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ME 406 ELT Battery

RFSchaller

Well Known Member
Well, cheap me hoped to go to Batteries Plus and get my ELT Battery replaced at half price like I did on my PLB, but it looks like ARTEX found a really unique battery that is made out of unobtainiim (symbol UN).

The cheapest I could source a replacement was Aircraft Spruce at $173. Amazon was a little over $200.

My point: it pays to shop around!
 
Oh, and in case you don't already know, there is a $50 hazmat fee in addition to the shipping charges on an ELT bat. :(
 
I just had my ME-406 battery for my RV12 replaced at Tiffin Aire at Seneca County airport, 16G, Ohio. They were fast, polite, helpful, competent and it cost $187.73. I am satisfied.
 
(google ULTRALIFE High RATE)
11-14548.jpg


Pilot Shop sells them for about $25 each and you will need two. Also other battery vendors stock them. I'm getting ready to replace mine.

Of coarse you will need to remove the battery tray from the ELT. You'll need a very small screw driver to slide the blue plastic catch latch that hold the ribbon cable connector, and slide it off. Be sure to take a few pictures of how it is assembled, and they did glue the battery to the tray with white bathroom shower RTV, so you'll need to clean it up.

It should be a one hour job to replace just the batteries.

The batteries are ULTRALIFE High RATE. The Cell dates on mine are June 2010, with an expiration date of November 2016 (by Artex). The Ultralife website indicates they have up to 10 years shelf life.
Here is a picture after cleaning up the RTV used to hold the batteries. I've found them on line for as little as $15 each. I'll be ordering mine later tonight online.
http://www.538.eaachapter.org/apps/photos/photo?photoid=203972892
photo


Part No U10013, U10014, U10015, U10016
NSN 6135-01-554-3803 (U10014 only)
Voltage Range 1.5 to 3.3V
Average Voltage 3.0V
Nominal Capacity 11.1Ah @ 250mA to 2.0V @ 23°C
Max. Discharge 3.3A continuous
Pulse Capability Up to 7.0A
Varies according to pulse characteristics, temperature, cell history and the application. Consult Ultralife.

PTC U10014 and U10016 have PTC (re-settable fuse)
U10013 and U10015 do NOT
Weight 115g
Operating Temperature -40°C to 72°C
Storage Temperature -40°C to 95°C
Exterior/Housing Hermetic Ni-plated steel can with Mylar sleeve
Terminals/Connector Flat Ni-plated +/- End Caps: U10013 and U10014
Flat Ni-plated +/- End Caps with Nickel Tabs: U10015 and U10016
Safety UL component recognized
Material Safety Datasheet - MSDS023
Safety Guide UBM-5135
Transportation Class 9 - U.S. and International (see note)
Note A complete description of transportation regulations, lithium weights and transportation classifications is available on the Ultralife website.
 
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Chris - I would advise you do some research on this topic. The ONLY battery which can be used as a replacement battery in your ELT is the battery manufactured and supplied by the ELT manufacturer. The battery makes up part of the TSO certification. Even though you are in an Experimental aircraft, you MUST use a TSO'd ELT. There is no room for interpretation on this point. Use something other than the manufacturer-approved battery in your 406MHz ELT and you do not have a TSO'd ELT, therefore you are in contravention of the FARs. Very simple, very clear-cut, and not open to interpretation, as has been discussed here at length previously.

Again, to put a fine point on it. NO HOMEBUILT BATTERY PACKS for 406MHz ELTs. Period.
 
As Carl so accurately observed, my choice of words was quite intentional. Alkaline D-cells just don't do well when asked to put out the large current spike required for the high transmission power of the 406MHz data burst. As a result there are no 406MHz ELTs which are certified for use with over-the-counter alkaline D-cells.

While it may not be immediately obvious, ELT manufacturers aren't getting super-rich selling ELT's. They rely on the sales of battery packs to provide some on-going income, without which the sale of 406MHz ELT's in the sub-$1000 range would be totally unsustainable.
 
So, is the Ultralife U10014 the one we need?

I see that there are quite a few "D" cells offered
U10013, U10014, U10015, U10016, etc. Confusing!

Tom
 
The term "airworthy" is interesting. We do not certify our experimental aircraft to be airworthy at annual because there is no type certificate we comply with. We certify they are in a condition for safe operation. We can fly with avionics in IMC even if they aren't TSO'd. Why would you conclude the ELT must be TSO'd?
 
