Newbie battery question

Brian A Johns

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I just bought a PA28-180 Cherokee and think I need a new battery. The current batt barely turns over the motor. As best I can tell it was installed in August 2006 and is a Gil G-35. That's over 11 years on the battery so I can believe it's time. After reading some it would appear replacing with a concorde RG-35A or RG-35AXC are highly preferred by this crowd and others. So, my questions are below. Go easy, new pilot, new aircraft owner so these may be obvious but I can't figure it out.

1) I seem to be reading this is legal for me as a pilot and owner to do to my own plane. Correct?

2) If I replace with the Gil with a Concorde AGM battery, do I need an STC or anything other than a log book entry. It seems that is all I need but was reading some of the concorde literature and an FAA AC 23-27 for vintage aircraft parts replacement and it says I can replace any group 35 batt with any other as long as they are within 1 lb of each other. These are NOT. 27 lbs for Gil, 29.5 for the RG-35A and 32lbs for the RG-35AXC.

3) I don't know if I need an STC or I am reading FAA/PMA wording and am confused about all of this. Any advice appreciated.

4) Do I need my W/B reworked if I do this?

Maybe I am overthinking this but its just a lb or two and a battery swap. Should take 10 minutes but I keep thinking about things that might not be legal about this.

Thanks in advance for any advice or experience.
 
Check out this archived post. I replaced the battery in my 172L and it was very simple process. Replaced a Concord with a Gill. It made a huge difference cranking in this very cold weather. The biggest problem is replacing the battery cover pins.

https://www.pilotsofamerica.com/com...ng-aircraft-battery-as-a-private-pilot.57336/

also:

10FAR Part 43 contains the information of what you can and cannot do to an aircraft and what requirements you must have.

If you are a certificated Private Pilot (as in not a sport pilot), there are quite a few things you can do to an aircraft you own, that is not used for commerci
al purposes
. Like:
  • Replacing and servicing batteries
 
1) I seem to be reading this is legal for me as a pilot and owner to do to my own plane. Correct?

2) If I replace with the Gil with a Concorde AGM battery, do I need an STC or anything other than a log book entry. It seems that is all I need but was reading some of the concorde literature and an FAA AC 23-27 for vintage aircraft parts replacement and it says I can replace any group 35 batt with any other as long as they are within 1 lb of each other. These are NOT. 27 lbs for Gil, 29.5 for the RG-35A and 32lbs for the RG-35AXC.

3) I don't know if I need an STC or I am reading FAA/PMA wording and am confused about all of this. Any advice appreciated.

4) Do I need my W/B reworked if I do this?
1) Yes under Part 43 Append A (24)

2) Logbook entry only. The reason AC 23-27 references the "within 1lb" limitation is because the FAA acceptable negligible weight change for aircraft up to 5000lbs empty weight is 1lb and 2lbs for aircraft 5000lbs to 50,000lbs.

3) If Concorde part number is a PMA replacement for the original battery P/N then no on STC. AC 23-27 also gives you similar flexibility.

4) Technically, any weight change over the 1lb limit requires the aircraft empty weight to be revised by a mechanic due to the empty weight and CG record are an original certification requirement and only a mechanic can it sign off. Instead of using the published weights, physically weigh each battery prior to install and compare weights. Be sure the Gil is fully serviced water-wise. The weight difference may be closer than the published numbers. Also, ensure your aircraft equipment list is updated.
 
4) Technically, any weight change over the 1lb limit requires the aircraft empty weight to be revised by a mechanic due to the empty weight and CG record are an original certification requirement and only a mechanic can it sign off.

Show me that in a FAR rule.
 
Show me that in a FAR rule.

The empty weight and balance record is part of the type certificate (Part 21/23) and a certification requirement for issuance of an Airworthiness Certificate (8130.2J). The record is part of the aircraft. It requires an alteration/repair (over 1lb) to change those records (8083-1B). So, who can perform that alteration/repair to a Type Certificated aircraft?
 
