Overloading Max Gross

[Mike I]

If you ever fly out of republic you'll know what I mean. It's worse than JFK. Some commercial rated pilots would not even go to KFRG. 2 weeks ago I was inbound for full stop - took me 30 minutes to actually touch the ground. 2 go arounds and twice number 8 on final! No kidding. (Go arounds due to idiots not getting off the runway in time) so when I fly to other airports in the vicinity, my first thought is "where is everyone", almost like unless there are 15 planes in the pattern I have a feeling that something is not right and its not my home airport, especially on VFR weekends. LOL

I had that experience there a few weeks back. Coming back in to FRG from up north around sunset, and I couldn't get in a word with the tower announcing I was inbound, despite starting calls 12-14nm out. Finally got a call in about 7nm out, with no acknowledgement. At about 6nm, tower asks "who's the aircraft 5 north of the field, 2200'?" "That's me, N#####". Tower: "Do you realize you've entered Class Delta without communicating with me?" Me: "I'm showing I'm 1/2mi north of the Delta, been trying to reach you for 5 minutes"... Tower: "Turn north, hold at the shoreline, call you back in 10 minutes" (in a gruff manner).

Tower finally calls, I'm #6 to land. Puts me behind a ridiculously slow aircraft doing probably 65kts while still 5mi out or so, and I can't slow down quick enough. I ask for a 360 for spacing, granted. Now on short final, tower orders me to go-around due to jet traffic behind me. Very tempted to reply Unable but I comply. I'm vectored back around, #6 to land again. That nonsense probably cost me $50+, paying by Hobbes on rental. Pretty frustrating. That's only happened a few times to me at FRG, and isn't the norm.

 

[Skylane81E]

The fact that an airplane has more than 200HP doesn't make it any better performer when loaded over max gross than an airplane with less then or equal to 200HP also loaded over max gross. And it certainly doesn't make the aircraft's structure any more able to withstand a max limit vertical gust.

The only real affect I see is that the bigger the plane the less overloaded you are as a percentage of gross.

 

[N521MA]

I had that experience there a few weeks back. Coming back in to FRG from up north around sunset, and I couldn't get in a word with the tower announcing I was inbound, despite starting calls 12-14nm out. Finally got a call in about 7nm out, with no acknowledgement. At about 6nm, tower asks "who's the aircraft 5 north of the field, 2200'?" "That's me, N#####". Tower: "Do you realize you've entered Class Delta without communicating with me?" Me: "I'm showing I'm 1/2mi north of the Delta, been trying to reach you for 5 minutes"... Tower: "Turn north, hold at the shoreline, call you back in 10 minutes" (in a gruff manner).

Tower finally calls, I'm #6 to land. Puts me behind a ridiculously slow aircraft doing probably 65kts while still 5mi out or so, and I can't slow down quick enough. I ask for a 360 for spacing, granted. Now on short final, tower orders me to go-around due to jet traffic behind me. Very tempted to reply Unable but I comply. I'm vectored back around, #6 to land again. That nonsense probably cost me $50+, paying by Hobbes on rental. Pretty frustrating. That's only happened a few times to me at FRG, and isn't the norm.

Thats my airport )

 

[ja_user]

An Archer to the tabs, still is carrying a lot of full. The tabs are 17 (or is it 18) Gallons each right? So 3.4 Hrs of fuell if both are at the tabs and 10GPH. Drop 8 Gallon out of one tank and make a stop, or lose some luggage. It really isn't that hard to figure out..

 

[poadeleted20]

Look at 91.323 are you telling me that by magic an aircraft can carry 15% more in Alaska if operated by the right entity? What? I guess the laws of physics are different up there and the aircraft knows what name is on the pilot's paycheck.

The LoA allowing such operations requires professional pilots under a commercial operating certificate (whom the FAA does assume to be more competent than the average Joe) and specific restrictions on the operation. IOW, your example simply isn't relevant to this situation. By analogy, one might say that since the FAA lets specially certified airline pilots with certain equipment fly Cat II approaches down to 100 RA with 1/4 mile vis, anyone with that equipment can do the same safely. Ain't so.

 

[bbchien]

An Archer to the tabs, still is carrying a lot of full. The tabs are 17 (or is it 18) Gallons each right? So 3.4 Hrs of fuell if both are at the tabs and 10GPH. Drop 8 Gallon out of one tank and make a stop, or lose some luggage. It really isn't that hard to figure out..