The term "airworthy" is interesting. We do not certify our experimental aircraft to be airworthy at annual because there is no type certificate we comply with. We certify they are in a condition for safe operation. We can fly with avionics in IMC even if they aren't TSO'd. Why would you conclude the ELT must be TSO'd?

Ummm... not to be too argumentative, but we ARE required to use some TSO'd avionics when we fly IFR, or to have verifiable performance in compliance with the TSO. As an example (and, regrettably, a darned expensive one) nobody is flying with a non-TSO'd GPS navigator to do LPV approaches because very, very few people have the capacity to design a device to the same standard as required by the TSO AND demonstrate that it meets the technical and performance standards set out in the TSO.

With respect to ELT's, I won't do all the leg work for you but rather will suggest you peruse some earlier discussions on this topic wherein you will find references to the exact FAR which mandates the carriage of a TSO approved ELT. It does not mandate a 406MHz ELT, but it does mandate a device approved under TSO C91a (for new installations on US-registered aircraft) or any of the versions of TSO C126.
 
Almost as funny as an American who remains unaware of FARs, despite the best efforts of others to lead him into the light... ;)

Excellent... need neighbors to our north to help straighten out American politics as well.

And that isn't even funny. :mad:
 
Mark,

Some ELTs use Duracell D cells. That would seem to contradict your conclusion.

Rich

The designer and Manufacturer of that ELT specifically specified Duracell D sized batteries (with expiration date) so using them as replacements (actually when delivered, the new the ELT's came without any batteries) met the TSO.

91.207 Emergency locator transmitters.

(a) Except as provided in paragraphs (e) and (f) of this section, no person may operate a U.S.-registered civil airplane unless -

(1) There is attached to the airplane an approved automatic type emergency locator transmitter that is in operable condition for the following operations, except that after June 21, 1995, an emergency locator transmitter that meets the requirements of TSO-C91 may not be used for new installations:

91.207 also dictates what inspections and record keeping of those inspections is required for all U.S. civil aircraft.
 
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Oh No - Not BIEBER!!!! :)

Just a brief note... The D-cell powered ELTs are strictly 121.5MHz units certified under TSO C91 or C91a, not the 406MHz units certified under TSO C126 and its later variants.

Thanks, Scott for citing chapter and verse. There are exceptions to the "no TSO required" generality for Experimental aircraft, and ELT's are definitely one of them. Non-TSO'd ELTs simply don't meet the requirements of the FAR as quoted by Scott. Using non-approved batteries invalidates the TSO, therefore an ELT with unapproved batteries installed is in violation of the FARs. This same story goes for 121.5MHz units as well as 406MHz units - we can only install batteries approved by the ELT manufacturer.

Coming back to the OP's point, yes, the approved batteries are expensive, but they do last for 5 years or more, so the average annual cost isn't terribly much more than the battery packs we are accustomed to buying for our older 121.5MHz ELTs. The exceptions as pointed out previously are the D-cell-powered units, cuz there ain't gonna be a cheaper ELT battery than good ole' copper tops!
 
OK, you're all busting my chops over the ELT battery thing. The full text of the FAR is:

91.207 Emergency locator transmitters.
(a) Except as provided in paragraphs (e) and (f) of this section, no person may operate a U.S. registered civil airplane unless?

(1) There is attached to the airplane an approved automatic type emergency locator transmitter that is in operable condition for the following operations, except that after June 21, 1995, an emergency locator transmitter that meets the requirements of TSO-C91 may not be used for new installations:

(i) Those operations governed by the supplemental air carrier and commercial operator rules of parts 121 and 125;

(ii) Charter flights governed by the domestic and flag air carrier rules of part 121 of this chapter; and

(iii) Operations governed by part 135 of this chapter; or

(2) For operations other than those specified in paragraph (a)(1) of this section, there must be attached to the airplane an approved personal type or an approved automatic type emergency locator transmitter that is in operable condition, except that after June 21, 1995, an emergency locator transmitter that meets the requirements of TSO-C91 may not be used for new installations.

(b) Each emergency locator transmitter required by paragraph (a) of this section must be attached to the airplane in such a manner that the probability of damage to the transmitter in the event of crash impact is minimized. Fixed and deployable automatic type transmitters must be attached to the airplane as far aft as practicable.

(c) Batteries used in the emergency locator transmitters required by paragraphs (a) and (b) of this section must be replaced (or recharged, if the batteries are rechargeable)?

