Repairs beyond SRM 2

[Supernova82]

Hi people,

My first question on this forum. I know/understand the actual requirement on the SRMs that if any damage goes beyond the limitations, the manufacturer requires to be consulted and the repair (if it applies) needs FAA approval, however I am trying to find on the FARs (43, 25, 121) or other regulations the actual statement that would say that.

It is not for an specific airplane, manufacturer or even civil authority, is just the general statement.

If anyone can help please

Thanks!

 

[rb1957]

as i understand it the SRM gives you approved repairs, so you don't have to substantiate them yourself (ie the engineering is "iaw SRM").

if you're outside the SRM then the repair needs engineering and cerftification via an RDA/RDC to support the design. this can be OEM support, or it can be your own engineering, or it can be a 3rd party. I doubt the FAA says "thou shalt go to the OEM (so they can make another bag of money out of their sale)".

Quando Omni Flunkus Moritati

 

[debodine]

It is my understanding (which could be flawed) that any repair to an aircraft to return it to service must be FAA approved. The purpose of tools such as an SRM is not to remove the need for an FAA approval, but to provide repairs that have already been FAA approved. Thus if you are applying a repair that has not already received FAA approval (such as would be found in an SRM) you still must obtain an FAA approval but you will have to use another method other than an SRM repair. Thus there is no need for an explicit statement outside of an SRM since ALL repairs must be FAA approved.

As far as consulting the manufacturer...I don't believe that is an explicitly stated requirement anywhere. What must occur is the repair must be in compliance with all pertinent FAA regulations. In our world (part 25 MRO and engineering firm) that usually means consulting the manufacturer because they have the original design data at their fingertips to perform tasks that we cannot perform or can only perform with overly constrictive conservatism such as Damage Tolerance Analysis for many areas of the aircraft. So we consult the manufacturer not because a FAR states we must, but because to obtain the data necessary to support our repair requires consultation because the necessary data exist no where else.

I hope this helps.

 

[Supernova82]

Thanks! I am Liaison engineer and i am trying to explain to some new liaison guys how extended the repairs on the SRM are and when do we need consultation (we are from manufacturing of new products, not maintenance), but the actual "why" popped up and was trying to look under the regulations if there was any specific mention, just to back up my answer..

 

[WKTaylor]

Each aircraft/model has a specific design configuration that must be maintained to be considered certified/airworthy.

Once that configuration has been altered, due to what ever cause [physical damage, corrosion, modification, equipment removal/addition, etc] then the airworthieness certification becomes invalid. Any of the following have to be accomplished...

Return to airworthy configuration by 100% parts/assembly replacement per existing MM & SRM data.

Return to airworthy configuration by repair to damaged structure and/or components per engineering approved data, parts, materials, fabrication and assembly data.

Engineering/FAA evaluation of, and approval of, modifications such that they become part of the airworthieness documentation [permanent or temporary] for that aircraft or type/model of that aircraft.

Revocation of existing certification and airworthieness ... and reversion to a "special" or experimental certification, etc...

Combinations of the above.

In the case of new aircraft production, all MRB actions affecting that aircraft become part of the certification "package" for that unique aircraft; or the data [changes] are formally incorporated on the engineering drawings for that S/N aircraft... and all others that may also be affected. "MRB and drawing incorporations" impies that both quality and engineering approva [company and FAA] must be granted for each and every case, effectively altering the aircraft certification "on-the-fly".

NOTE. Military aircraft certification follows parallel, but different tracks. See MIL-HDBK-514, MIL-HDBK-515, MIL-HDBK-516 and the JSSGs.

Note. Military aircraft, derived from civilian aircraft and follow a different certification track entirely... spanning FAA amnd military certification procedures.

OK, I know I have forgotton something... but gotta go...



Regards, Wil Taylor

Trust - But Verify!

We believe to be true what we prefer to be true.

For those who believe, no proof is required; for those who cannot believe, no proof is possible.

 

[cjohnso0]

I come from Turbine Engine Repair as a Repair Development Engineer. I work in aftermarked, not OEM, so we deal with this all day every day. 14 CFR 43.13 actually spells out the requirements for maintenance etc...