Gil now offers AGM batteries like Concorde. Their earlier sealed batteries were supposedly awful, but I think the latest generation are comparable to Concorde. Depending on when the stuff you read was posted, it may be referring to older products?

I think if you need an STC, Concord will provide it. http://www.concordebattery.com/faa3.php?id=2431
 
Concorde provides the STC and ICA. If weight and balance has to be altered a mechanic has to be involved at some level. If you go with the AXC then a new weight and balance will be needed.
 
Hi Brian, that is a record time (11 years) for a Gill. I bet it was changed half way between ie at 5 years. That is more typical for wet cell batteries.
Minor point. Just wanted to welcome you.
 
Hi Brian, that is a record time (11 years) for a Gill. I bet it was changed half way between ie at 5 years. That is more typical for wet cell batteries.
Minor point. Just wanted to welcome you.

Thanks! I suspect you may well be right but I cannot seem to find the entry anywhere and I have complete records. Like you say, even half way it's probably time. Barely spins it over. Maybe some other issue but I suspect the battery. Even had it just 'click' once and not engage the bendix. I will pull it out here tomorrow and see if the battery says anything on it as well.
 
Concorde provides the STC and ICA. If weight and balance has to be altered a mechanic has to be involved at some level. If you go with the AXC then a new weight and balance will be needed.


Thank you. Sorry for my ignorance but what is an 'ICA'? I have all the info I need from the original equipment list that shows the Gil weight and ARM so re-doing the W&B should be trivial. I understand the mechanic needs to formalize that but it shouldn't be a big deal I wouldn't think since I can generate the actual numbers right now.
 
ICA is the instructions for continuing airworthiness. Tells you what to do to it on a regular basis to keep it legal.
 
@Brian A Johns, I had a recent "pilot deviation" which resulted in our aircraft logs being reviewed. The A&P ASI was pretty cool about things and caught one flub on our part. We had replaced a old headlight with a Prometheus LED head light. When online I thought I found the STC so I referred to the STC in the entry...No-No!...I believe that requires a 337 via IA?? But the ASI said he was positive there was a PMA for these LED lights and said to replace the entry with a reference to the PMA number instead. So that was easy.

Since I am student pilot I had been reading 14 CFR rather recently, I recalled reading that only a Private, Commerical or ATP can return the aircraft to service so my wife signed it off with her commercial. And you also need to use specific wording in the log entry regarding return to service.

Sounds like the tricky part is W&B. Wouldn't it be best to at least describe the weight being removed, weight be installed and net difference in the log entry. According to the ASI, he said do whatever you can to make it as clear as possible what was changed so that any dive into the logs is as easy for everyone as possible. If you are lucky the W&B might be under 1lB. Maybe during your next annual you can mention it was changed and have them rework W&B then?

Oh yeah, our old Gil battery was cranking pretty bad at the end of the summer. During the annual the mechanic looked and said the battery tender connection at the terminal caused it to corrode, he cleaned it off and it was like new. Probably due to dissimilar metals?
 
Not all STCs require a Form 337. All depends if it is a major alteration vs a minor alteration.
Thank you for clarifying! What made me think it was all STC's was that we had installed Rosen Visors and IIRC, the A&P had to do the 337 for those??? Maybe I am remembering that wrong. But they were so simple to install. We had made our own log entry but it was like he made it right :)
 
What made me think it was all STC's was that we had installed Rosen Visors and IIRC, the A&P had to do the 337 for those???

I always defer to the person signing the work as to what paperwork they require.

But for future reference, a STC and a Form 337 are separate document tracks and used for different purposes. A STC is one of several design/production approval methods used by a manufacturer to approve parts/alterations for use on TC’d aircraft.

The STC doesn’t indicate the complexity of the part (as your Rosens) but simply the FAA approval of that item. In some cases, a part mfg’r will use the STC process over a PMA process if they have an item that can be used on various aircraft models vs a single model, like a fabric covering system.

