Increase in Registered Gross Weight?

[Jesse]

Originally Posted by Mel

The FAA/DAR can deny airworthiness certificate for any reason they consider unsafe. If you have increased the gross weight from that established by the designer, the inspector may require engineering data to justify the weight increase.

How many have you denied because of this?

[Mel]

Originally Posted by Jesse

How many have you denied because of this?

I have never denied one for this reason. However I HAVE required engineering data.

[Walt]

Originally Posted by RV7A Flyer

First, just make it Normal Category above 1800 and below your chosen max gross...that's -1.5 to +3.8. Utility between 1600 and 1800, Aerobatic below that. Simple.

Second...what's the ID placard got to do with it? You only need 3 things on that...Builder, Serial Number and Model. Anything else is not required, so why put it on there?

The above is what I did as well but years after the initial airworthiness was issued. For simplicity sake I would suggest you initially certify the aircraft at the recommended 1800 then go back later into phase one and and increase the GW.

Oshkosh is my "heavy" trip and I wanted to keep it "legal" for that once a year excursion where I could exceed the 1800 for a bit.

[Mel]

Originally Posted by Walt

For simplicity sake I would suggest you initially certify the aircraft at the recommended 1800 then go back later into phase one and and increase the GW.

This makes it simpler for everyone.

[Snowflake]

Given how quickly discussions of accidents are shut down, at least partly due to liability concerns, i'm amazed threads about increasing gross weight aren't shut down just as fast. The liability issue has to be just as strong in these.

[JonJay]

Anybody know of any RV accidents that the probable cause was operating above gross weight?

[mikerkba]

Not advocating one way or the other...
I wrote up my RV7A (2009 inspection year) with a gross weight of 2000 pounds in normal category (knowingly not consistent with Van's specs), 1800 (factory recommended gross weight) for utility category, and 1600 (factory recommended gross weight for aerobatic category). The inspector (a long-time FAA-designated DAR in multiple categories from experimental Amateur Built to Jets) had no issue with that when we specifically discussed it. The airplane was successfully inspected and letter issued that day.

[kbalch]

This all boils down to rationalizing a gross weight increase (without any supporting engineering data - back-of-envelope pseudo-calculations notwithstanding) for the sole purpose of convenience. The point that doing so, if one can squeak it past the DAR, makes the operation legal is entirely irrelevant.

It pays to remember (in all sorts of contexts) that having the right/ability to make a choice doesn't render any choice one makes safe, sane, or intellectually defensible. To say nothing of judgement-proof after the fact.

Better by far to stick with the kit manufacturer's numbers. If one really can't fit one's flying requirements within those figures, even if only occasionally, then the airplane in question is simply not right for the mission.

[David Paule]

One problem with raising the gross weight is that the landing gear may no longer be strong enough. It's based on how much weight is on it, not on whether the plane is being flown at a reduced load factor. And without a series of drop tests, you won't know.

Another is whether the forward and aft CG limits are still realistic. This can only be determined by flight test.

Still another is determining the take off and climb and landing distances and speeds - and lets not forget the other speeds, which are affected by the weight.

Dave

[Xkuzme1]

I changed my Ops limits to give me 100 more weight for takeoff weight but my landing weight stayed the same. Max weight for GA airplanes is usually predicated upon landing and not takeoff.