I'm looking for some sort of FAA FAR or AC or anything related to the legality of adding ballast to an airframe to get a more desirable empty CG. I've always heard it's legal to do so but was hoping to find something in writing. Anyone know where to find this?

Thanks,
Asa

43.13-1B 10-22

Take care, Rob

Water container?

Rob wrote:43.13-1B 10-22

Take care, Rob

Of course the ag guy would have this memorized.

Follow-on question: If something is described in AC 43.13-!B, does that make it legal for all certified aircraft? It describes the proper technique for effecting such a modification, but is anything else required to make it legal as a mod for a given type?

Thanks, Rob. That's what I found too, but I was hoping there was something worded more like clear regulation. This paragraph uses "often" and "sometimes" and sounds more like a survey of industry practices more than a rule. But I guess that's all there is haha. The two bold lines do sound more like rules - placarding and investigating strength. So maybe that's the only requirement. Whatever "investigating" means.

10-22. INSTALLATION OF BALLAST.
Ballast is sometimes permanently installed for c.g. balance purposes as a result of installation or removal of equipment items and is not used to correct a nose-up or nose-down tendency of an aircraft. It is usually located as far aft or as far forward as possible in order to bring the c.g. position within acceptable limits with a minimum of weight increase. Permanent ballast is often lead plate wrapped around and bolted to the fuselage primary structure (e.i., tail-post, longerons, or bulkhead members). Permanent ballast invariably constitutes a concentrated load; therefore, the strength of the local structure and the attachment of the ballast thereto should be investigated for the design loading conditions pertinent to that particular aircraft. Placard permanent ballast with Permanent ballast - do not remove. It is not desirable to install permanent ballast by pouring melted lead into the tail-post or longerons due to difficulties that may be encountered in subsequent welding repair operations. It should be noted that the installation of permanent ballast results in an increase of aircraft empty weight. See figure 10-19 for ballastcomputation. The local strength of the compartment in which the ballast is carried and the effect of the ballast on aircraft weight and balance should be investigated when disposable ballast is carried.

A review of the FAA Weight and Balance handbook will have you changing your question from 'do I need permission to install permanent Ballast'
to 'am I going to be required to install permanent ballast'.

FAA-H-8083-1B

Take care, Rob

Zzz wrote:

Rob wrote:43.13-1B 10-22

Take care, Rob

If something is described in AC 43.13-!B, does that make it legal for all certified aircraft?

Yes and no. It is acceptable data not approved data. Boiled down version ; for Mx and minors yes. If it takes a 337 (major repair or alteration), it's a good start, but you're going to need more.

Take care, Rob

I think it is now approved data. So because of the weight increase not to mention changes in how it flies would it be considered a major alteration ?

https://www.shortwingpipers.org/forum/s ... roved-data

Wouldn’t Maule be the first place to ask?

This is always a good question, usually ending up with folks tossing around home spun theories, but no one ever coughing up a solid basis other than "well that's the way we do it."

The problem with ballast isn't where it will go, or how much, it's HOW it gets attached... technically one cant just drill holes, attach brackets, pour lead etc etc. These birds are pretty cleverly engineered, and without more engineering, we don't know the repercussions from the backyard expert just "adding" a bunch of weight were it wasn't meant to be. Yeah it'll do what they want it to do, and it might be fine... but then again?

I'm not sure of the "correct" answer... i've looked and looked, but never found black type saying, yes... on this airplane, do this.

Good thread though.

Bigrenna wrote:This is always a good question, usually ending up with folks tossing around home spun theories, but no one ever coughing up a solid basis other than "well that's the way we do it."

The problem with ballast isn't where it will go, or how much, it's HOW it gets attached... technically one cant just drill holes, attach brackets, pour lead etc etc. These birds are pretty cleverly engineered, and without more engineering, we don't know the repercussions from the backyard expert just "adding" a bunch of weight were it wasn't meant to be. Yeah it'll do what they want it to do, and it might be fine... but then again?

I'm not sure of the "correct" answer... i've looked and looked, but never found black type saying, yes... on this airplane, do this.

Good thread though.

Seems like no matter where you look, it's the FAA saying "Yeah this is something that's done" rather than "this is something that you can or can't do."

Cuffed wrote:Wouldn’t Maule be the first place to ask?

I meant this as a general inquiry that could be applied to all types. If I was only worried about my Maule I can just pull up the ballast drawing in my Maule drawing index. With this it's just a logbook entry. "Added ballast weight per Maule drawing 1301B Rev B". It's good to own a moll

An owner builder can do anything they want or dream about to an experimental. Wouldn't anything that requires a 337 or physical attachment to a non-experimental require log book entries and a A&P signature?

