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LOA Needed for Remote Sensor Mounting?


S3flyer

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I understand that remote mounting of the oil pressure sensor is supported by Rotax and is recommended by Dynon. Is this sufficient or do I need an LOA from my Sting S3 manufacturer? My manual explicitly defers to Rotax for engine maintenance, installation, etc.

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My friend's CTLS started showing low oil pressure readings. At his last 100 hour, he had the remote pressure kit installed. His reading came up 15 psi and seem to be rock steady. Made a believer out of me - I'll have the kit installed on my CTSW next inspection.

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Hi Dave,

 

You can move the sender for the remote mount without the LOA

 

I get confused by when an LOA is needed and when not (I personally have an experimental so don't get too concerned on my own behalf). The airframe manufacturer is going to define the standard, right?

 

To me, this is a "nose under the tent" deal. We know that a kit built ILSA must meet the manufacturer's specs and equipment lit. If you want to substitute a radio you need an LOA. If you want to add a fuel shut off, you need an LOA or you will not get your ELSA passed for an airworthiness certificate.

 

If that is the case, what is the difference between that and putting in a new landing light or battery without an LOA? How about putting on larger tires?

 

In each case, I'm talking about cases where the manufactuer has not put out a blanket LOA.

 

Sometimes I get the feeling that the culture is arising that we can ignore LOA's when it is convenient to do so.

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Sometimes I get the feeling that the culture is arising that we can ignore LOA's when it is convenient to do so.

 

It seems like well respected shops are doing it as well.

 

I know of two Sky Arrows that had batteries installed that were not the one listed in the manual and without any LOA that I know of.

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We aren't changing any equipment. We are not altering any flight characteristics. All the parts are the same except we are just moving it. Most LSA companies say to follow all the Rotax rules, regs, requirements and recommendations some where in their manuals. If we were changing a piece of equipment or it was some how off the beaten path and not recommended by Rotax I would say it needed an LOA, but for this remote mount I don't believe it does and I doubt anyone would give you grief over it especially when you can show printed service information from Rotax.

Because of poor wording in way too many LSA manuals and loose reg interpretations I'm sure some changes might walk a thin line. Many times the MFG knows less about the regs than some of us in the field.

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Ok, so for E-LSA, you never need an LOA. For minor alterations, like changing the battery, you or your mechanic just need to note the change in your logs. Major alterations require a new FAA inspection and will get assigned at least a 5hr Phase 1 to continue airworthiness The plane has to be fully kit or S-LSA manufacturer compliant when built (or transitioned to E). So I can't go E-LSA with preexisting mods, like a Li battery even though I can readily swap it out as soon as I am E-LSA. Now for S-LSA, you need to follow the specifics in your AOI, which points you to the Rotax manuals so the specifics in there as well. Where they are not specific, you have leeway.

So for specific S-LSA cases:

  1. Battery: FD specifies a specific Hawker battery, and later blanket LOA for the Odyssey PC310. You cannot swap out for the Shorai battery without an LOA.
  2. Capacitor: Rotax is not specific so anything above 25V rated and 22,000uF is compliant. No LOA needed
  3. Tires: FD is actually pretty specific with exact part numbers for Sava and Air-Trac tires in either 4.00-6 or 6.00-6. Not sure if there is even an LOA for the Desser Aero classics and such but technically there should be. Roger likely knows. But the FAA gives wide allowance for any pilot to change tires if they are compatible (cannot change the weight/balance in particular) so it is extremely unlikely to get dinged for this one. Changing the size of tires is a significant change though.
  4. Landing Light: FD is somewhat specific, calling for a generic 100W halogen. But again, the FAA gives wide leeway for users can change any bulb they like (under part 43 app A preventative maintenance like for the tires) http://www.flightsimaviation.com/data/FARS/part_43-appA.html However, if you are modifying a fixture or adding wires or switches to your panel, need an LOA. One big problem with the excellent HID bulbs, for instance, is you have to wire in a ballast unit and bolt it somewhere. Need an LOA.
  5. For the remote sensor, a qualified mechanic is generally permitted to alter routing of any sort of line to/from the engine. Should not require an LOA if it uses an approved sensor.