This type of STC allows the mfg’r to get the basic alteration approved then simply add other model types to their “approved model list” through a simple FAA process. A PMA process would require a complete FAA alteration approval for each new model or part number.

The Form 337 is used only to record any major alterations/repairs, as defined by regulation, which are performed on the aircraft. Not which design approval was used with the installed part. By using the definition of a major alteration/repair in Part 1 and the descriptions in Part 43 Appendix A, a mechanic will determine whether to complete a 337 or not. But it is his determination that counts.
 
Small update. I pulled the old battery and much to my surprise it was a concorde RG-35AXC in the plane. No where in the logs can I find this entry. Perhaps it's somewhere but not where it should be at least. THe last entry i found was for a Gil G-35 in 2006. I had no idea how old this battery was so I called the good folks at Concorde and they were able to tell me the date of mfg from the bar code. It was July 10, 2008. While I am not sure of when it was put into service I will assume it is quite a few years old. The battery had 12.7-12.8 volts when I pulled it but I had it load tested at autozone (wasn't sure what else to do) and when they tested at the published CCA load of 440A it tested bad. Still not fully convinced this is my problem of a really laborious cranking of the motor but between the load test results and a 9.5 year old battery I figured well worth the investment to order a new one. The people at Concorde are great to talk to by the way. I asked about getting an STC (even though that is what came out of it I wanted it documented correctly) and after filling out a quick form they e-mailed me a pdf of the correct STC within a couple hours. I toyed between the Gil 7035-28 and the Concorde RG-35AXC but after talking to the concorde folks and the fact the old batt lasted at least this long there was no decision to be made, going with a new concorde and see if it solves my problem. Will report back when it gets here. Also for those paying attention my supposed 11 year old Gil from the logs looks to have been replaced in only 2 years or slighly more which seems more believable from what I've read elsewhere.
 
Not all STCs require a Form 337. All depends if it is a major alteration vs a minor alteration.
.
If it isn't a major alteration why would you need an STC to install it?
What is true is not everything that has an STC available actually needs an STC to install. For instance, sun visors I've never understood why they require an STC except in some bizarre circumstances but Rosen has them for a lot of things.
 
Not all STCs require a Form 337. All depends if it is a major alteration vs a minor alteration.

If you USE the STC as your basis for installation, a 337 is required. If it's a minor alteration, the STC isn't necessary at all.
 
Be sure the Gil is fully serviced water-wise.

Be careful. The Gill instructions with the battery tell you to top the cells to the bottom of the split ring while the battery is actively charging and gassing off. If you top them up to the split rings like so many people do, with the battery in the airplane or on the bench but not on charge, it will be overfilled. The next time the battery gets run a bit low during an extended cranking, the charging current will be high once the engine starts. That causes a lot of gassing and heating in the electrolyte, which swells it, and it ends up beyond the tops of the slots on the split rings and is blown out the cap vents. Acid in the box and on the belly, casuing corosion. A "low" electrolyte level the next time the same people check it, so they top it up with water again. This happens repeatedly, the acid gets diluted, and the battery is shot long before its time. I regularly encounter rotted-out battery boxes and ruined batteries caused by this. It doesn't help that "Fill to bottom of split rings" is molded right into the plastic top the the battery. It's misleading.

When the electrolyte reaches the top of the slot in the split ring, the gas can no longer escape and it builds up in the cell, forcing electrolyte up and out the cap vents.

If the battery isn't on charge I will top it so the electrolyte is halfway between the top of the plates and the bottom of the split ring. The plates only need to be covered. Everything above that is reserve, and if the battery is checked once in a while it doesn't need much water.

See http://www.gillbatteries.com/Content/PDFs/flooded_service_manual.pdf and read "Electrolyte Levels."
 
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If you USE the STC as your basis for installation, a 337 is required. If it's a minor alteration, the STC isn't necessary at all.

