Weight and Balance Changes (Split from backseat removal)

[skippy2]

Bruce, with the W&B sheet doesn't it require an AP to sign it off for anything that is a "static", permanent type fixture? What about removing wheel pants to install 8.00's instead of 6.00's? Need some advice here!


* moderators note: This topic was split from "Taking out backseat" http://cessna170.org/phpBB2/viewtopic.p ... sc&start=0

[Bruce Fenstermacher]

Good question and one I've had for some time but never have not found the answer in the regulations and have not thought to ask someone who might know.

Here is what I believe to be true. The basic act of weighing and calculating the aircraft weight and balance must be performed by an appropriately rated individual. That rating must be higher than a pilot certificate. What I mean is it must be accomplished by someone with an A&P or by a repair station. But I can not confirm this.

A calculated W&B, that is one done using the weight, arm and moment from the actual weighing to adjust for changes to the loading of the aircraft whether that be cargo or equipment, can be done by a rated pilot.

Now lets look at what I'm thinking a bit in detail. You have an A&P remove a radio from your panel. You can't do it with just you pilot rating be he can. He should as part of the removal update the W&B sheet and equipment list to reflect the change. But if he doesn't you should. Actually the work isn't done till the W&B is.

As a rated private pilot and owner under 43.13 appendix A you can remove non structural panels and cowling and fairings. I read that to mean you can remove your wheel pants as long as you don't have to remove structure. Wheel pants are not required for flight per the TCDS so you log the wheel pants removed, adjust the weight and balance and equipment list for the work performed per 43.9.

As a rated private pilot you can remove and reinstall tires. Since 8.00-4 tires are allowed under the TCDS you can remove any tires and install 8.00-4 tires and log the tires removed and those installed and any other work done then adjust the weight and balance and equipment list for the work performed per 43.9.

That is the way I see it and if you want to know what that might be worth read the next line carefully.

[jrenwick]

Part 43 Appendix A item 18 seems relevant: "Replacing wheels and skis where no weight and balance computation is involved" is preventive maintenance that can be logged by a pilot-owner. Changes to the W&B sheet carried in the airplane isn't one of the "PM" items listed in Appendix A, so it seems to me that would have to be logged by an AMT.

I would conclude that removing wheel pants permanently and replacing 600x6 tires with 800x6 would require a W&B change, and so can only be signed off by an AMT.

Best Regards,

John

[Bruce Fenstermacher]

John you are presuming a lot based on one item in an appendix. I did take note of the wheel/ski item but that alone is not enough for me to conclude that a pilot can not change the W&B record.

Tell me what is the difference if I recalculate the weight difference between two different tire sizes or 120 lbs of lead weight I've just thrown in the baggage compartment?

[jrenwick]

Bruce,

1. I can't see anywhere in part 43 that preparing a new W&B sheet is preventive maintenance. That's enough for me to conclude that an AMT has to sign it off (AI maybe? I don't know).

2. If the pilot-owner could certify a new W&B, why would 43-A-18 contain the stipulation of no W&B change?

#2 is a clue, but #1 is the real deal. If an action isn't listed as PM in 43-A, the pilot-owner isn't allowed to sign it off. That's my understanding, anyway.

Best Regards,

John

[Bruce Fenstermacher]

John you may be right but as I said right off it's always been a guestion of mine.

Where is the line drawn. What is the difference between a W&B calculated by an A&P to adjust for a configuration change and the one a pilot does when cargo, passengers and fuel are added?

I think that if you can legally perform the maintenance then that includes, when necessary, an updated weight and balance and equipment list along with the maintenance log entry.

Heck at work our Chart C, which is the historical record of w&b changes from the weighed configuration aren't signed by anybody. Most of the time I guess there is a maintenance sign of elsewhere that might reference the change was made. Our case because we are under 135 that is an A&P but if we flew 91 which is done by many the same functions are done by pilots.

[jrenwick]

Bruce,

As I understand the question, it's about what documents are required by the FAA under part 91. Those are the "AROW" ones:

Airworthiness Certificate
Registration
Operating Limitations
Weight & Balance

Each has to be signed by someone with the authority to certify it. The W&B document gives the empty weight and arm or moment of the aircraft, with specific equipment installed. It requires the signature of an AI as far as I know. If an AMT can do it, then I'm wrong -- but I'm very sure it can't be signed on the authority of a private pilot's license.

The FAA doesn't require the pilot to create a W&B document for the loading on any given flight under part 91. I could create one and sign it with my pilot's license number, but that wouldn't have any legal standing vis-a-vis FAA requirements. It would merely satisfy my own personal requirements.

I don't know about the requirements of operations above part 91, and I wouldn't be surprised if they required the PIC to certify the loading for each flight. But I think the original question was with reference to part 91, and there's no pilot-certified W&B document required there.

Best Regards,

John

[jrenwick]

Heck at work our Chart C, which is the historical record of w&b changes from the weighed configuration aren't signed by anybody. Most of the time I guess there is a maintenance sign of elsewhere that might reference the change was made. Our case because we are under 135 that is an A&P but if we flew 91 which is done by many the same functions are done by pilots.