(1) When the transmitter has been in use for more than 1 cumulative hour; or

(2) When 50 percent of their useful life (or, for rechargeable batteries, 50 percent of their useful life of charge) has expired, as established by the transmitter manufacturer under its approval. The new expiration date for replacing (or recharging) the battery must be legibly marked on the outside of the transmitter and entered in the aircraft maintenance record. Paragraph (c)(2) of this section does not apply to batteries (such as water-activated batteries) that are essentially unaffected during probable storage intervals.

(d) Each emergency locator transmitter required by paragraph (a) of this section must be inspected within 12 calendar months after the last inspection for?

(1) Proper installation;

(2) Battery corrosion;

(3) Operation of the controls and crash sensor; and

(4) The presence of a sufficient signal radiated from its antenna.

(e) Notwithstanding paragraph (a) of this section, a person may?

(1) Ferry a newly acquired airplane from the place where possession of it was taken to a place where the emergency locator transmitter is to be installed; and

(2) Ferry an airplane with an inoperative emergency locator transmitter from a place where repairs or replacements cannot be made to a place where they can be made.

No person other than required crewmembers may be carried aboard an airplane being ferried under paragraph (e) of this section.

(f) Paragraph (a) of this section does not apply to?

(1) Before January 1, 2004, turbojet-powered aircraft;

(2) Aircraft while engaged in scheduled flights by scheduled air carriers;

(3) Aircraft while engaged in training operations conducted entirely within a 50-nautical mile radius of the airport from which such local flight operations began;

(4) Aircraft while engaged in flight operations incident to design and testing;

(5) New aircraft while engaged in flight operations incident to their manufacture, preparation, and delivery;

(6) Aircraft while engaged in flight operations incident to the aerial application of chemicals and other substances for agricultural purposes;

(7) Aircraft certificated by the Administrator for research and development purposes;

(8) Aircraft while used for showing compliance with regulations, crew training, exhibition, air racing, or market surveys;

(9) Aircraft equipped to carry not more than one person.

(10) An aircraft during any period for which the transmitter has been temporarily removed for inspection, repair, modification, or replacement, subject to the following:

(i) No person may operate the aircraft unless the aircraft records contain an entry which includes the date of initial removal, the make, model, serial number, and reason for removing the transmitter, and a placard located in view of the pilot to show ?ELT not installed.?

(ii) No person may operate the aircraft more than 90 days after the ELT is initially removed from the aircraft; and

(11) On and after January 1, 2004, aircraft with a maximum payload capacity of more than 18,000 pounds when used in air transportation.

[Docket No. 18334, 54 FR 34304, Aug. 18, 1989; as amended by Amdt. 91?242, 59 FR 32057, June 21, 1994; Amdt. 91?242, 59 FR 34578, July 6, 1994; Amdt. 91?265, 65 FR 81318, Dec. 22, 2000]


Now it is interesting that the FAR says it must be "operable", not airworthy or TSO'd. The actual TSo for ELTs would seem to indicate the battery must meet the manufacturer's spec as demonstrated for TSO compliance. If I found a cheaper battery that matched the spec I would use it and would argue the TSO is met. if not it would still be "operable" even if not in compliance with the TSO.

In the nuke world I come from we used to do operability analysis all the time when something wasn't quite right. If we could show the design basis was met it was operable.

RELAX, CANUCKS --- I wouldn't inflict Bieber on my worst enemy, but we're keeping Celine!😁
 
. . .Now it is interesting that the FAR says it must be "operable", not airworthy or TSO'd. The actual TSo for ELTs would seem to indicate the battery must meet the manufacturer's spec as demonstrated for TSO compliance. If I found a cheaper battery that matched the spec I would use it and would argue the TSO is met. if not it would still be "operable" even if not in compliance with the TSO.

In the nuke world I come from we used to do operability analysis all the time when something wasn't quite right. If we could show the design basis was met it was operable.
A man after my own heart!

I find it interesting that we pilots love to deride the FAA for all manner of things, including the rules they bring forth. Then in the very next breathe chastise a fellow pilot for 'violating' those very rules.

It is my fervent belief that, no matter how well intentioned the original purpose for the FAA TSO concept, the truth driving TSO's is based more on profit rather than safety in today's overly regulated world! TSO's have done more to create government sanctioned monopolies than they have moved the industry toward safety.