PapernScissors wrote:An owner builder can do anything they want or dream about to an experimental. Wouldn't anything that requires a 337 or physical attachment to a non-experimental require log book entries and a A&P signature?

There’s a lot here to unpack, could be a thread in itself. Physical attachment is a very loose term so I’d say that doesn’t mean much. 337 forms, logbook entries, and A&P signatures are all necessitated in varying circumstances. My question (presumably as well as Rob and Greg’s responses) were predicated on meeting the logbook, W&B entry, and A&P signature portion of this. The necessity of a 337 (which is only required for a major repair/alteration) for adding ballast is unclear to me.

No,

I *think* agree, with most if not all of Greg's post.

I also *think* it's pretty clear, just one of the more often 'humanized' components in maintenance. By humanized I mean like when you see the speed limit is 75, but you do 80 because it seems reasonable and prudent. Unfortunately (in most cases) that just doesn't make it right. I typically do 82

The point in my posts was for your Maule, because like my beloved Turbo Thrush' there are designed provisions to do just what you ask. This is not uncommon by the way, and then since it is in the TCDS, Maintenance manuals etc, it is our 'legal' path. The handbook alludes to this, perhaps the initial version was written in a day when common sense was more common. I feel like asking for more clarity often just leads to more regulation.

Another common example is the STC'd modification that requires an alteration to get the CG back to specs. Again there is engineering, and again not uncommon. And once more our legal path is pretty clear.

The next example would be that of, oh, let's say an amphib that falls out of CG. We are now burdened with the task of making it 'in' CG. And let's say we can achieve that by fixing some ballast in the rear of the baggage area in an amount that does not exceed the load design of the baggage area. Now we again are operating within the engineering of the aircraft, Why the paint and placards? because in this case, that ballast is required as long as that aircraft is in that configuration. Why permanent? because these are generally configurations that are not coming and going every other day.

I think the 'rub' is when humans intervene... This is when Joe blow say 'hey, my lawn dart flys like shiv and I see Jim's steam Belaire conversion has lead in the tail post. I can add 50 lbs of gold bullion to my baggage area and be legal, but why don't I just pop rivet a few fishing weights to the tail and get the same CG effect"

It's what we humans do...There are many definitions within the FAA that are clear as mud, but I don't think going off the reservation with engineering or design load changes is that murky.

All of this is but my opinion, I'd love to hear what some of the more experienced IA's on board have to say about the matter. Like pilots, rare is the mechanic without 'opinion'

And lastly I, like MTV, am all for no ballast. Most of us are not flying gliders in the back country. Many but not all of us understand a sweet flyer requires a sweet CG. In our realms and with the tools available to us, barring a really poor configuration, there is almost always a better (but maybe not cheaper) way than lead....

Take care, Rob

I asked the question a few posts back because I used to work with an owner/modifier of a production aircraft that he and his brother owned. We got to be pretty good friends and talked a lot about his plane and flying.

One day the two brothers got their heads together and decided the plane would fly so much better if they moved the battery from in front of the firewall to aft of the rear baggage compartment bulkhead. Sure nuff the plane flew faster and controls were lighter. Thing was, the plane was certified for spins. With the battery up front... One day the brother decided to do one of those approved spins. My friend said it rapidly went flat and his brother died in the resulting crash.

What I got out of that was we gotta really know our stuff if we move design weight around. Moving that heavy battery was something the brothers should've run by a DER, or at the very least, a really GOOD A&P who could've caught their error. If we're just playing with W&B within the confines of the design envelope then 'ballast' is just a penalty on useful load. Load however you want within that envelope. And if the envelope splits between utility and whatever, that's fine too. We just have to play ball according to the design limitations of whichever envelope we've loaded for.

Not an engineering observation but I do fly a Maule:

Since I have a 4 cylinder Maule I would assume that very little is needed in the way of aft ballast as a result of the lighter nose. Maule's have heavy tail wheels compared to other tail wheel aircraft (about 175 lbs without any load). With that kind of weight, you'd think that ballast was unnecessary. But the angle of incidence in the main wing and the horizontal stabilizer are the primary factors in this balance during flight. With my payloads starting out loaded directly behind the front seats (the back seat has been removed for years as I carry more cargo than not), it causes a nose up trim setting to maintain level flight. If I toss some of the heavier items to the rear bulkhead during flight, it relieves the deflection on the elevator and I can gain 8 mph in cruise.

I'm thinking that in order to maintain the flexibility of operating the aircraft with the full envelope of designed loading, permanent ballast would limit some of your loading configurations. If I'm flying light, I just keep about 40 lbs of "stuff" against the rear bulkhead to increase efficiency. Maules are designed to carry a lot of stuff for their size and weight and have a wide loading envelope.