It sure is when there is no apparent penalty the first time, so there will be a second time.... and a third and eventually a newspaper article....

 

[redtail]

I had that experience there a few weeks back. Coming back in to FRG from up north around sunset, and I couldn't get in a word with the tower announcing I was inbound, despite starting calls 12-14nm out. Finally got a call in about 7nm out, with no acknowledgement. At about 6nm, tower asks "who's the aircraft 5 north of the field, 2200'?" "That's me, N#####". Tower: "Do you realize you've entered Class Delta without communicating with me?" Me: "I'm showing I'm 1/2mi north of the Delta, been trying to reach you for 5 minutes"... Tower: "Turn north, hold at the shoreline, call you back in 10 minutes" (in a gruff manner).

Tower finally calls, I'm #6 to land. Puts me behind a ridiculously slow aircraft doing probably 65kts while still 5mi out or so, and I can't slow down quick enough. I ask for a 360 for spacing, granted. Now on short final, tower orders me to go-around due to jet traffic behind me. Very tempted to reply Unable but I comply. I'm vectored back around, #6 to land again. That nonsense probably cost me $50+, paying by Hobbes on rental. Pretty frustrating. That's only happened a few times to me at FRG, and isn't the norm.

I wonder if this was the female controller that seems to have a snarky attitude a lot.

 

[gismo]

There is no question whether I will be within limits of max gross by the time I land, as will burn roughly 150 pounds of fuel, which in this case put me 100 below max gross. But taking off with potential 50 pounds over.

Plane PA 28 181 - plenty of power to pull.

I'd still say no-go if you're convinced you'll be over MGW on takeoff. If the runway was long, the DA low, and no chance for moderate or worse turbulence there's probably no real safety issue beyond the "slippery slope" stuff but it just seems like a really good idea to always operate within the approved envelope unless doing so threatens your life. At the very least, I suspect this could invalidate your insurance if they could prove you knew you were overgross and had an accident on departure.

Given your situation it sounds to me like you either need lighter friends or ones that can get by with less stuff. A more capable airplane would be another option albeit a potentially expensive one.

 

[Skylane81E]

Shouldn't invalidate any insurance, it is in place to cover your screw ups.

Might affect insuring the next plane though

 

[onwards]

The fact that an airplane has more than 200HP doesn't make it any better performer when loaded over max gross than an airplane with less then or equal to 200HP also loaded over max gross. And it certainly doesn't make the aircraft's structure any more able to withstand a max limit vertical gust.

50lbs for a 1800lb max gross is a lot more than 50 lbs over for a 3100lb max gross plane.

But I agree with the second observation, which is why I will only do this on a nice day.

 

[poadeleted20]

BTW, as I learned in my ME courses back at the University of Michigan, you can load a structure beyond its intended limit without having it fail the first time. Maybe the second, too, and maybe the third or beyond. But every time you do that, it takes a little bit out of the structure's strength/fatigue life limit, and eventually, it will fail with no more than the intended load on it and/or before its expected fatigue life limit. That's why even though you may get away with overloading your plane just this once, you're setting yourself (or someone else) up for eventual disaster.

 

[MAKG1]

50lbs for a 1800lb max gross is a lot more than 50 lbs over for a 3100lb max gross plane.

NO. It is NOT.

It's about excess power for the climb. For that, you subtract what you need to cruise at liftoff speed. Which is not easily guessed. Did you know a C152 loaded to max can outclimb a C172 loaded to max? Which of these do you think will be better at 50 lb over? Don't guess.

Sometimes the margins are bigger, but if you're going to bet your life on that, you're eventually going to lose the bet.

 

[poadeleted20]

50lbs for a 1800lb max gross is a lot more than 50 lbs over for a 3100lb max gross plane.

I agree that a 3% overload is worse than a 1.5% overload, but the fact that an airplane has more or less than 200HP doesn't change the situation.

But I agree with the second observation, which is why I will only do this on a nice day.

Good idea -- makes it easier to find the wreckage.

 

[bobmrg]

If you're overweight but within CG (and keep in mind those limits get narrower the heavier you are), you'll run into several potential issues:

1) Increased stall speed. In fact, most V-speeds at the low end (NOT Vno or Vne, which will decrease) will be increased by the square root of the ratio of the actual weight to the max gross weight.

