Looking for a Battery Capacity Tester

[A64Pilot]

On 9/19/2021 at 9:49 PM, PT20J said:

Well, I respectfully disagree with @N201MKTurbo and @A64Pilot. 

First of all, the certification basis for Mooneys is, per the TCDS, CAR 3, so Part 23 requirements are irrelevant.

Second, it is established FAA policy that for light, non-turbine aircraft operated under part 91, TBO, Service Bulletins, and Aircraft Maintenance Manual inspection/overhaul/replacement intervals, and ICAs are not required EXCEPT when specifically included in a LIMITATIONS section (which is rare).  What is required is described in FARs 91 snd 43.

So, for a Mooney operated under Part 91, you are not required to replace the landing gear actuator no back spring at 1000 hours even though the Mooney Service and Maintenance Manual says to do so. Similarly, you do not need to perform a capacity check although the battery manufacturer’s ICA says to do so.

Here is Mike Bush’s explanation.  https://www.aopa.org/news-and-media/all-news/2019/september/pilot/savvy-maintenance-safety-continuum

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You know I said that FAR 23 would only apply to FAR 23 aircraft, which we aren’t.

I suspect the requirement for a yearly cap check is in the ICA of each battery. My take and the take of the PMI’s that I’ve had is that ICA’s are mandatory, A whole lot of Aircraft Maintenance is actually up to opinion, just better be able to defend your opinion when things go bad, Look at Mike’s article you linked to, is he saying it’s a fact, or his opinion?

Life limited parts, even if the life limits not established by AD are also mandatory, wing spar life limit of a CAR 3 Certified S2R-T34 is 29,000 hours, that a limit, exceed that life limit and the aircraft is no longer airworthy. 

TBO’s are not life limits.

Life limited parts will be found I believe in the Airworthiness section of the aircraft Maintenance Manual.

Edited September 22, 2021 by A64Pilot

[PT20J]

1 hour ago, A64Pilot said:

You know I said that FAR 23 would only apply to FAR 23 aircraft, which we aren’t.

I suspect the requirement for a yearly cap check is in the ICA of each battery. My take and the take of the PMI’s that I’ve had is that ICA’s are mandatory, A whole lot of Aircraft Maintenance is actually up to opinion, just better be able to defend your opinion when things go bad, Look at Mike’s article you linked to, is he saying it’s a fact, or his opinion?

Life limited parts, even if the life limits not established by AD are also mandatory, wing spar life limit of a CAR 3 Certified S2R-T34 is 29,000 hours, that a limit, exceed that life limit and the aircraft is no longer airworthy. 

TBO’s are not life limits.

Life limited parts will be found I believe in the Airworthiness section of the aircraft Maintenance Manual.

It is not Mike's opinion -- it is FAA interpretation of the regulations.

14 CFR Part 91.403(c) clearly states that only "mandatory replacement times, inspection intervals and related procedures" listed in the Airworthiness Limitations section of a maintenance manual or ICA must be complied with.

Here is an FAA legal interpretation where FAA counsel was asked if ICAs were mandatory under part 135. In answering the question, the FAA lawyer pointed out in the second paragraph that (except for the airworthiness limitations section) ICA compliance was not required for non-air carrier general aviation aircraft.

Schultz-Seaport_2009_Legal_Interpretation.pdf

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[A64Pilot]

11 hours ago, PT20J said:

It is not Mike's opinion -- it is FAA interpretation of the regulations.

14 CFR Part 91.403(c) clearly states that only "mandatory replacement times, inspection intervals and related procedures" listed in the Airworthiness Limitations section of a maintenance manual or ICA must be complied with.

Here is an FAA legal interpretation where FAA counsel was asked if ICAs were mandatory under part 135. In answering the question, the FAA lawyer pointed out in the second paragraph that (except for the airworthiness limitations section) ICA compliance was not required for non-air carrier general aviation aircraft.

