a PBY will carry a two thousand pound over load with no real problem.

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TwinOtterFan
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Big Pistons Forever wrote:
Sun Jun 06, 2021 5:35 pm
You can be inside the envelope at takeoff with full tanks but aft of the aft limit at landing after burning off fuel.
Tomorrow is supposed to be kinda crappy so I may try and do this, but just so I'm not starting off on the wrong page is the basic premise that as the fuel which is close to C of G burns off that portion gets lighter but the aft cargo doesn't change eventually becoming heavier? Or more accurately not lighter?

Without really knowing anything (I'm new and learning and okay with that), and having not done the calculation I'm surprised that you are able to calculate that and it falls within proper flight parameters.


Big Pistons Forever
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TwinOtterFan wrote:
Mon Jun 07, 2021 3:56 am
Big Pistons Forever wrote:
Sun Jun 06, 2021 5:35 pm
You can be inside the envelope at takeoff with full tanks but aft of the aft limit at landing after burning off fuel.
Tomorrow is supposed to be kinda crappy so I may try and do this, but just so I'm not starting off on the wrong page is the basic premise that as the fuel which is close to C of G burns off that portion gets lighter but the aft cargo doesn't change eventually becoming heavier? Or more accurately not lighter?

Without really knowing anything (I'm new and learning and okay with that), and having not done the calculation I'm surprised that you are able to calculate that and it falls within proper flight parameters.
The fuel tanks on the Bonanza are in the leading edges of the wings and therefore ahead of a typical loaded C of G. As fuel is burned the C of G moves aft.
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Liquid_Charlie
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I know things have changed and life is far more complicated today but the fact remains that people were taught to fly for many years, owned and operated their own aircraft, did check rides and flew bonanzas departing with the nose oleo fully extended (as foolish as it gets) without filling out and calculating W&B paperwork. In all those years never completed a weight and balance before a flight. If you understand it and know "why," all of a sudden you have tamed the fire breathing dragon.

One thing that people take for granted is that the aircraft M/T weight is accurate. It isn't always and you are just taking a maintenance engineer's word that the aircraft was weighed accurately. Not always the case and I have seen several aircraft have dramatic weight change after a re-weigh. We are talking on a DC-3 T that weighed over 500 lbs more. That means the aircraft has been flying around at 500 lbs over gross on every max load takeoff for several years but the paper said we were legal. Ironically no change in how the aircraft flew. As I said, this has happened more than once in my career. It was always a nonevent from the flying side. I'm not condoning overloading but the point I'm getting across is it is just math and with that no guarantees it's accurate.

How many flight crews and pilots dick with male, female, child standard weights to make a W&B show legal - has happened thousands of times a day in the past. Is it still going on, I don't know.

How do we beat "practical" back into flight training. Large flight bags should be outlawed :mrgreen:
"black air has no lift - extra fuel has no weight"
TwinOtterFan
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Liquid_Charlie wrote:
Mon Jun 07, 2021 2:47 pm
One thing that people take for granted is that the aircraft M/T weight is accurate. It isn't always and you are just taking a maintenance engineer's word that the aircraft was weighed accurately. Not always the case and I have seen several aircraft have dramatic weight change after a re-weigh. We are talking on a DC-3 T that weighed over 500 lbs more. :mrgreen:
This may be a dumb question, but what causes this? I have actually been wondering this for a while, when I was looking at Champs to purchase I came across a couple of pilots arguing over the useful load on a particular one for sale. Pilot A said you should always have the plane weighed after you purchase it so you have hard numbers, Pilot B (the seller I think) said that he never has his plane weighed because he doesn't want the useful load to change. Clearly knowing it has gained some sort of weight, I just watched them argue but always wondered what is changing the weight that significantly?
David MacRay
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Adding or changing parts.

If the new parts are different from the old parts the weight can change. Sometimes people will add equipment and don’t want to update the empty weight.
said that he never has his plane weighed because he doesn't want the useful load to change.
Other times it gets missed.

A new radio can often weigh less nowadays, so sometimes a change ends up reducing the empty weight.
Squaretail
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I recall one time an AME told me about a plane they reweighed when it was imported was mysteriously 200lbs heavier than it’s listed empty weight. Upon investigation, they found 200lbs of cocaine stashed under some of the belly skin. Turns out a few owners back it was bought at one of those state auctions where they dispose of ill gotten property.

Besides that extremely odd example, planes tend to gain weight incrementally over time. I recall seeing a demonstration of how much of the unusable fuel that can be displaced by water in a Cessna’s fuel tanks, without being able to be drained by the sample point. So if planes accumulate this over time, well water weighs more than avgas or jet-a by a significant margin. Paint also weighs more than one would think, so any touch up work, never mind fibreglass repair also creeps up the weight over time but are generally too small individually to warrant w&b revisions. I can’t remember off hand what the threshold is that requires it. Skin repairs may use larger rivets, fairings bigger screws, upholstery more stitches, different material... all adds up over time.
The details of my life are quite inconsequential...
David MacRay
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I have only ever seen water in a fuel sample once. I went flying with my wife and an instructor out of Maui.

Chuck will be thrilled to know he did not do a weight and balance form.

When I asked where their forms were he said something like, “We don’t need to do that. It’ll be fine.” I figured he is a small fellow and the PIC. Off we went. I won’t lie, I was apprehensive during the takeoff roll. After wheels up we climbed out at a normal rate for 70 knots in a 172, so fair enough it was fine that day and a great flight.
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Liquid_Charlie
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While it's obvious they were overloaded there has to be more to this than that. How often had he carried passengers in the past and at 134kg we are talking NFL footballer here. I doubt anyone that was 5'5" and weighing that much could struggle into that aircraft.

This is an experienced pilot and while putting "andre the giant" in the right seat was the start of it all there had to be another factor at play.

I have no idea how an aircraft like this flies but he should and obviously didn't have a concern about the the situation. I have a tendency to go with he might of not been at the controls and let it go too far (which would be exaggerated by the aircraft weight) . Why would they get so slow, maybe the "big man" obstructed the controls.

I don't like reports or articles like this because they "cherry pick" data. The fact that the aircraft was overweight does not generate a large fly swatter that smites you from the sky.
"black air has no lift - extra fuel has no weight"
David MacRay
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Liquid_Charlie wrote:…I don't like reports or articles like this because they "cherry pick" data. The fact that the aircraft was overweight does not generate a large fly swatter that smites you from the sky.
That’s reasonable.

I don’t disagree but I believe it’s relevant, especially when people are talking about how heavy they “can safety overload a Catalina”, in a thread I foolishly thought we might be able to discuss reading a paper chart to navigation in.

Maybe you can fly over weight.

I say, as long as you have enough fuel, you can fly even safer underweight.
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