But since you have made numerous changes/improvements to your aircraft and not made changes to the wing angles, its conceivable in your case that ballast would be necessary to return the aircraft to it's designed CG envelope.

.

Just so no one gets confused with the terms. Ballast is different from normal load or equipment. Survival gear/ food/camping gear/people while all can effect the CG are not considered Ballast. Ballast is EXCESS weight secured to the aircraft that has no other purpose than to effect the CG of the plane. It will also reduce the useful load of the aircraft!! I point this out because new pilots or others may confuse the terms thinking that adding an extra 70 lbs of lead in the rear baggage while keeping other gear more forward in the plane would help it fly better. and not consider the negative aspects. Aircraft with a fixed stabilizer are at a disadvantage when it comes to load placement and ability to easily adjust for variance in CG, that is whey its is important to understand the effects of load placement including the dangers of aft CG. I would say not a big deal but how legal/correct is it to add Ballast to tail of a aircraft with a logbook entry like most things correct or not it depends on your IA and the local FISDO. If you are going to use gear of cargo to effect the CG then use that terminology not Ballast. It can be both confusing and dangerous to both new and older pilots that do not understand the difference.
DENNY

Zzz wrote:

Follow-on question: If something is described in AC 43.13-!B, does that make it legal for all certified aircraft? It describes the proper technique for effecting such a modification, but is anything else required to make it legal as a mod for a given type?

Subject: ACCEPTABLE METHODS, Date: 9/8/98 AC No: 43.13-1B TECHNIQUES, AND PRACTICESAIRCRAFT Initiated by: AFS-640 Change: 1 INSPECTION AND REPAIR
1. PURPOSE. This advisory circular (AC) contains methods, techniques, and practices acceptable to the Administrator for the inspection and repair of nonpressurized areas of civil aircraft, only when there are no manufacturer repair or maintenance instructions. This data generally pertains to minor repairs. The repairs identified in this AC may only be used as a basis for FAA approval for major repairs. The repair data may also be used as approved data, and the AC chapter, page, and paragraph listed in block 8 of FAA form 337 when:
a.
the user has determined that it is appropriate to the product being repaired;
b.
it is directly applicable to the repair being made; and
c.
it is not contrary to manufacturer’s data.

Several years ago, I owned a Rockwell Commander 114 that has an STC'ed turbo-normalizer. It was a great airplane, and the TN addition was MUCH simpler to operate than the full-on turbocharged engine, where you had to manage the MAP to stay within limits. TN was "set it and forget it" for the most part.

However, the one drawback was that the added weight of the turbo system way up on the nose meant the airplane's CG was a bit forward. Even with just me in the plane, the CG was forward of the limit. Fuel was pretty much on the CL, so it made little difference to the CG. Because I'm a heavy guy (more so at the time...), I needed to keep a fairly heavy toolbox strapped down in the baggage area to be comfortably within the G limits - especially if I flew with another pilot. Back seaters were behind the CL, so they reduced the need for ballast, but 99% of my flying was solo or with one pax.

So I approached my mechanic (who is an IA) about the possibility of adding some ballast somewhere in the back of the plane to simplify the load profile. We looked into it, but the Commander is aluminum skins over bulkheads construction. Thus there was no easily identifiable place in the tail with sufficient structural strength to support the weight of ballast. Ideally, we would have liked to put the ballast way back in the tail, where the "lever" effect would mean less weight was required (so increase in empty weight, and less reduction to useful load).

After discussing this with the FSDO, my IA said they would require a DAR sign-off (engineering study) for them to approve adding ballast to any structure in the tail. I had a brief conversation with a DAR they recommended, and he said he would not even accept the work request, because any significant amount of ballast that far back would completely change the behavior of the airplane in a spin. He was concerned about the potential to enter a flat spin that would be unrecoverable. So he basically said "Nope! Not willing to risk my DAR certificate for that..."

He did, however, point out that there was an aft avionics bay that WAS engineered to support old-fashioned avionics, which were quite a bit heavier in the '70s when this plane was designed, and that it would likely NOT require DAR approval for the FSDO to approve. So we looked at that possibility, but soon realized the only suitable location was immediately aft of the baggage compartment, and the amount of weight required for ballast would be only about 10 lbs less than what was required in the back edge of the baggage area. Plus it would have the disadvantage of being "non-removable" if I even flew somewhere, and returned with an extra passenger (or two), or some "heavy shopping" to carry home.

Ultimately, I bought a couple of lead bars, and strapped them down with heavy-duty strapping at the very back edge of the baggage area. I listed them on my W&B sheet as "baggage @ station xx" and called it a day.