I'll bet your Chart C keeps track of equipment that's "loaded" on board the aircraft for your operations, not what's "installed" as far as the FAA is concerned. You'd have to do this, because it's too difficult and time-consuming for the pilot to inventory the aircraft before each flight.

As pilot of my own C170 I could do that, but it would be pretty anal, wouldn't it? I just add 10 pounds to the rear passenger weight (tie-downs, oil, spare bulbs & hardware, windshield cleaner under the rear seat) and 3 lbs in the front passenger seat back (Garmin manuals required for IFR operations).

George has more than this, so he may need your Chart C.

John

[Bruce Fenstermacher]

John I said at the very beginning that the weighing of the aircraft and needed to be done by an A&P or better but could not substantiate that.

We are talking changes after the weighing for what ever reason. Like say you the pilot removes your rear seat which you are aloud to do. I believe you can adjust the w&b and and equipment list in this case in fact you are required to do so.

Our Chart C is not for equipment loaded but equipment installed. But we could put equipment loaded on it if it was equipment that would always be found in the aircraft . For example the patient litter is sometimes found on the Chart C and sometimes it's not.

And your right the FAA does not require an actual w&b to be performed before flight under 91 but it does require the pilot to know the W&B of his airplane in flight.

But under 135 with 2 or more engines a w&b and load manifest for each leg is required before each flight. Yes we are required to inventory all cargo and passengers as well as any other changes and calculate the w&b and create a load manifest all while the aircraft is running in a corn field in the middle of the night as the crew is loading the patient that might be coding, into our aircraft. We medevac pilots do this calculation, which must be kept for 30 days and is inspectable, all the time as a matter of normal business.

[jrenwick]

You have a very challenging job, Bruce. A lot of satisfaction must come along with that.

Interesting question about taking the seat out. I suppose a pilot could weigh it and perform a W&B calculation using a negative weight in the passenger seat position, but to be strictly legal it seems to me an AMT would have to do a revised W&B sheet for the airplane. I'll ask an IA about that. Seems like you could keep two W&B sheets in the airplane, one for use with the rear seat in, the other out.

My IA gave me three authorized W&B sheets to keep in my Cub: one for floats, another for wheels, and the third one for skis. As pilot-owner, I'm allowed to change between wheels and skis and sign that off each time. It involves a W&B change, but I just use the empty weight and arm from the appropriate document.

[GAHorn]

FAR 43, Appdx A, Item A, subpara (xi) lists as a major altration "Changes to the empty weight ..." (such as a seat removal for flight) which requires an "authorized person" such as an A&P, IA, Repair Station, or Manufacturer to approve the aircraft for return to service.
Removal of seats for reupholstery is a preventive mx item, but removal of a seat is an alteration of the aircraft specifications and requires a new wt and bal, equipment list, and approval for return to service. A common method for operators/owners to accomplish this is to have Form 337's completed and approved by such persons (mechanics/etc) and carried onboard. A wt and bal may be "certified" or "attested" to by the owner of the aircraft, who is ultimately responsible for the airworthiness of the aircraft. IMHO

[Bruce Fenstermacher]

Ahhhh now we're getting somewhere "official" in this discussion. I'll review this and get back.

[jrenwick]

....A wt and bal may be "certified" or "attested" to by the owner of the aircraft, who is ultimately responsible for the airworthiness of the aircraft. IMHO

Does the FSDO agree?

John

[Bruce Fenstermacher]

After review of the FAR George quoted I find that it does not apply.

Here is the FAR part in its entirety:

43.13 App A (a)(1)(xi) Changes to the empty weight or empty balance which result in an increase in the maximum certificated weight or center of gravity limits of the aircraft.

It does not apply because installing 8.0-x tires over 6.0-x tires or removing the rear seat does not "result in an increase in the maximum certificated weight or center of gravity limits of the aircraft."

So we are back to square one. I may not be right but I've yet to be shown to be wrong via the FARs.

I've quizzed two IAs about this since the start of this discussion. Each had the same initial reaction that at least an A&P was required but they could not tell my where it said the in the FARs. After further discussion each conceded my argument had some validity. Both suggested to just make the changes ie seat removal and tire change without changing the w&B and no one would no the difference. Of course that is NOT the answer I'm looking for.

The search for the answer continues.

[GAHorn]

Bruce, I disagree (respectfully, of course.) The key portion of the phrase is "Changes to the empty weight OR empty balance ..." Since removal of the seat changes the empty weight, it is a major alteration. A change involving a change in empty balance OR center of gravity would also apply. The removal of the rear seat does change both empty wt and CG.
Additionally, the aircraft specifications are listed with FAA by the mfr. This aircraft was certificated as a 4PCL airplane and left the factory with a rear seat (see the equipt list) that must be installed...or documented by an authorized person... to remain airworthy. Similarly, if a radio is removed, prior to flight the wt/bal, logs, and equp. list must be amended, and the removal must be performed by an authorized person. Neither is preventive mx, and therefore cannot be performed by the owner/pilot.
In other words, removing the rear seat to reupholster it (and subsequently reinstall it) is preventive mx and may be performed by the owner/pilot. But removal of the seat, not intending to reinstall it for flight, is not preventive mx and may not be done by the owner/pilot.