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For anyone having any issues with the oil pressure sending unit I would encourage them to switch to the remote mount. After replacing three senders in a little over a year I had Roger install the remote unit when he did the hose change. What a difference, more than 15 months now and not one problem and readings are rock steady.

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To all,

The rule is specific (FAR 91.327). ANY alteration (does not matter if major or minor) must have mfg approval. I realilze that this is of course, subject to interpretation, and can be taken to an extreme, but I might offer a couple of reasons for this requirement.

 

Since the aircraft manufacturer is responsible for the continued airworthiness requirements of their SLSA product, and not the FAA, they must always be aware of the aircraft configuration. To say it another way, SLSA manufacturers are required by certification rule to monitor for and correct unsafe conditions that may arise with their products. They must do this through the Safety Directive (not service bulletin, service letter, alert letter, or other document) system. Operators are required to comply with applicable Safety Directives via 91.327. If the mfg is not aware of configuration changes to a specific aircraft, they may not be in a position to accurately monitor them for unsafe conditions. Further more, since manufacturers must provide, and maintenance must follow mfg inspection procedures, any alteration could potentially effect future inspection requirements. If the MFG is not aware of, or has not authorized the alteration, they are not in a position to provide these additional inspection procedures.

Sometimes, people want to apply there own expertise, and determine that an alteration is so minute, that no mfg approval is needed. This is not the owner/maintenance provider's call, and can potentially put the MFG in a position where they cannot properly meet their continued airworthiness requirements. This could possibly lead to an unsafe condition developing and going undetected.

 

 

 

Doug Hereford

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FD has had this oil remote mod approved since April 2008. The LOA #080404. Many of these small mod issues can be found to be approved or not approved by looking in the aircraft's manuals, LOA's on line or by just calling them. I'm changing a prop on a Tecnam to a Sensenich and all it took was a phone call to get an LOA.

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To all,

The rule is specific (FAR 91.327). ANY alteration (does not matter if major or minor) must have mfg approval. I realilze that this is of course, subject to interpretation, and can be taken to an extreme, but I might offer a couple of reasons for this requirement.

 

Since the aircraft manufacturer is responsible for the continued airworthiness requirements of their SLSA product, and not the FAA, they must always be aware of the aircraft configuration. To say it another way, SLSA manufacturers are required by certification rule to monitor for and correct unsafe conditions that may arise with their products. They must do this through the Safety Directive (not service bulletin, service letter, alert letter, or other document) system. Operators are required to comply with applicable Safety Directives via 91.327. If the mfg is not aware of configuration changes to a specific aircraft, they may not be in a position to accurately monitor them for unsafe conditions. Further more, since manufacturers must provide, and maintenance must follow mfg inspection procedures, any alteration could potentially effect future inspection requirements. If the MFG is not aware of, or has not authorized the alteration, they are not in a position to provide these additional inspection procedures.

Sometimes, people want to apply there own expertise, and determine that an alteration is so minute, that no mfg approval is needed. This is not the owner/maintenance provider's call, and can potentially put the MFG in a position where they cannot properly meet their continued airworthiness requirements. This could possibly lead to an unsafe condition developing and going undetected.

 

Do you really think that every tie-wrap, washer, weather stripping etc all needs to be MFR approved? That would be a much higher burden than even is applied to normal GA. The FAA does not bother to define Alteration but they do lay out their rules for alterations and repair in 43.13 http://www.ecfr.gov/cgi-bin/text-idx?c=ecfr&sid=&rgn=div8&view=text&node=14:1.0.1.3.21.0.363.10&idno=14 Basically it says to follow the manufacturer instructions in a) and in B) "use materials of such a quality, that the condition of the aircraft, airframe, aircraft engine, propeller, or appliance worked on will be at least equal to its original or properly altered condition" You can call FD all you want to get an LOA for your touch-up paint, etc but I suspect they will tire of it after awhile. If you do" work in accordance with accepted industry practices." using "quality" materials, then you are completely FAA compliant.

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I was surprised not to find "Alterations" defined in Part 1, since left undefined it is pretty vague.

 

Is swapping a better battery for the factory-specified one an "Alteration"?

 

Lacking a formal definition, I'd say it was - the plane has been altered to the extent it has a different battery, if nothing else.

 

Would be nice to have case law on this, to be safe.