"Sec. 43.13

Performance rules (general).

(a) Each person performing maintenance, alteration, or preventive maintenance on an aircraft, engine, propeller, or appliance shall use the methods, techniques, and practices prescribed in the current manufacturer's maintenance manual or Instructions for Continued Airworthiness prepared by its manufacturer, or other methods, techniques, and practices acceptable to the Administrator..."

Basically, you can use OEM repair data, or any other data approved by the FAA. We typically approve data on form 8110-3, you can also use form 337 for field approvals, though I have no experience with that. Another method would be STC's, but I think they are mostly for alterations.

You can also check out AC 43-13, and probably some others, for other repair methods that are FAA approved.

 

[rb1957]

yes, doesn't that "just" say that repairs need to use approved data. this can be SRM or new engineering that is substantiated. all repairs need to be approved (RDA, RDC, 8110, 337, ...) and the approval will point to the supporting data (either SRM or new negineering).

Quando Omni Flunkus Moritati

 

[berkshire]

The key word is "approved data" I have had FAA inspectors question whether or not data is "approved " on a repair schedule sent back from the manufacturer of the aircraft( OEM) . So I feel that sometimes this can be subject to the whims of the FAA unless you have all of your ducks in a row .
B.E.

 

[rb1957]

i'd've thought that a repair design from an OEM was "approved", but then i'm not an FAA inspector !?

Quando Omni Flunkus Moritati

 

[kontiki99]

I don't work structures, but do know that operators certified under different parts of the FARs have different levels of approval authority.

What certifications you hold really determines the limits of your approval authority.

I can't tell you how many times a 3rd party vendor has told us what we can't do as an operator simply because they can't as a parts manufacturer.



In theory, there is no difference between theory and practice; experience suggests that in practice, there is.

 

[debodine]

rb1957:

If I may offer a point of clarification, your statement is correct that a repair from an OEM arrives as FAA approved, but I wanted to change the focus a bit. It does not arrive FAA approved because the OEM designed the repair...it arrives FAA approved because after the OEM created the repair an appropriately qualified FAA ACO engineer or an appropriately qualified DER reviewed the data, found compliance to the applicable FAR requirements and approved the repair. If the FAA approval was not obtained, the repair should not be sent for you to use.

Just wanted to be clear on why you are correct that those OEM repairs show up already FAA approved. )

 

[debodine]

berkshire:

I feel your pain. On occasion, we have also had FAA inspectors question the OEM supplied data that already carried FAA approval. The bottom line is any FAA inspector can challenge FAA approved data if they believe it needs to be challenged. If the FAA ACO engineer or DER who approved the data did their homework to make sure the data creator properly substantiated everything in compliance with all applicable regulations, then the FAA approval will probably stand unless the complaining FAA inspector has chosen to play politics.

I remember some years back an STC was issued for a cargo door which had been fully reviewed and approved through the STC process and installed on some aircraft. It was later reviewed again and found deficient by the FAA and the STC was rescinded. That is unusual but a possibility with any FAA approval. If an FAA approval is believed to be deficient, it can be challenged and if the challenge is successful, rescinded at the direction of the FAA.

 

[rb1957]

i wish the FAA would apply that ruling to the DT component of repairs/STCs/etc !

instead they foistered Part 26 on us.

Quando Omni Flunkus Moritati

 

[debodine]

Well said, rb1957.

kontiki99:

I do understand your point very well. Where we typically see the conflict is where the operator has changed the aircraft and approved it under FAR 121.379(b). This FAR allows part 121 operators to return an aircraft to service under their operating authority, except that the operator must use FAA approved data for major repairs and major alterations. Thus minor repairs and minor alterations do not require data that is FAA approved.

The problem occurs when we are asked to create a major alteration (normally via STC under our ODA) and include these previous operator approved changes. However, under our FAA region the changes are judged to be major repairs and/or major alterations. This can happen between different FAA regions, or sometimes it is just the operator's interpretation of what they could approve as minor twenty years ago differs with the current understanding of the regulations today.