2) Longer takeoff roll. Plenty of YouTube videos of overloaded planes going off the end of the runway and crashing on takeoff. The longer takeoff roll is due to the lower acceleration (increased weight, but not increased power) as well as the need to accelerate to a slightly higher speed (see #1).

3) Decreased climb rate. This will be more severe than you'd think - Climb is a function of excess horsepower. Even though you have 180 horsepower, loading to 5% over gross will cause a MUCH more than 5% reduction in climb rate. That's because it takes the majority of your engine power just to stay in the air - So, of your 180hp maybe only 40 of it is excess horsepower available for climb at gross, and that'll get eaten up quickly. This may not affect you too much in winter temps in the northeast, but if you get in the habit of doing it, you may get bitten in the summer.

4) Inability to climb with full flaps - That's the reason MGW is where it is on some airplanes. Could make for an impossible go-around.

5) Structural integrity. Some people say it's OK to go over gross because the plane is engineered for 150% of the design load factor. However, the reason for that extra 50% is so after getting bounced around in turbulence, hard landings, and even potential weaknesses in the design that aren't noticed right away, that you should hopefully still stay in one piece. Do NOT throw that margin away! (I had a very interesting conversation with a Cessna test pilot about this recently.)

The biggest problem is that if you think it's OK to go over gross by 25 pounds today, tomorrow it'll be 50, etc... It's a slippery slope, and you're a test pilot the whole time. Don't fall for the illusion that if it works this time, it'll work next time, because it's dependent on a lot of conditions. The plane has been tested for many conditions to come up with its W&B, performance charts, and limitations. It has not been tested outside those limits, and if you run into one too many conditions that haven't been designed and tested for, you're a smoking crater.

Choose wisely.

Add to #2 increased rolling friction due to a larger main gear footprint.

Bob Gardner

 

[gismo]

Shouldn't invalidate any insurance, it is in place to cover your screw ups.

Might affect insuring the next plane though

If the screw up was deliberate (e.g. taking off knowing you were over gross) it can indeed invalidate although I would expect that in most jurisdictions there would need to be some casual relationship between the overweight condition and the accident (e.g. clipped trees on takeoff vs lost control while landing after burning off the excess weight). If it was "accidental" (e.g. you believed the optimistic personal weights or miscalculated) the insurance coverage should be intact.

 

[gismo]

I calculated the weight and balance for a recent flight for a weekend at hilton head. I told my passengers to please limit their bags for the weekend for 20 lbs.

My girlfriend shows up with a bag that weighed at least 35lbs. For a weekend...


I told her she had to re-pack, and that's what she did. Now, based on the actual weights of the other bags, we had room for a 35lb bag. I didn't mention this. Principles.

Hope she does not see this.

On family trips, my daughter (20 years old) is the worst offender WRT bringing more stuff than she needs when we must pack light and I run a close second. Fortunately my wife is just the opposite, she can go on a two week trip with less than 20 lbs of baggage if she's not bringing stuff for someone else.

 

[Alexb2000]

The LoA allowing such operations requires professional pilots under a commercial operating certificate (whom the FAA does assume to be more competent than the average Joe) and specific restrictions on the operation. IOW, your example simply isn't relevant to this situation. By analogy, one might say that since the FAA lets specially certified airline pilots with certain equipment fly Cat II approaches down to 100 RA with 1/4 mile vis, anyone with that equipment can do the same safely. Ain't so.

The rule does not specify equipment, experience, or any other special requirement. You could have a 250 hour comm. pilot flying a very basic aircraft over gross with no modifications or special inspections. How is that not relevant to the conversation? Further from your other post you suggested that flying over gross would always eventually result in a failure, why would a structural failure care what state you're in or who you are flying for?

That makes no sense to me.

 

[Skylane81E]

If the screw up was deliberate (e.g. taking off knowing you were over gross) it can indeed invalidate although I would expect that in most jurisdictions there would need to be some casual relationship between the overweight condition and the accident (e.g. clipped trees on takeoff vs lost control while landing after burning off the excess weight). If it was "accidental" (e.g. you believed the optimistic personal weights or miscalculated) the insurance coverage should be intact.