My unsolicited .02 on the topic. . . but now that I hit the submit reply button I keep thinking maybe I should learn to keep my unsolicited opinions to myself. Oh well, guess I 'done gone and done it' anyway! Y'all Live Longer and Prosper!
 
small minded experts

Even in the "best" forums... and this one is superb, EXPERTS wait in the wings to voice our transgressions publicly. It seems like odd psychology, but is pervasive. VAF is no exception, just less frequent. I once took a tour of a major ELT manufacturing plant. The pallets of Duracell D cells waiting to be spot welded were taking a whole corner of the plant. The general manager indicated he made way more money on batteries than the actual transmitters.
The rub, in the DIY world now, is the software that keeps track of battery usage. Those technically minded members here would welcome feedback on how the "rebuild" task goes for those that try it. Just be aware that someone is lurking to out there to "violate" you on the forum.
 
Chris - I would advise you do some research on this topic. The ONLY battery which can be used as a replacement battery in your ELT is the battery manufactured and supplied by the ELT manufacturer. The battery makes up part of the TSO certification. Even though you are in an Experimental aircraft, you MUST use a TSO'd ELT. There is no room for interpretation on this point. Use something other than the manufacturer-approved battery in your 406MHz ELT and you do not have a TSO'd ELT, therefore you are in contravention of the FARs. Very simple, very clear-cut, and not open to interpretation, as has been discussed here at length previously.

Again, to put a fine point on it. NO HOMEBUILT BATTERY PACKS for 406MHz ELTs. Period.

My aircraft, engine, prop, and ELT are all experimental...Non-TSO (I install it as far back as I see fit). It would help if you identify which "FAR" you are referring too? I live in the USA, not Canada.

This is simply a battery replacement, in which the MFG has "glued" the batteries into a separate battery case.

The batteries should be here late this week. I'll let you know if I have any problems with the timer, but looking at it, it will more then likely reset after the battery is disconnected.
 
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Dave,

I see by your profile you are a lawyer. Remember, the nature of your profession is that half of you are wrong at any given time!😜

Rich (AKA Wannabbe war criminal)😁
 
Chris,
It's not a timer and it won't reset with a new battery. They use a 1Kb serial EEPROM (Google 93C46) , it needs to be reprogrammed. It will continue to work with a new battery...until you reach your 120th, 30 second tic and flag the expired battery fault code.
 
Mike,

If I read your post correctly the ELT would work for an hour and then generate a battery fault code. What is the significance of that fault code? Does it cause the ELT to stop transmitting? Does it cause the signal to be ignored by the SARSAT? If the ELT continues to transmit a valid signal with the fault code then why is it an issue?

Rich
 
Chris,
It's not a timer and it won't reset with a new battery. They use a 1Kb serial EEPROM (Google 93C46) , it needs to be reprogrammed. It will continue to work with a new battery...until you reach your 120th, 30 second tic and flag the expired battery fault code.

https://www.pjrc.com/tech/8051/serial-eeprom.html

As long as I don't set off the general purpose flag, its good as new. And if I go pass 120 seconds, the only down side is a "general purpose flag" is set"? I'll let you know when I get the batteries. I might even set off the ELT with the existing batteries, before installing the new batteries, as a test.

This could be a problem for future sales, as other competitors will make lithium battery replacement less costly to the experimental market, and include a reset feature, to increase market share.;)
 
This truly is a circular discussion. The FAR quoted earlier contains ONE CRITICAL WORD that folks are overlooking. That word is "approved".

The focus currently is on the unit being in operable condition. Sure, replacing the batteries with a home-brew battery pack may result in an ELT that's operable. But it will not result in an ELT that is "approved".

"Approval" is based on compliance with the applicable TSO. Install a battery pack which is not listed in the installation/operation/maintenance manual and you no longer have an ELT which meets the TSO. It really is simple. Home-brew battery pack = unapproved device = unapproved ELT = contravention of the FARs.
 
Mark,

We aren't talking about "home brew" batteries. We are talking about cheaper batteries from an alternate supplier that meet form, fit and function. Same geometry, same amp-hour rating and same chemistry, just not provided through the ELT manufacturer.

It's interesting that the pulse counter described in one of the posts would give a fault code in a valid actuation after 120 pulses even if it was new out of the box from the manufacturer with their battery. Would that make the ELT inoperable after it was broadcasting for one hour?


