Changing gross weight with the FAA...

[DBVZ]

Is it possible to change the weight when you change the wings, for a non-builder owner? The different wings allow higher weights when building, but how do you do it later as a non-builder owner? And if the builder can set the max gross even higher than the kit MFG suggests for a particular wing, what can a non-builder owner do if he makes a "major modification" and submits the resulting new W/B to the FSDO?

[jtpitkin06]

Yes, you can increase the gross weight as an owner. It is considered to be a major modification just as changing the wings to a different airfoil or structure.


Refer to the operating limitations. It will tell you what to do in the event of major mods. Typically, you will notify the FAA, do new weight and balance forms, and re-enter the Phase 1 flight testing. You will be assigned a flight test area and need to fly off the hours. Probably 5 hours at max. You will make the appropriate logbook entries and then you are good to go.


Not really too complicated. But it is doable.


One additional note: If you increase weight above 1320 pounds, the aircraft may NEVER go back to LSA; even if you declare a future gross weight under 1320. The rule is clear. If an aircraft has EVER been operated outside of LSA then it may never be certified or operated as LSA.
Where some people get stung is putting on an in-flight adjustable prop. That automatically bumps you out of LSA forever, even if you later take it off. If it’s in the log… it’s history.


John Pitkin
Greenville, TX

[akflyer]

On what form do you submit the "gross weight" of your aircraft to the FAA?? Just curious cause there is nothing in the FAA files on several of the planes we fly localy that states anything about a "gross weight" ?

[DBVZ]

The one I am aware of is the W/B that the DAR signs off when you submit the program letter to go into flight testing. Not sure where that goes, but it is where the CG limits and gross weight are set, or so I was told. It does not show up on the AW cert or registration. My question was about if a "major modification" and a new flight test period of 5 hours (with a new W/B for the flight test) would work to change it. Seems like it does, even for a non-builder owner, if John Pitkin is right. Makes sense to me.

The next question is if the MFG plate on the tail gets changed too. Seems like it could be a ramp check problem, though you would have a more current W/B to show.

[akflyer]

If you get ramp checked, just have your latest W/B form and you should be good to go. When the FAA inspector came down and looked at my plane due to a "lost AW cert" (the original burned up in a house fire so said the original owner) he glanced at the paperwork I had put together for the total rebuild on the plane. He never looked at nor signed off on the W/B. I dont see any reason for them to do so. Then again, different FSDO's seem to do things MUCH differently and there is no real consistancy across the states. Maybe I just got real lucky to have a very nice guy come down and check my plane out. Too bad he retired a couple months after he handed me my pink slip.

[DBVZ]

If I understand you correctly, it becomes a performance issue rather than a structural issue and may depend on the HP of the engine. Something that could be determined during a 5 hour flight test program as part of a weight change "major alteration"?

[t j]

There seems to be some confusion on where a specific Kitfox's maximum gross weight is documentated. Here's my take on where it can be found.

My operating limitations contain this paragraph:
"...Following satisfactorycompletion of the required number of flight hours in the flight test area,the pilot must certify in the records that the aircraft has been shown to comply with 91.319(b). Compliance with 91.319(b) must be recorded in the aircraft records with the following or a similarly worded statement. "I certify that the prescribed flight test hours have been completed and the aircraft is controllable throughout its normal range of speeds and throughout all maneuvers to be executed, has no hazardous operating characteristics or design features, and is safe for operation. The following aircraft operating data has been demonstrated during the flight testing: speeds Vso____, Vx____, and Vy____, and the weight_____ , and CG location_____ , at which they were obtained."

Now, being that V speeds and Vso by definition for an aircraft are determined during flight testing at maximum gross weight, there you have your maximum gross weight required to be recorded right there in your aircraft's log book.

[DBVZ]

The following aircraft operating data has been demonstrated during the flight testing: speeds Vso____, Vx____, and Vy____, and the weight_____ , and CG location_____ , at which they were obtained."

Now, being that V speeds and Vso by definition for an aircraft are determined during flight testing at maximum gross weight, there you have your maximum gross weight required to be recorded right there in your aircraft's log book.

You would think so, and perhaps that is what the FAA intends and expects. But the Avid Mk IV I mentioned with 1320 on the data plate shows test flights were done at 1070. All signed off by the DAR with 1320 listed as max gross on the top of the official W/B, even though the most forward, aft, empty CG calculations are all at lower weights. Go figure. BTW, the Operating Limitations I saw for that plane seems to have been signed off with those items blank, for the builder to fill in. DAR not doing his job? Or builder not doing his? Or both?

Also, the Operating Limitations are not in the aircraft log book are they? Need to be carried in the aircraft, and the log books are not.

[jdmcbean]

Yes, you can increase the gross weight as an owner. It is considered to be a major modification just as changing the wings to a different airfoil or structure.
Refer to the operating limitations. It will tell you what to do in the event of major mods. Typically, you will notify the FAA, do new weight and balance forms, and re-enter the Phase 1 flight testing. You will be assigned a flight test area and need to fly off the hours. Probably 5 hours at max. You will make the appropriate logbook entries and then you are good to go.
Not really too complicated. But it is doable.

Just a reminder that while the non-builder/owner can do the maintenance it does require an A&P to sign off the work. Also, you may be asked by the FSDO to substaniate the changes. The Data plate should not be changed.. It is actually against the regulations to remove the data plate.

While a ramp check will typically only look at the documents in the aircraft or on-hand and available they can request to see all the log books and other documents. Also, if there is an incident or accident you can be assured that all the documents will most likely be looked at either by insurance, FAA or NTSB.

[DBVZ]

I flew a Kitfox V where the builder did the same. The W/B the DAR saw was 1320, but nothing on the data plate. Most builders fill it in though, so as a subsequent owner you deal with what you have. 1320 W/B on a V that was designed for 1550 is one thing. I also saw an Avid IV with 1320 on the W/B the DAR saw, and 1320 on the data plate. HH wings that are usually considered 1150, though often increased to 1200 or 1250 with floats just because.