You have crappy insurance then, if I'm in annual, have a BFR and a medical I'm covered

 

[gismo]

What if you are at tabs and less fuel is not an option. By the time you taxi out (about 15 mins Very busy airport), climb and 15 minutes into flight - most likely I already will be at limit. Question is really that first 15 minutes and obvious take off.....

JOOC, what does "fuel at the tabs" have to do with this? Is that the minimum fuel required for takeoff? Also, FWIW, the fuel consumed prior to takeoff can legally be deducted from the takeoff weight (within limits in the POH).

If 15 minutes of flight brings the weight into the published envelope, you just need to plan on landing 15 minutes sooner. You might even be able to fly the same distance with identical reserves by going slower and therefore with higher mpg so no extra stop would be needed.

 

[Dave Krall CFII]

Would you please amplify about the conversation with the Cessna test pilot?

If you're overweight but within CG (and keep in mind those limits get narrower the heavier you are), you'll run into several potential issues:

1) Increased stall speed. In fact, most V-speeds at the low end (NOT Vno or Vne, which will decrease) will be increased by the square root of the ratio of the actual weight to the max gross weight.

2) Longer takeoff roll. Plenty of YouTube videos of overloaded planes going off the end of the runway and crashing on takeoff. The longer takeoff roll is due to the lower acceleration (increased weight, but not increased power) as well as the need to accelerate to a slightly higher speed (see #1).

3) Decreased climb rate. This will be more severe than you'd think - Climb is a function of excess horsepower. Even though you have 180 horsepower, loading to 5% over gross will cause a MUCH more than 5% reduction in climb rate. That's because it takes the majority of your engine power just to stay in the air - So, of your 180hp maybe only 40 of it is excess horsepower available for climb at gross, and that'll get eaten up quickly. This may not affect you too much in winter temps in the northeast, but if you get in the habit of doing it, you may get bitten in the summer.

4) Inability to climb with full flaps - That's the reason MGW is where it is on some airplanes. Could make for an impossible go-around.

5) Structural integrity. Some people say it's OK to go over gross because the plane is engineered for 150% of the design load factor. However, the reason for that extra 50% is so after getting bounced around in turbulence, hard landings, and even potential weaknesses in the design that aren't noticed right away, that you should hopefully still stay in one piece. Do NOT throw that margin away! (I had a very interesting conversation with a Cessna test pilot about this recently.)

The biggest problem is that if you think it's OK to go over gross by 25 pounds today, tomorrow it'll be 50, etc... It's a slippery slope, and you're a test pilot the whole time. Don't fall for the illusion that if it works this time, it'll work next time, because it's dependent on a lot of conditions. The plane has been tested for many conditions to come up with its W&B, performance charts, and limitations. It has not been tested outside those limits, and if you run into one too many conditions that haven't been designed and tested for, you're a smoking crater.

Choose wisely.

 

[flyingcheesehead]

Would you please amplify about the conversation with the Cessna test pilot?

Just made me realize that there isn't really as much margin as you'd think there is... Lots more variables than we can possibly imagine. Add them all up, and hope that your 50% isn't eaten up yet. No need to make the Grim Reaper's job easy.

 

[gismo]

Picking a few nits in the name of accuracy:

3) Decreased climb rate. This will be more severe than you'd think - Climb is a function of excess horsepower. Even though you have 180 horsepower, loading to 5% over gross will cause a MUCH more than 5% reduction in climb rate. That's because it takes the majority of your engine power just to stay in the air - So, of your 180hp maybe only 40 of it is excess horsepower available for climb at gross, and that'll get eaten up quickly. This may not affect you too much in winter temps in the northeast, but if you get in the habit of doing it, you may get bitten in the summer.

Climb rate gets hit threefold. First as you point out the power required to overcome induced drag at Vy is higher reducing (at Vy induced drag is proportional to lift and weight), second because Vy is higher the parasite drag will be greater both of which means more power is required to provide enough lift to maintain altitude at Vy leaving (a lot) less for climbing. And third, that reduced HP is raising more weight so the climb rate is even less than the reduction in excess HP would indicate.

4) Inability to climb with full flaps - That's the reason MGW is where it is on some airplanes. Could make for an impossible go-around.

One might argue this would only be a concern if the airplane had to land immediately after takeoff for some reason and then a go-around became necessary. And if the runway was long enough the issue could be mitigated by making a reduced or no-flap landing.

