Sport Pilot Talk

saintlfd · Joined: 17 Jul 2009 Posts: 47 Location: ARGYLE, TEXAS

Is it simply one of the dirty little secrets of LSA's that pilots routinely exceed MTOW?

I am a student sport pilot and have been surprised at the nonchalant attitude of various instructors, salesmen and other pilots as they 'suggested' that such-and-such LSA would fit my needs (two full-sized adults plus bags for a long weekend) since it can actually 'easily handle' weight in excess of 1320 lbs. They say things like "Ramp checks are rare and, besides, they check you when you land--after you've used up a lot of weighty fuel."

Don't want to get anyone in trouble, so all responses will treated as hypothetical, not any sort of personal experience or advice.

Thanks.

bshort · Joined: 09 Jul 2010 Posts: 59 Location: Ca

Each of these groups is chasing the dollar. The instructor wants to sell time. The FBO wants to rent the plane. The salesman wants to sell planes and other pilots want more in the air for lower overall costs...etc.

This happens in everyday life in every type of situation. Used car salesmen exist even in aviation.

Long story short...you will be the one on the hook for being over at ramp check or NTSB invest.

saintlfd · Joined: 17 Jul 2009 Posts: 47 Location: ARGYLE, TEXAS

'Follow the money' seems to explain lots of things in all walks of life.

Thanks for the advice.

ibgarrett · Joined: 04 Dec 2008 Posts: 147 Location: Westminster, CO

Ignoring the 1320lb restriction would be in extremely bad practice by anyone and I would think they are taking at best their license into their own hands and at worst their own (and possibly passenger) life into their own hands.

Can it be done? Yup. But picture the conversation you'd have with the FAA and your insurance company if you wound up wrecking the plane or hurting someone based on that decision. You could loose your license and have a plane to pay for because insurance wouldn't cover the damages from this decision.

IMHO this falls into the category of just because someone else is doing it doesn't mean you should, and if you do, know full well what the additional weight is going to cause the aircraft to perform like. Is it going to stall faster, is it going to be nose heavy, tail heavy and what are you going to do to compensate for it.

I can see an instructor suggesting going over the 1320 limit to see what your reaction may be to it, or to use it as a learning experience. A salesperson suggesting it would cause me to question his or her credibility - sort of like a used car sales person suggesting something about a car that would cause my eyebrow to raise in question.

Anyway - that's my $0.02 worth...

FastEddieB · Joined: 07 Jan 2009 Posts: 207 Location: Mineral Bluff, GA

Bad idea all around.

The world will probably not come crashing down around you if you operate at 1,321 lbs. The key word here is "probably". You become a test pilot and set up a slippery slope.

The report linked below was for an aircraft I rented out in S FL. It probably was not being over gross alone that led to two deaths, but it was likely one of the old "links in a chain".

http://www.ntsb.gov/ntsb/brief2.asp?ev_id=20001208X07205&ntsbno=MIA97FA047&akey=1

Here's the doomed plane in better times at N Perry Airport in Hollywood, FL:

Jim Stewart · Joined: 12 Oct 2006 Posts: 259

Every time I have to make a safety-related call in the airplane, I ask myself "Is this something I'd want to have to explain in an NTSB hearing?"

Jim Stewart · Joined: 12 Oct 2006 Posts: 259

Fast Eddie,

Thanks for the link. I don't think weight was the issue, but as they say, sometime the holes in the swiss cheese line up....

Cub flyer · Joined: 10 Sep 2006 Posts: 593

I never understood why the Citabria line only had one gross weight. The airplane is very capable but useful load limited on the GCAA and GCBC.

Seems like they could have a Aerobatic weight and a normal category weight just like a lot of airplanes have a utility category weight and normal category weight.

It would be a lot easier for the FAA to say sport pilots are limited to pilot and one passenger in any airplane that meets the speed limitations of LSA at gross weight and is fixed gear with fixed pitch prop. Keep all the other rules the same.

Instantly thousands of easy to fly, proven, large person capable airplanes are available nation wide to own or rent.

RyanShort1 · Joined: 17 Aug 2010 Posts: 101 Location: San Antonio, TX

I try to NEVER, EVER fly over gross - especially in the Cub, even though I have personally seen it carry quite a bit more. It's annoying when you know that the combined weight of another instructor and student cannot be within limits...
Our Cub's useful load is just shy of 390 lbs. I'm 150 lbs... and with 72 lbs of gas, that only leaves 168 lbs for passengers unless we leave some gas out.

Ryan

Cub flyer · Joined: 10 Sep 2006 Posts: 593

Sounds like the new Sport Pilot legal Aeronca Champ useful load. 370 lbs on the website

What kind of Cub do you have?

Can you get rid of anything not needed? My 46 J-3 has 495 lbs useful. Stock 65hp except for McCauley metal prop and 3200 Scott tailwheel. I have weighed it.

I wonder why the late serial number J-3/PA-11 is 1220 lbs gross on wheels but 1320 lbs gross on floats? Landing gear limitation?

To change from 1185 to 1220 gross on the earlier metal spars is a change in landing gear parts.
Wood spar is stuck at 1185 lbs but a local here has a Wag Aero Cuby with O-290 135 hp, full electric and a lot of Super cub parts. wing tanks, larger tires, extended baggage, etc.