Rich
 
moot points

Rich, exactly... At that point, the software considers the battery capcity to transmit for a time period by design is compromised.
Remember, all of this is designed to give us confidence in a product designed to save our lives. There is no perfect solution. Many accidents report lack of triggering with a simple G switch.
The 406 technology is leaps and bounds ahead of 121.5
It is digital and transmits in bursts with location data in most units. A long time of transmitting is not really as critical as it was when homing on a 100mw signal was required. None of the units will stop transmitting with a low battery fault code, so much of this is a moot point. It simply tracks back to the question: Do we install these to meet a regulation, or to save our souls? For those looking to replace a battery in an economical fashion and have some assistance in finding a downed RV, the original posters actions will be just fine.
The regulation lawyers here and others will paste FAR's until the ink runs dry.
As I have noted in other posts, I have never seen the FAA show up at pilot funerals.
 
Would that make the ELT inoperable after it was broadcasting for one hour?

Yes as far as being legal to fly with.
It is one of the requirements stipulated in the FAR that was referenced earlier in this thread.
The count that the battery keeps is for compliance with that FAR requirement of battery replacement if the ELT has been activated and transmitted for a cumulative time of 1 hr or more (regardless of the reason for the activation).
 
Can someone say how this fault code is displayed? I'm not familiar with the Artex 406 having a monitor for displaying status.
 
Can someone say how this fault code is displayed? I'm not familiar with the Artex 406 having a monitor for displaying status.

The owner's manual for this ELT produced by ARTEX is the best place to see this info. In it you'll discover the fault codes are annunciated by an LED on the remote control panel as well as via an audio buzzer.
 
Scott, 2(c) of the FAR refers to battery usage, not a counter. If you know the replacement battery is equivalent to the original manufacturer's then the counter seems irrelevant.

I really don't understand the position that only a battery with the OEM logo on it is acceptable. Remember that ROTAX 912 UL and ROTAX 912 ULS engines roll off the same factory line. The only difference is the paper trail. If you buy a battery that meets the OEM spec there should be no hesitation in using it. It can be a significant cost savings for the same performance.
 
We keep coming back to the same point in this discussion. The FARs require a TSO'd ELT. While we might be able to source the individual lithium D-cells used to fabricate the battery pack, the only replacement part certified under the TSO approval is the battery pack in its entirety, not the individual cells.

The Artex ME406 Description, Operation, Installation and Maintenance Manual states the following:
SUBTASK 25-62-30-990-001
A. Purpose
1) This illustrated parts list (IPL) illustrates and lists the spare parts, with attaching hardware, applicable to
the ME406 Series ELT.
2) Parts and components not listed herein, are not field replaceable and ELT repairs requiring parts outside
the scope of this manual must be accomplished by the manufacturer.

The parts list then lists the following part as being the approved replacement part:
452-6499 . ME406 Lithium Battery Pack

Note this is the battery PACK, not the individual D-cells. Note the text above also indicates "parts and components not listed herein are not field replaceable".

The bottom line remains the same... Replacing the individual D-cells is specifically and clearly an activity which will invalidate the TSO approval of the ELT. In simple terms, as stated before. Homebrew battery replacement = unapproved part = invalidation of TSO = contravention of the FARs.

I'm just like the next guy - I like to save a few bucks where I can. Having already purchased a replacement ME406 battery pack I can certainly sympathize with the OP - it's an expensive part, but a necessary part required to maintain the airworthiness of the ELT. Please think twice before willfully and knowingly installing unapproved parts in your airplane.
 
You originally asked the following question....
Would that make the ELT inoperable after it was broadcasting for one hour?

I answered that question by writing

Yes as far as being legal to fly with.
It is one of the requirements stipulated in the FAR that was referenced earlier in this thread.
The count that the battery keeps is for compliance with that FAR requirement of battery replacement if the ELT has been activated and transmitted for a cumulative time of 1 hr or more (regardless of the reason for the activation).

The reason is that FAR 91.207 also says....

(c) Batteries used in the emergency locator transmitters required by paragraphs (a) and (b) of this section must be replaced (or recharged, if the batteries are rechargeable)--
(1) When the transmitter has been in use for more than 1 cumulative hour; or
(2) When 50 percent of their useful life (or, for rechargeable batteries, 50 percent of their useful life of charge) has expired, as established by the transmitter manufacturer under its approval.


