service by a person authorized under ?43.7 of this chapter; and

(2) The maintenance record entry required by ?43.9 or ?43.11, as applicable, of this chapter has been made.

(b) No person may carry any person (other than crewmembers) in an aircraft that has been maintained, rebuilt, or altered in a manner that may have appreciably changed its flight characteristics or substantially affected its operation in flight until an appropriately rated pilot with at least a private pilot certificate flies the aircraft, makes an operational check of the maintenance performed or alteration made, and logs the flight in the aircraft records.

(c) The aircraft does not have to be flown as required by paragraph (b) of this section if, prior to flight, ground tests, inspection, or both show conclusively that the maintenance, preventive maintenance, rebuilding, or alteration has not appreciably changed the flight characteristics or substantially affected the flight operation of the aircraft.

rvbuilder2002 said:

Regardless of whether you agree or disagree with the above, we still always have FAR 91.407 which reads......

?91.407 Operation after maintenance, preventive maintenance, rebuilding, or alteration.
(a) No person may operate any aircraft that has undergone maintenance, preventive maintenance, rebuilding, or alteration unless?

(1) It has been approved for return to service by a person authorized under ?43.7 of this chapter; and

(2) The maintenance record entry required by ?43.9 or ?43.11, as applicable, of this chapter has been made.

Click to expand...

Citing this regulation confused me. So just out of curiosity. As ?43 does not apply to experimental airplanes I would read this that 91.407(a) does not require us to do anything as it refers to ?43 . Our operation limitations govern what needs to be logged and inspected by whom which in the case of a mayor alteration seem pretty clear.

Am I missing something?

Oliver

spatsch said:

Citing this regulation confused me. So just out of curiosity. As ?43 does not apply to experimental airplanes I would read this that 91.407(a) does not require us to do anything as it refers to ?43 . Our operation limitations govern what needs to be logged and inspected by whom which in the case of a mayor alteration seem pretty clear.

Am I missing something?

Oliver

Click to expand...

Sub part A refers to part 43, so I agree, that does not apply to E-AB, but sub part B & C don't so they still do apply. That is the portion I was posting it for... It is relavent to the discussion of flight testing before carrying passengers.