Schultz-Seaport_2009_Legal_Interpretation.pdf 1.08 MB · 1 download

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I used to run into similar problems with the FAA MIDO, the first part you quoted was the LAW, the CFR part, the second isn’t, it’s an interpretation.

The FAA will waffle back and forth on that issue, you can quote an AC for example to them showing you complied with an AC that was written to clarify the FAR as many AC’s are and they won’t accept it, then on the next issue you follow the FAR to the letter, and they make you comply with an AC. So you argue they they can’t do that as an AC is not regulatory. only an FAR is.

And you’ll be right, but you probably won’t win. Argue with them and you’ll lose your DER, not for arguing, but they will get tired of you and eventually they will get rid of you. Substitute DER for IA or A&P etc.

I’ll concede that almost certainly your correct, that you can get away without complying with ICA’s, but unless they are exceedingly egregious I maintain that it’s best to follow them, they are in fact written to ensure that an item remains airworthy, battery for instance, if you fly IFR it’s in your best instance to ensure that if you lose the charging system that the battery can continue to operate instruments, Comm and Nav systems until you can get down. It makes one wonder how many spatial disorientation crashes may have been the result of a battery quitting.

How long will the battery last? Not too hard to calculate, divide amp draw by number of amp hours the testing determined for the battery to have. Amp draw isn’t too hard to determine, with the engine off, turn everything on and see how many amps the amp meter is indicating, that will be close.

In short the FAA FAR’s, policy letters. Orders AC’s etc are all shot full of errors, it’s almost comical.

‘The TCDS is and has always been considered the bible for aircraft conformity, yet read this order and see just how screwed up the FA admits TCDS’s are

https://www.faa.gov/documentLibrary/media/Order/FAA_Order_8110.121.pdf

In short as a maintainer you really do have to and are actually required to exercise your best judgement and decide what is the best course of action to follow, usually that’s the most conservative and which materially increases safety. You may can get away with not changing no back clutch springs and cap checking batteries, but is that really the right thing to do?

Then finally as many find out the insurence industry runs aviation as much as the FAA, how will your insurence company react when they find out that the gear up landing was caused by a overdue for replacement no back clutch spring? I honestly don’t know as I’ve not had that conversation, but suspect it may not go well. 

Finally as shown with the TCDS link, you’ll often run into FAA regs that are simply incorrect, that’s what the PMI is for, if you have a good one they will help.

 

On edit, maybe a better example is an SB, do you follow Lycoming’s “Mandatory” SB on parts replacement when you do a prop strike inspection? Or do you say I’m not going to do it because they can’t make me, part 91 SB’s aren’t required? https://www.lycoming.com/sites/default/files/Mandatory Parts Replacement at Overhaul and During Repair or Maintenance.pdf

In my opinion in this instance your foolish not to comply with it as it will most likely breathe years and hundreds of hours into an engine, and the cost when compared to the benefits is minimal, however I readily concede that is not always the case for all SB’s, and that’s when a maintainer should exercise his or her best judgement to guide the owner, using some common sense, for instance if the hoses are six months old, don’t replace them, but if over five years do so.

The cost to cap check a battery is minimal, but the cost not to isn’t.

Edited September 22, 2021 by A64Pilot

[PT20J]

30 minutes ago, mike261 said:

so...

I haven't researched the above regs, or done a deep dive, but being in the electrical trade, I have done many UPS battery tests, some with electric heaters, but more with actual equipment loads...shut of the main and start the stop watch. this maybe an over simplification, but why not just simulate it on the ground with the actual equipment? turn on the battery, shed the loads with breakers and start the stopwatch?

 

Mike

Mike,

No reason you cannot do that, and I think it is a worthwhile test because what you really want to know is how long the battery will keep the instruments alive if the charging system fails. 

However, as @DonMuncy pointed out above, the manufacturer’s capacity test   described in the ICA is performed at a constant discharge current, not a constant load. So, if you are an air carrier, you have to follow the procedure in the ICA. For general aviation, you can do whatever test gives you comfort that the battery has adequate capacity for your purposes. 

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