Because of this part of 91.205, the newest TSO requirements for ELT's require them to monitor battery usage and report when the usage limit has been exceeded.


Scott, 2(c) of the FAR refers to battery usage, not a counter. If you know the replacement battery is equivalent to the original manufacturer's then the counter seems irrelevant.

I really don't understand the position that only a battery with the OEM logo on it is acceptable. Remember that ROTAX 912 UL and ROTAX 912 ULS engines roll off the same factory line. The only difference is the paper trail. If you buy a battery that meets the OEM spec there should be no hesitation in using it. It can be a significant cost savings for the same performance.

This has nothing to do with that original question so I am not sure why you quoted me in your post........

You can interpret all of this how ever you want and do what ever you want. In the end, your debating is pointless because the only interpretation that matters is the FAA's. Just because you don't think it makes sense doesn't change the meaning.

- Blunt and to the point alert -

I am always amaze that the people that complain the most about all of the rules we have, usually seem to be the same people that are always looking to push the to fringe edge limit of following those rules.

If you haven't figured it out yet.... that is predominately what keeps the FAA issuing more rules......
 
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Rules are someone's opinion

Scott
This seems to be a two way street to me.
I think that some rules need a second look, this is 2017.
Like the third class medical.

Rules are someone's opinion, Just ask a room full of Republicans and Democrats.

I am glad that we are not all sheep.
My View.

Joe Dallas
 
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Scott
This seems to be a two way street to me.
I think that some rules need a second look, this is 2017.
Like the third class medical.

Rules are someone's opinion, Just ask a room full of Republicans and Democrats.

I am glad that we are not all sheep.
My View.

Joe Dallas

I don't disagree with you, but I can't think of a single rule related to aviation certifications or operating requirements that was ever changed because a bunch of the pilot community was complaining about it and failing to comply.......

What we do have good historical evidence of is that non compliance will just result in more rules that we don't like.
 
Carl and Scott,

Your comments are a bit harsh. I am only stating my interpretation of the trquirements as you are. Statements regarding those who offer the opinion are neither persuasive nor well received.

Rich
 
This morning I submitted the following question by email on the FAA website.

I have an ELSA aircraft. Does the ELT in an experimental aircraft have to be TSO'd? If the unit is TSO'd and requires a new battery can an equivalent commercial grade battery from a source other than the original ELT manufacturer be used and still meet the "operable" requirement of FAR 91.207(a)(1)?

Thank you
Richard Schaller

Let's see what they say.
 
The Recommends.....

With great trepidation, I will submit my own experiences on this issue.

During a recent IA renewal course, the FSDO presented an informative briefing on A&P / IAs working on EAB aircraft. Please note, that none of the following are FAA regulations, just their "recommendations";

1. The FAA recommends the use of materials of established quality, such as those produced under a TSO, Mil-Spec, SAE or AN standard.
Note - There is no regulation that prevents the use of hardware store materials on an EAB aircraft. Because the specific strength and durability of these parts is unknown, the use of these parts is not recommended by the FAA, even thought there is no specific regulation prohibiting their use.

2. A&P I/As who maintain EAB aircraft are still expected to use materials, techniques and practices that are acceptable to the Administrator.

As an A&P IA who built an RV and does Condition Inspections on EAB aircraft, I asked the Inspector about the consequences of using Home Depot parts and hardware on EAB aircraft. The Inspector told me that the FAA can only recommend using parts of "known quality" on EAB aircraft, but there is specific regulation prohibiting the use of any parts from unknown sources. With that being made very clear, he did say that if an EAB aircraft that I had signed off as "in a Condition For Safe Operation" was in an accident and it was determined that I had used a part that was determined to be "Not recommended for aircraft use" and was found to be contributing to the accident, the FAA would likely find me (not the aircraft) negligent under Part 43 and 65.

Having been through a few accident investigations, the FAA and NTSB are usually friendly and easy to work with. Its the insurance company and lawyers who might look to find you negligent for not following "FAA recommendations".

The only recommendation is that if you use parts on your EAB aircraft of unknown quality and durability, have your explanation ready for how you determined that part was "safe for operation" on that EAB aircraft and how your knowledge of it stands against that FAA's recommendation.

I am not sure how the FAA views EAB aircraft Repairmen's "performance rules" as they relate to determining "safe for operation" type questions, but the FSDO inspector was clear that A&Ps would be held to higher standard in their judgment.

Most of this drawn from AC 20-27G and Parts 43 and 65.