5) Structural integrity. Some people say it's OK to go over gross because the plane is engineered for 150% of the design load factor. However, the reason for that extra 50% is so after getting bounced around in turbulence, hard landings, and even potential weaknesses in the design that aren't noticed right away, that you should hopefully still stay in one piece. Do NOT throw that margin away! (I had a very interesting conversation with a Cessna test pilot about this recently.)

I think I've made this point here before but there is no "extra 50%" design margin, at least it's not required by the certification regs. The 150% you speak of is only regarding catastrophic structural failure (e.g. the wing falls off). Any load beyond the design limit (more than 3.8g at MGW) can produce permanent damage to the airplane. The two limits (100% and 150%) are the yield limit and the ultimate limit respectively. Now it is true that many if not most airplanes designed before computerized FEA was practical (pretty much every piston airplane flying today) did include extra margins to mitigate the lack of detailed accuracy of the stresses involved but even so those same inaccuracies could mean there's really no margin at all in some areas of the structure.

 

[Tony_Scarpelli]

My Cherokee 150hp took off GW and climb at 650' per minute. My Comanche climbs out at 1300' per minute. Seems to me if I were to take off a bit over weight on the Comanche it would be better.

 

[wabower]

If you find that a completed flight was conducted while over max gross due to an error in one of the published limitations do you immediately report to the FSDO and turn yourself in?

QUOTE=Ron Levy;1101766]BTW, as I learned in my ME courses back at the University of Michigan, you can load a structure beyond its intended limit without having it fail the first time. Maybe the second, too, and maybe the third or beyond. But every time you do that, it takes a little bit out of the structure's strength/fatigue life limit, and eventually, it will fail with no more than the intended load on it and/or before its expected fatigue life limit. That's why even though you may get away with overloading your plane just this once, you're setting yourself (or someone else) up for eventual disaster.[/QUOTE]

 

[tmyers]

Absolutely, then you have to tell them where Jimmy Hoffa is buried.

Sad thing is that most probably don't know who Jimmy Hoffa is.

 

[gismo]

You have crappy insurance then, if I'm in annual, have a BFR and a medical I'm covered

I'd be willing to bet insurance premiums that your policy limits coverage for a "deliberate act" contrary to policy requirements or something similar in meaning. Whether or not that includes deliberately taking off over MGW I can't say without reading your policy.

 

[Tony_Scarpelli]

I'd be willing to bet insurance premiums that your policy limits coverage for a "deliberate act" contrary to policy requirements or something similar in meaning. Whether or not that includes deliberately taking off over MGW I can't say without reading your policy.

Insurance is mostly an illusion possibly a fraud.

save your money and put it into your own savings.

 

[Geico266]

I'll bet this pilot thought he could make it.

http://www.youtube.com/watch?v=ffxh7f6tr_k&feature=youtube_gdata_player

Pretty sure this one thought he was gonna take off too.

http://www.youtube.com/watch?v=y4Zr_rYUjro&feature=youtube_gdata_player

This guy made it, barely......

http://www.youtube.com/watch?v=i9DFUqbdH_0&feature=youtube_gdata_player

Or who can forget the Beaver not taking off into the wind to impress his friend video taping the crash.... bet the pilot thought he was gonna make it.

http://www.youtube.com/watch?v=YVwlodvWh7w&feature=youtube_gdata_player

 

[Geico266]

I am we'll aware what the W/B says and always comply within limits, however I have faced a situation where I had to say "we would not be able to go" and wanted to hear your HONEST opinion, not what the book says.....

You plan a flight with your friends to go somewhere, you asked everyone for their weight and baggage, night before you do the W/B and everything is almost at the limit but well balanced and within manufacture's limits.

Next morning all show up the field, you look at the winter jackets, and the guy in the middle definitely lied about his weight. Again, you harass everyone for their exact weight and do the W/B and realize you are over the limit by roughly 25-50lbs (since you don't carry scales in your plane, that is your best educated guesstimate).

You are already at minimum fuel required plus reserves, conditions are CAVU, NE winter temps, basically conditions are almost set for best performance and CG is well balanced. Only issue is that you somewhere (per your guesstimate) over max gross by 25-50lbs

Do you still go or cancel your flight?

Go for it.

 

[wabower]

If your policy contains such language I'd be interested in reading an exerpt.

