GTOW

[JJ Campbell]

In the US my Tecnam P92 Eaglet as an LSA has a max gross weight of 1320 pounds (600 Kilograms). I've been told that in the EU the same plane has a higher weight limit. Is this true? If yes, does anyone know what it is?

[Warmi]

In the US my Tecnam P92 Eaglet as an LSA has a max gross weight of 1320 pounds (600 Kilograms). I've been told that in the EU the same plane has a higher weight limit. Is this true? If yes, does anyone know what it is?

Not sure about this particular plane but there are quite a few LSAs out there with varying gross limits across different markets
For instance Sling 2 , if build as EAB has a max gross limit of 1549 lbs while still being limited to 1320 lbs if build as an LSA plane.
https://www.airplanefactory.com/aircraft/sling-2-kit/

Same thing with Jabiru 230d planes ..

It is nice to know that you have some margin of safety build into the plane but I wouldn’t plan my flights around that fact ...

[drseti]

Many European manufacturers like to point out that their aicraft are certified above 600 kg in other countries, and can "handle it." What they're not telling you (but you should know) is that stall speed goes up with weight, so if overloading an LSA (even in countries where it's legal), you are actually reducing your safety margin.

It is nice to know that you have some margin of safety build into the plane

Or a built-in margin of hazard, depending upon what the pilot decides to do with it. Don't be sucked into this trap!

[Wm.Ince]

. . . . . For instance Sling 2, if build as EAB has a max gross limit of 1549 lbs while still being limited to 1320 lbs if build as an LSA plane.

It is nice to know that you have some margin of safety build into the plane but I wouldn’t plan my flights around that fact ...

Actually . . . MTOGW of Sling 2 EAB is 1,540 lbs . . . not 1,549 lbs.
Concur with your point about "margin of safety build."
I personally really like the Sling 2.

[fatsportpilot]

Many European manufacturers like to point out that their aicraft are certified above 600 kg in other countries, and can "handle it." What they're not telling you (but you should know) is that stall speed goes up with weight, so if overloading an LSA (even in countries where it's legal), you are actually reducing your safety margin.

Not just that, but it also means high G forces are more stressful on the aircraft. Your Va and Vne would probably also change. It's true that a plane can usually safely take off and land with more weight than it should (like a ferry permit that might let a Piper Cherokee fly 1000 lbs overweight) but only if nothing goes wrong. If you are 2 lbs over then there's nothing to worry about. If you're 20 lbs over then stall speed will change a little. If you're 200 lbs over then even though it would be safe in theory, but if you get into a spin and recover and pull up at Vne then the G forces might be so much that it could snap the tail right off, but it wouldn't if you weren't overweight.

Dealing with a higher stall speed is easy and just takes some training. But no amount of training can help you if you can't recover from a dive without breaking up.

[designrs]

CG also needs to be considered in the entire envelope from full tank to empty. Some aircraft can have a really rearward CG when fuel is low and passengers are heavy, not to mention luggage. If the plane is at the limits for rear CG it could be much easier to get into a flat spin which is harder to get out of and certainly would be tragic at low altitudes. I know someone that this happened to. Fortunately they were at altitude, but it wasn’t easy to get the nose down for spin recovery. They actually had to lean their bodies forward!

I often wondered about some aircraft with sliding seating positions too. I’m sure that it is factored into the CG envelope but it’s something to think about especially when approaching limits.

[drseti]

CG also needs to be considered in the entire envelope from full tank to empty. Some aircraft can have a really rearward CG when fuel is low and passengers are heavy, not to mention luggage.

This was indeed the case with my Bristell taildragger. Even before I bought it, I spent many an evening crunching wt/bal numbers, and discovered there was a problem - even if properly loaded before flight, the CG could quite easily shift back to outside the rear envelope limit when fuel got low. We re-weighed the plane as soon as I acquired it, and I confirmed the problem had only gotten worse with the addition of autopilot and ADS-B.

Working closely with the factory and the importer, I did a redesign that involved installing two ballast counterweights onto the prop gearbox. This cost me a bit of useful load (the carbon fiber fuselage made the plane very light, but that exacerbated the loading problem). I wrote an LoA which the designer signed without hesitation, and the importer had the weights manufactured by a local machinist, and installed them for me.

I created an Excel workbook to analyze CG everywhere from full to zero fuel, at max load, max forward loading, and max rear loading. It can be found at http://avsport.org/acft/tdo.htm, and is now provided to all Bristell owners (they just have to plug in the arms and weights for every station of their particular plane).

The reason fior two separate ballasts at two different locations is to make mine a universal solution. Depending on the plane, owners can install just the heavier weight, or just the lighter one, or both, as required to make the sensitivity analysis work out. At least one other Bristell is in the shop right now getting this mod - hopefully, the project will make the whole fleet safer.

Oh - and the plane handles beautifully with the weights installed!

[drseti]

(Duplicate deleted)

[designrs]

Nice. You’re the expert Dr. Paul! Most people don’t look closely enough at these things. The point being that safety a lot more than just Gross Weight.

[designrs]

Shortly after purchasing my plane, I saw Dr. Paul for my first annual. My aircraft was near new, very well maintained with “good” documentation. Dr. Paul called attention to an upgraded prop which was actually installed on delivery to the first owner by the distributor. At the time, it wasn’t clear how it was accounted for in weight and balance.