 

[kontiki99]

debodine

I primarily work avionics. We might get the rights to use an STC as part of an LRU purchase agreement.

There is typically a lot of variation at terminal blocks and in connectors on 20 & 30 year old airplanes. The LRU OEM cannot approve the minor aircraft wiring connection changes needed to make the correct connections when these variations are found.

If there happened to be a lot of older 3rd party mods on the aircraft, documentation showing exactly how and where wiring was installed may not even exist. I've see cases where lease return paperwork packages did not include previous airline operator wiring diagram supplements.

The resulting STC implementation is electrically correct, but the connection points may be all over the map. It all got harder with EWIS rules and SFAR88 wiring separation rules.

In theory, there is no difference between theory and practice; experience suggests that in practice, there is.

 

[debodine]

kontiki99:

Wow do I empathize with your point! (My first 30 years were in electrical, only the last 10 years have been interiors) I recall very well the variations at connector blocks that you describe. Although I still thoroughly enjoy most everything connected with electrical engineering on aircraft I don't miss having to sort out terminal block issues! More power to you for having the patience to get it done.

I imagine it is also frustrating when you try to create the wiring diagrams to document your design, as you know for sure what YOU did, but as you explained you may not have the documentation available to clearly show what was done before you created your changes.

 

[Sparweb]

I think the discussion has forgotten the original question. The OP is asking for the regulation that defines major and/or minor alterations, and the associated data required to substantiate and approve them. This is usually linked to the maintenance function of operators and MRO's, meaning that work carried out on an aircraft must be done in accordance with approved data (approved either by FAA/EASA/Transport Canada, or their representatives in the OEM). The OP didn't specify their jurisdiction, so might as well assume USA. In that case you need to look at FAR part 43. From there you can quote chapter and verse as you like it:

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgFAR.nsf/MainFrame?OpenFrameSet

The reason for this is that ONLY a licensed maintenance person is authorized to sign a maintenance logbook entry. Every change to the aircraft has to pass through that log, per FAR 43.5 (supposed to in theory, different parts of the world see this differently but let's just stick to the western world for now) meaning that the licensed mechanic has backed up the signature with approved data, or some other source of data acceptable "to the administrator (FAA)", such as Advisory Circular 43.13.

From there, drill down through the Appendices A and B, to impress your colleagues with the jargon and legalese.

PS you will not find any requirement in there to get the data from the OEM. Unfortunately, it branches out rather quickly from there because you now have to investigate a number of other regulatory requirements for repair stations, personnel licensing, airworthiness standards, and certification procedures for "Aeronautical Products" and so on...

The FAA gives course on the subject, by the way.

STF

 

[berkshire]

Well just to add fuel to this fire, most of the aircraft I work on fall under part 23 of the FAR's, which the FAA in their wisdom are now completely revising.It is going to be interesting to see how this plays out.
B.E.

 

[kontiki99]

In every approval substantiation I write, I try to address 2 subjects.

1 - How what I'm approving falls within my approval authority.

2 - What is the technical reasoning that makes it OK.

In order to answer the first, you must know the limits of the authority granted to you by the operating certificate you are working under.

I work for a certified part 121 operator.

We are required by law to follow the internal FAA published process for making that Major/Minor determination.
That internally published process was the basis for the FAA to approve our operation under that certificate.

In theory, there is no difference between theory and practice; experience suggests that in practice, there is.

 

[berkshire]

I do not want to get this discussion too far off onto a tangent, but this is part of the discussion on the part 23 rewrite.
regarding approvals for equipment installed on aircraft.
"" General Aviation Manufacturers Association President Pete Bunce said Wednesday at Aero in Friedrichshafen that the international regulatory community has seen the light on revising certification rules and efforts to overhaul Part 23 and its international equivalents are gaining momentum. "When you can go and put modern equipment into an amateur-built aircraft and have it perform just tremendously well, but then it costs ten times as much to be able to put that into a certified airplane … wait a second, our regulatory process is defeating the purpose for which it was set up, and that's to enhance safety. We, as an industry, need to change that."
How many times have you hit " Wait a minute , you cannot put that in there, it's not approved."" ?

B.E.