I'd be willing to bet insurance premiums that your policy limits coverage for a "deliberate act" contrary to policy requirements or something similar in meaning. Whether or not that includes deliberately taking off over MGW I can't say without reading your policy.

 

[wabower]

YGBSM. Full hull and liability coverage for less than 2% of FMV isn't worth the money in hail country?

Insurance is mostly an illusion possibly a fraud.

save your money and put it into your own savings.

 

[cowman]

Here's the thing...

If you start tracking your own weight you'll quickly realize that it will fluctuate as much as 5lbs/day from all the water/food in your system.

Also, try weighing naked, then with your usual clothes on, then throw your winter gear on. Yikes now you're 10-15lbs heavier. I imagine many people will give you their best naked weight. So you've got potentially 40-60lbs of underestimate to begin with even with everyone being basically honest. Then you think you're 25-50lbs over... which might be as much as 110lbs over. About the weight of a really small woman. Would you fly the airplane with all these passengers + a 110lb woman?

Alternatively.... have a bathroom scale handy next time and weigh everyone with clothes on and know. If you're 25 over make everyone go to the bathroom and ditch extra stuff until you make it.

 

[bbchien]

I think the real problem is where do you stop? 3% over? 5% over? 6% over....just because you can (or think you can) does NOT mean you should.

We operated one aircraft on the "lockheed" tables"-35% over civil gross. But the stuff the chiefs had to do every time we landed would make your head spin. All the checklists were different.

So where does it stop?

 

[azure]

Insurance is mostly an illusion possibly a fraud.

If the $10K + that my insurance saved me at my first annual is an illusion, then I'll take it over reality any day.

Besides, carrying hull insurance is a condition of my hangar lease.

"May you find your way as pleasant."

 

[poadeleted20]

The rule does not specify equipment, experience, or any other special requirement. You could have a 250 hour comm. pilot flying a very basic aircraft over gross with no modifications or special inspections.

No, you couldn't. You can't be a 135 PIC with 250 hours TT.

How is that not relevant to the conversation? Further from your other post you suggested that flying over gross would always eventually result in a failure, why would a structural failure care what state you're in or who you are flying for?

Nobody said it did.

That makes no sense to me.

I gather that.

 

[JasonM]

How much weight does rain water add to a plane? I'm not trying to justify anything here, it just popped into my head when reading this. Has to be something semi-substantial right? Do you guys figure that weight in when flying in the rain? btw, i'm just a student, and this post got me thinking.

 

[Inverted]

Planes that have excess power can handle being loaded heavier, that should be immediately obvious. It does not mean the airplane will handle the same, or guaranteed to meet any perimeter within the POH. The BE99 can easily maintain 100FPM climb on one engine at max gross, above 10k. So 2 engines, over gross will be a non event. Even 500 lbs. The problem is when you load or G the airplane. Normal, utility, transport etc categories no longer apply with regard to the design load limits of the airplane. That is when you will really start fatiguing metal...

 

[Aeric]

In this string of postings I see the word "if" and "hope" a lot. Not the words I would ever use to justify taking off knowingly even one pound over gross. The numbers are there for a reason. Sure, you may be able to take off over-gross, but if there is an incident for whatever reason and you survive it, there will be lots of splainin' to do.
Just follow the rules...

 

[Inverted]

How much weight does rain water add to a plane? I'm not trying to justify anything here, it just popped into my head when reading this. Has to be something semi-substantial right? Do you guys figure that weight in when flying in the rain? btw, i'm just a student, and this post got me thinking.

Ice can add hundreds of pounds to an airplane. In theory, it can never really accumulate faster to make you hundreds of pounds over gross though.

Just about only 2 ways to add significant amounts of weight to an airplane. One is in-flight refueling, the other is ice accumulation.

 

[wabower]

The 200 is operated by the military at 10% greater weight than the civilian model that comes off the same production line.

Planes that have excess power can handle being loaded heavier, that should be immediately obvious. It does not mean the airplane will handle the same, or guaranteed to meet any perimeter within the POH. The BE99 can easily maintain 100FPM climb on one engine at max gross, above 10k. So 2 engines, over gross will be a non event. Even 500 lbs. The problem is when you load or G the airplane. Normal, utility, transport etc categories no longer apply with regard to the design load limits of the airplane. That is when you will really start fatiguing metal...