Still the original wood spar with J-3 rib spacing. I looked and the spar is basically the same physical size as the Citabria spar and they are approved for aerobatics at a much higher weight. The rib stitch spacing scares me because he cruises at 100+ and it's spaced for the J-3 122 mph redline.

He is at 1100+ lbs empty and the airplane is 25 years old. But it's an experimental AB and he can do what he wants. There are two extra tubes in the windshield area to connect the fuselage to the forward spar attach fitting.

FastEddieB · Joined: 07 Jan 2009 Posts: 207 Location: Mineral Bluff, GA

Quote: Our Cub's useful load is just shy of 390 lbs. I'm 150 lbs... and with 72 lbs of gas, that only leaves 168 lbs for passengers unless we leave some gas out.

At the bottom of this spreadsheet is a "quick and dirty" calculation of how much fuel I can carry in my Sky Arrow with various passenger weights (I weigh about 190 fully clothed):

Cub flyer · Joined: 10 Sep 2006 Posts: 593

I'm sorry I went back and read the accident report linked above.

I don't think gross weight had anything to do with it. I've seen several crashes of airplanes with the same size bolt in the rear spar. Not one had a failure of the bolt from impact damage. The spar always broke first.

The elongated fittings would be the key. Looking close if it was wear then the bolt had been loose for some time. I have also seen where a loose castle nut wore the cottor pin down to the point it was paper thin. The fit of these bolts is usually good and it's loaded while flying so even without a nut I can't see it falling out. I'm guessing it was probably loose and the spar working back and forth wore a step in the bolt shank. The step was the stress riser causing it to fail.

AN AN-4 bolt is very strong in shear loads. The bolt could also have had corrosion that could not be seen without removing it. Was the airplane ever recovered in it's life where the wings were removed? Was there ever any wingtip damage on that side?

I rebuilt a Citabria once for a guy who owned a garbage truck service. he was bragging to everyone about the aerobatics he was going to do. I took the single right wing strut lower bolt to him one day and said "open your hand" I placed this little bolt in his hand and said "This is what holds your wing on" After that he says he does not even roll out of bed.

Fast Eddie I like the spread sheet. It gives exactly what you can do with what you have. We need more of those.

FastEddieB · Joined: 07 Jan 2009 Posts: 207 Location: Mineral Bluff, GA

Quote: I don't think gross weight had anything to do with it. I've seen several crashes of airplanes with the same size bolt in the rear spar. Not one had a failure of the bolt from impact damage. The spar always broke first.

This will probably remain a mystery.

We had just done an owner-assisted annual. As part of that, the wing root fairings were removed and the wing and strut attachment points inspected. There would have been no reason to disturb any of the attaching hardware, and neither the wings nor the struts had been off the plane in the time we had it.

I had flown the plane a few times since the annual. As part of my preflight, I would shake the wingtip and look for any slackness in the fabric on the top or bottom of the wing. None was apparent.

The three possibilities:

1) Somehow the bolt had completely come loose, involving a missing cotter key

2) The bolt was sheared so cleanly in the accident that there was not deformation of the holes, or,

3) Someone nefariously removed the bolt.

#3 will always haunt me. I owned a business nearby, and I try to imagine who might have wanted me dead - and then by chance killed the wrong persons. The plane was in a T-port with no real security, so anyone could have done it. The report states the facts were forwarded to Broward County homicide, but I don't remember any follow-up.

As far as gross weight having nothing to do with it, one can at least imagine a scenario where the plane, if under gross, might have suffered a deformation short of failure in the same alleged overload situation. Who knows? We all know that aircraft accidents often involve numerous contributing factors, and I think we have to count over gross as one of these factors.

Cub flyer · Joined: 10 Sep 2006 Posts: 593

I wouldn't worry about #3. The wing won't stay on sitting on the ground with the bolt removed.

I'd look into the airplane having struck the wingtip at some point or corrosion The bolts are soft and can displace a bit without breaking. Eventually there might be a crack at the point the bolt joggles. I can't see the bolt breaking from crash stress without pulling the fitting from the wood spar. I've found numerous cracks in the spar butt ends and at the wing attach fitting area but never a problem with the actual metal fitting.

Could the wrong size bolt have been installed at rebuild and ever caught? I've seen it on other airplanes. Not wing spar fitting but other critical parts.

They could have pinned the wing on with a smaller bolt. Then if it was correct length just installed nut and cottor pin.

Wiggling the wingtip might not show anything up like this unless you chock the wheels and wiggle fore and aft. A friend of mine almost got killed in a Beaver. He had wing flutter and got it under control. The airplane was junk afterwards. Worn aft wing attach fitting.

I just don't think overgross was a problem. I think the Scout has the same fittings and is a lot heavier gross weight.

Sad to hear of things like this. It would be good to know an exact cause.

RyanShort1 · Joined: 17 Aug 2010 Posts: 101 Location: San Antonio, TX

Cub flyer wrote: What kind of Cub do you have?

Can you get rid of anything not needed? My 46 J-3 has 495 lbs useful. Stock 65hp except for McCauley metal prop and 3200 Scott tailwheel. I have weighed it.
It's a 65hp stock 1946 Cub. I can't think of ANYTHING you could take off of it to save weight at this point. It doesn't have any electrics, a radio, extra instruments, etc...

Here's the W&B data...

I'd REALLY like to have access to a tailwheel aircraft with a better useful load and a VOR so I could take students all the way to Private Pilot in it.

Ryan