Looks like the bottom line is this: You can do what you want on an EAB aircraft, but be prepared to live (or die) with your decisions.

In the case of a 406 MHz ELT, that is a piece of potentially life saving equipment...one might want to use their best judgment on replacing the batteries and testing / registering it.
 
As much as I hate to sound contrarian, there are a few exceptions to this "you can do as you like" approach to Experimental aircraft.

As discussed previously in this thread, for almost all aspects of these aircraft there is no need to comply with TSO's, manufacturer's AD's etc. Emergency Locator Transmitters are a very, very clear exception.

TSO compliance is mandatory for ELT's.

Please re-read the posts above in which the applicable FAR is quoted, and which highlights the requirement to use an approved device. The only approved devices are those meeting TSO C91, C91a and C126 and its variants. There's no room for interpretation here.

During your IA renewal course, had you asked the question specifically about ELT's, you would have (or should have) received very specific guidance as ELT's are one of the very few pieces of equipment where TSO compliance is mandatory in EAB aircraft.

EDIT: for clarity's sake, it should be noted that ELT's meeting TSO C91 (note lack of "a" suffix) are specifically NOT approved for new installations in US-registered aircraft. An ELT complying with TSO C91a is the minimum required for a new installation. ELTs complying with TSO C126 (covering 406MHz units) are also considered approved equipment for new installations as well as retrofit installations. Note that a "new" installation doesn't mean a new airplane, but rather a new installation. If you have, for instance, an old Narco 10 ELT meeting TSO C91 installed in your airplane and you wish to replace it, you cannot replace it with another brand of C91 ELT - at a minimum, an ELT meeting TSO C91a is required. If your aircraft already has that Narco 10 installed and it dies, you can replace it with another Narco 10 unit.
 
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. . .Looks like the bottom line is this: You can do what you want on an EAB aircraft, but be prepared to live (or die) with your decisions.

In the case of a 406 MHz ELT, that is a piece of potentially life saving equipment...one might want to use their best judgment on replacing the batteries and testing / registering it.
No dispute on the logic but that logic would hold true for everything one does or provides in the aircraft. So:
You can do what you want on an EAB aircraft, but be prepared to live (or die) with your decisions.
would hold true for the clothes you wear while flying; the survival equipment you choose to place in your baggage compartment; the type of firewall insulation you choose to install (or not install); the amount of fuel in your tanks you choose to take off with; the type of fuel you use, or where you get that fuel; the weight limit you set for your plane; the type of navigation equipment you install; the installation of dash padding installed; type of seat belts used; and on, and on, and on, and on. . .

This statement does indeed hold true for EVERYTHING chosen for our experimental aircraft. Why would the battery purchase/installation for an ELT be any different than the decision made for any of these other ad infinitem things? What part of any FAA regulation concerning abiding by a TSO would ever circumvent, add to, or expound upon this undeniable truth?

If one were to contemplate the issue of a TSO'd battery 'pack' for an ELT, the reality is this: that system is designed to help discovery/recovery in the case of a downed aircraft. When one argues whether it violates the AIRWORTHINESS of the aircraft I can only ask: "Really?"

That word can only be discussed in this context in terms of whether the TSO, the aircraft, the ELT, the Battery Pack for the ELT meets the government regulations such that the said government would allow the aircraft to perform its designed purpose in its airspace. That word does NOT hold truth in the context of the true meaning of the word when thinking in terms of the capability of the aircraft to sustain successful flight. What part does that battery pack serve to keep that aircraft flying? Or breaking? Or falling out of the sky? Or providing for any other aspect of allowing that aircraft to perform its designed function of flight? To argue the legalities of AIRWORTHINESS in this debate's context is solely limited to whether one should abide by rules and regulations set forth. I do not believe it bears well in context of a discussion about the safety of flight, which is what I think about when contemplating the meaning of the word AIRWORTHINESS.

Live Long and Prosper!
 
If one were to contemplate the issue of a TSO'd battery 'pack' for an ELT, the reality is this: that system is designed to help discovery/recovery in the case of a downed aircraft. When one argues whether it violates the AIRWORTHINESS of the aircraft I can only ask: "Really?"

Yes.

And in the event that an ELT should be required, and it has a non-approved battery pack, and it still functions as intended - neither the rescuers nor the rescued are going to give a flying flip whether or not the battery was approved. The fact that it worked (or not) is all that matters.
 
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