As I mentioned 4 posts up, a STC has no direct connection to a 337 unless the STC is a major alteration. A STC is not a major alteration on its own but simply a FAA design approval process like a TC, PC, PMA, TSOA, etc. for the part installed. Nothing more. So even if the part you install as a minor alteration only has STC approval, it’s that approval which makes the part eligible for installation in a TC aircraft regardless if you “use” it or not.
 
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Be careful. The Gill instructions with the....

I believe you took my comment out of context as I was not discussing servicing. I was suggesting to the OP he should physically weigh the 2 batteries instead of using the published weights and that he should ensure the Gil had water as it would be lighter in weight when comparing to the Concorde weight. The goal was to see if the weight difference was less than 1lb.
 
@Brian A Johns, I had a recent "pilot deviation" which resulted in our aircraft logs being reviewed. The A&P ASI was pretty cool about things and caught one flub on our part. We had replaced a old headlight with a Prometheus LED head light. When online I thought I found the STC so I referred to the STC in the entry...No-No!...I believe that requires a 337 via IA?? But the ASI said he was positive there was a PMA for these LED lights and said to replace the entry with a reference to the PMA number instead. So that was easy.

Not all PMA parts are plug and play. I believe these lights are "PMA Approved", but as a "Modification", which would still require the approval to install them via the STC.
 
As I mentioned 4 posts up, a STC has no direct connection to a 337 unless the STC is a major alteration. A STC is not a major alteration on its own but simply a FAA design approval process like a TC, PC, PMA, TSOA, etc. for the part installed. Nothing more. So even if the part you install as a minor alteration only has STC approval, it’s that approval which makes the part eligible for installation in a TC aircraft regardless if you “use” it or not.

You're incorrect. An STC, by definition, is a major change. If you use the STC as your basis for installation approval, the modification you've made is automatically major regardless of how small it really is. The STC is the approved data and a 337 is required. If the installing A&P concludes that the modification is minor, the STC isn't necessary at all and need not (and should not) be referenced in the logbook entry.

Source:
"An STC is the FAA’s approval of a major change in the type design of a previously type certificated product."

AC 21-40A (https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC21-40A.pdf)
 
You're incorrect. An STC, by definition, is a major change. If you use the STC as your basis for installation approval, the modification you've made is automatically major regardless of how small it really is.

Not quite. You are applying design approval terms and requirements (Part 21) to aircraft alteration/maintenance requirements (Part 43). They are not interchangeable.

A major change to Type Certificate is not the same as a major alteration to an aircraft. They are two separate and distinct terms. One version of their definitions can be found here:

"A major change in type design can be approved only by an ACO as an amended type certificate (ATC) or Supplemental Type Certificate (STC). A major alteration requires the use of FAA-approved technical data."
http://www.faa.gov/documentlibrary/media/order/8300_16_chg_1.pdf

Major change/minor change to TC only applies in determining if an item needs a STC design approval over say a PMA approval for use on a TC aircraft. If you look at your AC example subject line, it applies only to those trying to obtain an STC not install one.

The STC approval makes an item eligible for installation, not whether it is a major or minor aircraft alteration. So in your minor “mod” example, if you don’t reference the STC in the logbook entry, what design approval allows you to install that item on a TC’d aircraft?

There is no FAA guidance that requires a 337 to be completed based solely on an item having a STC. However, there is guidance that requires a 337 be completed for STCs that meet the definition of a major alteration. Here is one:

“Regarding your first question, reading the applicable regulations together, altering an aircraft in accordance with certain STCs would require completion of FAA Form 337.”

“Therefore, an alteration done in accordance with a STC would constitute a major alteration if it ‘might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness’ or ‘is not done according to accepted practices or cannot be done by elementary operations.’ 14 C.F.R. § 1.1.”
https://www.faa.gov/about/office_org/headquarters_offices/agc/practice_areas/regulations/interpretations/data/interps/2016/bowers%20-%20(2016)%20legal%20interpretation.pdf
 
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