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That is true, and yes they should have defined it. What you really have is a long history of lack of case law for these small changes. Because the FAA has never bothered pursuing little things like possibly irregular minor alterations. However, in your example this is a definite violation because FD documentation is very specific about batteries plus it is more than a 1lb change in weight (also not in the regs, but the FAA examiner said that is their threshold for when you should redo the W&B ) . FD are not specific about light bulbs so you can use any decent, compatible one and still be fully compliant with their manuals. The key is that if there is some important specification about the part or how it needs to be mounted, whatever, then it is supposed to be thusly restricted in the documents.

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Understood.

 

I think I mentioned before that my Sky Arrow calls for a specific FIAMM battery, not available in his country last I checked, and more than $300 from Italy after shipping.

 

A well respected shop installed a Powersonic. AFAIK, no LOA.

 

I'm Experimental now, so I went with an Odyssey - more power, sealed and less than half the price. Several pounds heavier and renders the battery vent tubing superfluous. Of course I recalculated my W&B. But I also have to consider the battery case support hardware - is it up to the extra weight? The battery is a tad smaller, so is the rubber cushioning I added airworthy? The terminals are flush mounted, opening up the possibility of chafing on the hold-down bracket - are the steps I took to prevent that adequate?

 

My signature in the logbook indicates I think the answer to each of those is "yes". I'm free to "experiment", and I have. But one can see that a manufacturer might be very hesitant to carte blanche authorize deviations without some sort of testing.

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And well they should. Batteries are not really so simple to spec. And why should the OEM spend time figuring out if a new battery is fine when it ultimately earns them $0 extra. FD did it for the Odyssey battery because the Hawker was nearly impossible to get here in the US, so it was a big customer problem. But they have no incentive to qualify the Shorai LiFePO4 battery. I doubt they would give an LOA for it since they won't want to spend the time studying the specs and qualifying it.

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FD at one time had an option for a larger Odyssey battery. Believe it is the PC545? If this is still offered by FD, woudn't this be an option for retrofitting?

 

Safety officer, prior to your post, I looked at the forum's LOA page but didn't see the LOA for remote mounting the oil sender. Could you please incude LOA #080404 in our LOA list if it is not there? I also looked at FD website for this and cound't find it. Is there a way I can download this LOA? Thanks.

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Chanik,

I guess my direct answer is yes, I would expect mfg approval for fastener substitutions, additions or omitions. Why would one do this anyway?

At any rate, the mfg approval is a part of the SLSA system we have. If it isn't working, maybe it needs to be changed. I for one would not worry the least bit about bugging the mfg everytime I needed approval. This is part of their job. They were more than happy to take your money. They are basically getting free R&D.

Paint touch up should be a repair mx or possibly preventive mx, and would not require alteration approval, just a procedure.

As for the performance rule 43.13. That rule gives no relief from mfg approvals to alter SLSA.

Doug Hereford

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Many LOA's now cost $150. Some MFG are up to $200. Too many LOA request have taken too much of their time and some need research for structural or flight characteristic performance. For simple, researched and well documented submit talks you may get them passed easily and free. Many owners don't do this research and documentation and leave it to the MFG so they now have a charge for their time and extra work.

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Chanik,

I guess my direct answer is yes, I would expect mfg approval for fastener substitutions, additions or omitions. Why would one do this anyway?

Partly because you can't help it. You don't know the exact manufacturer and part numbers of all the incidental hardware. Do you buy your flat washers directly from their Ukrainian maker? I've seen customs stickers

At any rate, the mfg approval is a part of the SLSA system we have. If it isn't working, maybe it needs to be changed. I for one would not worry the least bit about bugging the mfg everytime I needed approval. This is part of their job. They were more than happy to take your money. They are basically getting free R&D.

Paint touch up should be a repair mx or possibly preventive mx, and would not require alteration approval, just a procedure.

As for the performance rule 43.13. That rule gives no relief from mfg approvals to alter SLSA.