Being a new owner, I was really overwhelmed when Dr. Paul mentioned the possibility of having to weigh the aircraft. I’m a gearhead but everything about maintence documentation took time to get my head around. While I fundamentally understood weight and balance as required for a pilot, I didn’t really understand the implications of CG in terms of experience... and how slim that CG envelope can be under changing conditions.

Fortunately we were able to make a few phone calls and get an updated weight & balance from the manufacturer who was now installing the new prop as standard equipment.

In retrospect, it would not have been a big deal to weigh the plane.

[JimParker256]

My current E-LSA (RANS S-6ES) is the 4th airplane I've owned. I read through the W&B document file that came with each of those airplanes, and found some pretty egregious math errors in every single one of them. Hard to believe, but A&Ps are no better than the rest of us when it comes to making errors in simple addition and subtraction.

When we weighed those planes, not one of them weighed what the W&B forms indicated. One was almost 150 lbs heavier that stated, in part because a turbo-normalizing system had been installed (turbo, new exhaust, controller, etc.) and the entry stated that the weight of all that "stuff" was less than the simple exhaust that was removed... (A physical impossibility!) This was a fairly obvious error that went "unnoticed" for 7 years before I bought it...

My Citabria weighed exactly what the W&B form stated, but the empty moment (and therefore CG) was off by a significant margin - like 6 inches! The error erroneously pushed the CG aft, and appeared to cause otherwise normal loads (anyone over about 50 lbs in the back seat) to show as being well aft of the rearward CG limit. That error was apparently caused by weighing the airplane with the tailwheel on the ground, instead of in a level flight attitude, as specified in the Maintenance Manual for the airplane. After we corrected that error by weighing the airplane in the proper attitude (weight didn't change, but the distribution certainly did!), I could have a 200 lb passenger in the back seat, and still remain well within the limits.

My current E-LSA had several modifications done at the time I purchased: we added a 2.75 gallon header tank, added a uAvionx echoUAT (ADS-B In/Out system) and a new altitude encoder, the worn-out tires were upgraded from 6.00x6 to 8.00x6, all the engine fuel and oil hoses were replaced with the new "permanent" teflon-type hoses, and we installed all new Gates Barricade fuel lines (versus the brittle, ethanol-hardened "blue plastic" fuel lines that were originally used). All these changes added weight, and rather than "guess" at the new weight and CG, I had the plane weighed. Guess what? It weighed LESS than the estimated changes based on parts removed versus parts installed. I can only conclude that the original weighing was done with scales of rather questionable accuracy...

Some people have accused me of being an idiot for having my planes weighed, because they say it cost me useful load since all of them (with the one exception) were heavier than the W&B forms indicated (one by quite a bit). But to me, the real useful load did not change at all... It's just that before weighing the plane, I had no idea what it really was... For instance, had I loaded four adults into my turbo-normalized Commander, even though I would nominally have been "below gross weight and within CG" according to the W&B documentation, the reality is that I would have actually been at least 150 lbs above max gross weight, and (more importantly) almost 5 inches FORWARD of the forward CG limit. At the end of a long flight, with low fuel load, the CG would have been far enough forward that it might well have been impossible to rotate the nose into a landing attitude – the perfect recipe for a prop strike and/or nose gear collapse.

Finally, until I began researching W&B on production airplanes, I had no idea that the FAA allows the manufacturer to weigh only about 10% (sometimes less) of the airplanes that come off the production line. If the airplane they weigh is within a certain margin of error versus the average of the preceding production output, no changes to the claimed empty weight need to be made. And even if it does turns out that the newly manufactured airplane weighs more than the magic percentage over the "norm", they average the new weight with the old assumed weights (using FAA logic rules) to come up with a new "fleet average" weight for new planes going forward. One well-known Grumman "Guru" weighed every new plane they received from the Grumman factory (over 40 airplanes over a multi-year period), and 100% of them weighed MORE than the claimed "empty weight" from the factory - some by as much as 50 lbs.

I think it's a really good idea to weigh your airplane, so you will know what your REAL useful load and CG ranges are. It could mean the difference between life and death in some load configurations!

[3Dreaming]

I agree with the math errors just saw some on a Piper Pawnee W&B. I have also found that it is a good idea to measure the the points you are weighing. On a few old tailwheel airplanes I found the distsnce to the tailwheel is different than in the TCDS.

[ShawnM]

I also agree with Jim, weight your plane so you KNOW what your weight and balance REALLY is. I did several modifications to my SportCruiser after I converted to E-LSA and therefore had to weight my plane. I wanted to know exactly what I was dealing with and where my CG was. The heaviest mod was adding autopilot to my plane. Most mods were upgrades so something came out and something went back in of similar weight but never exactly the same. Could your plane be lighter, sure, if you rip out a ton of steam gauges and install todays latest glass you'll be lighter and can increase your useful load. Don't you want to know by how much? Weigh your plane, it really is a great learning experience if nothing else. Math is fun.

I then created a great Excel spreadsheet formatted to my iPad mini that has a graph that shows me at a glance exactly where I am given what's on board. I even included fuel burn so it would calculate the landing CG so I know where I am after I burn off 11 gallons during the flight. Call me crazy but I think W&B is critical and I want to be sure I'm never outside my envelope at any given time.

Do you know what your plane weighs? Willing to bet your life on it?