Doug Hereford

It could use to be clarified, especially the FAA's vague wording about Alteration. But they don't chase anything that doesn't clearly conflict with OEM documentation and 43.13 lays out what they consider appropriate so it does, in fact, give a legal basis for making minor changes. The legal precedent here is more important than their fuzzy wording. In any event, having had GA, home-built and now and S-LSA to E-LSA airplanes, I can tell you that people generally get too tied up with what the big, bad FAA might do. They are reasonable, if still slow and bureaucratic. BTW, paint is indeed considered a critical 'part' or material and FD is quite specific about how, and with what, to clean, prep and repaint using specific part numbers for the 2-part urethane (Woeropur lacquer white 77547 W750 /. ) etc. A 2mm nick, no prob, but repaint the whole plane with Kragen touch up paint and I think the FAA and FD might have issues.

In summary, just follow the FAA advisory circular which states "Don't sweat the petty stuff and don't pet the sweaty stuff." Can't recall the exact number for that one.

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In summary, just follow the FAA advisory circular which states "Don't sweat the petty stuff and don't pet the sweaty stuff." Can't recall the exact number for that one.

A concept I would like to live with but one that leaves it open to the FSDO inspector's interpreation as to what we in the SLSA world need to comply with. The quote comes up in a George Carlin context, and maybe we'd all like to think of the FAA in that light, but it's not likely to happen. I didn't see any maintenance AC's that looked like they would provide any more help.

Sadly, we remain in either a scenario of absolute, sometimes foolish, compliance or personal choices which are subject to objection by mechaincs, the FAA, a prosopective buyer, the warranty and insurance people and you name it.

If one goes the relaxed route, then who is the guru who's word works? What mechanic is really willing to sign off on what you want or he wants or the previous owner wanted?

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Chanik,

43.13 is not an approval for alterations. It merely gives requirements for performing alterations (and mx) after approval is obtained. Again, no relief from mfg alteration approval requirement.

I understand what you are saying with regard to procuring parts. I just don't see any way around it if the manufacturer is specific about a P/N. If they allow for the use of parts that merely meet a certain standard, then one has options. Same goes for paint systems, and yes I understand that paint is a critical component of the aircraft (Re-painting would not normally be an alteration however).

 

Maybe FD needs to include some references to standard hardware in their IPC, or provide hardware kits with their aircraft. Same for other hard to get stuff.

What drew me into this conversation was another's post about the possibility that mfg approval is possibly being looked at with some disregard when convenient (or inconvenient). I agree that this could easily happen, and mfg should want to do their part to help prevent it (good business).

 

I don't think compliance should be sought because one is afraid of the "big bad" FAA. Sometimes there can be bigger reasons for the rules, than meet the eye, and if those reasons become known, compliance starts to makes sense. It is often easy to argue big buracracy, but I just don't see it here. (I don't know that A.C number either).

 

$150 to $200 seems cheap for alteration approval. As most know, approved data in the Standard airworthiness world can approach ten times that in many cases.

 

Doug Hereford

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A concept I would like to live with but one that leaves it open to the FSDO inspector's interpreation as to what we in the SLSA world need to comply with. The quote comes up in a George Carlin context, and maybe we'd all like to think of the FAA in that light, but it's not likely to happen. I didn't see any maintenance AC's that looked like they would provide any more help.

Sadly, we remain in either a scenario of absolute, sometimes foolish, compliance or personal choices which are subject to objection by mechaincs, the FAA, a prosopective buyer, the warranty and insurance people and you name it.

If one goes the relaxed route, then who is the guru who's word works? What mechanic is really willing to sign off on what you want or he wants or the previous owner wanted?

Sure, but there are many mechanics willing to cavalierly pencil-whip annuals and sign off all sorts of stuff. It's a big, and well documented, problem with older twins and such since you can buy an old Queen-Air for <1/2 what it costs just to overhaul the engines. There is no substitute for making sure your mechanic does thorough, professional work. Because the FAA IS quite tolerant of letting mechanics use their judgement so long as it is not Major and they are not in open conflict with OEM manuals. You can take 43.13 and just claim it isn't an Alteration (since they don't define the term) if nothing is substantially altered. It doesn't matter because the FAA has an easily shown implicit policy of tolerating that sort of work. So they aren't going to chase you. My close friend runs Victory Aero and we've talked quite a bit about how he handles slip-shod work from other A&P's. as well as sketchy FAA oversight.

It is often a good idea to seek LOAs even if you could get away without them. But its a judgement call. No regulation will ultimately change that.

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