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Overweight take off with a Socata TB20

The maximum take off weight for my non GT Socata TB20 is listed as 1400kg. I am wondering what’s the worst that can happen if I take off with 1 crew and 3 pax, full gas and about 20kg of baggage?

The aircraft is equipped with a full TKS system that should weight about 40kg.

Did any of you take off with an overweight of let’s say 50 to 100kgs? Is it really dangerous, or I only need a longer runway and stay clear of turbulence?

LRIA, Romania

AlexTB20 wrote:

The maximum take off weight for my non GT Socata TB20 is listed as 1400kg. I am wondering what’s the worst that can happen if I take off with 1 crew and 3 pax, full gas and about 20kg of baggage?

The plane can crash and everyone aboard can die.

The W&B is not advisory. If you go outside it you are a test pilot.

EGTK Oxford

AlexTB20 wrote:

I am wondering what’s the worst that can happen if I take off with 1 crew and 3 pax, full gas and about 20kg of baggage?

You can try 1, 2, 3 & bags

GC limits, you are dead as you can’t control it as simple as that
Gym does not help neither but fly it with trim in the corners and see how it feels?

MTOW limits, you will not climb as fast as you want and flight envelope will be constrained, so that performance deterioration is debatable but remember you are insured when it climb at 800fpm not 50fpm at SL and it should break at 6G/250kts not 1.5G/140kts

There is a rule in aerodynamics that once lift = weight, the aircraft is no longer aware of it’s mass, those who design engine, structure and controls completely disagree on this, especially for stability: B737Max is just a B737 overweight

AlexTB20 wrote:

Did any of you take off with an overweight of let’s say 50 to 100kgs? Is it really dangerous

Can you do it? assuming no concern on runway length it simply depend on delta of MTOW vs ROC at SL and the planned altitude, a bit like being able to fly higher

The big unknown is [GC, V, G] limits above max MTOW comes from my extrapolation but looking at design tolerances for a conservative engineer should give some ideas for an aggressive pilot, I will start there?

FYI, the POH limits for new aircraft is eroded by fuel/speed efficient designs while old aircraft tend to be solid as they only have to carry extra fuel

Last Edited by Ibra at 06 Aug 18:26
ESSEX, United Kingdom

It seems to me there are two main engineering issues with an overweight light aircraft, assuming the CG is within limits: the first is structural strength for a given G load, meaning you can break the aircraft more easily, and the second (and more likely to get you) is climb rate. A related issue is that the published airspeeds for best performance will be higher than published, e.g. Vx and Vy, due to higher angle of attack at a given indicated airspeed. Ground handling also tends to vary, especially on tail wheel aircraft, and landing gear isn’t designed for overload.

Obviously people fly aircraft a few percent over gross and get away with it – how many C152s go out on a training mission under gross weight? So why avoid it? First is that many aircraft tend to load in such a way that drives the CG out of the envelope (a BIG deal) when they are over gross. If that’s not the case the biggest motivation for me personally assuming low DA is that the C of A is not in full force and effect when even slightly over gross, meaning your insurance is under the terms of the contract invalid regardless of what may result in a claim. I don’t want the weight situation in the mix after I run off the runway for a different reason and wreck somebody else’s plane.

Last Edited by Silvaire at 06 Aug 19:08

The CG is within limits, only the total weight is about 45kgs above limit.

I often hear stories about Cessna 152 or Cirrus SR22 that take off overweight on a daily basis with no issues.

The TB20 seems stable enough during flight and it’s not underpowered as its smaller sibling TB10, however I also hear horror stories of aircraft crashes at take off caused by WB miscalculations.

I suppose I can try taking off tomorrow with 2 passengers and full tanks first (within limits, just close to the edge of the WB graph), to see if I notice any strange behavior…

Last Edited by AlexTB20 at 06 Aug 18:59
LRIA, Romania

Standard operating procedure for loss adjuster/crash investigator to check the M&B for the flight, also on ramp inspections in certain jurisdictions.

Enstone (EGTN), Oxford (EGTK)

AlexTB20 wrote:

Did any of you take off with an overweight of let’s say 50 to 100kgs? Is it really dangerous, or I only need a longer runway and stay clear of turbulence?

Of course nothing drastic happens if you take off slightly above MTOM. As long as the GC is ok everything that’s happening is that you’re sacrificing your margins. My personal policy is to not knowingly take off above MTOM, but I don’t worry that I get the weights of pax, fuel and luggage a few kilos off.

ESKC (Uppsala/Sundbro), Sweden

AlexTB20 wrote:

I am wondering what’s the worst that can happen if I take off with 1 crew and 3 pax, full gas and about 20kg of baggage?

Crash and burn of course Fuel could be a problem. When it’s used, the CG can wonder aft or fwd depending on where the fuel tanks are. When you start, the CG could be OK. When you land, the CG could be way aft for instance. I don’f know how the fuel affects the CG in a TB20.

“and stay clear of turbulence?”
How can you ensure this?
What if you had to land immediately after t/off, with little fuel burned off?
The touch-down will have to be very gentle, and probably at a higher speed. And if you had to do an off-airfield landing?

Maoraigh
EGPE, United Kingdom

What if you had to land immediately after t/off, with little fuel burned off?

To be fair that is a problem on nearly all bigger planes where the MTOW is above the max landing weight and there are no facilities for dumping fuel. I have been a passenger on a PA46 overweight landing is the key is to touch down smooth and obviously nothing will happen. But not the day for a “smash it down” landing.

As a co pilot before I had my own license when I did not know better to critize the pilots in command I have witnessed a few overweight operations. The most scary part is if the aircraft is power limited or the runway is short. It is a strange feeling if at rotation the plane will just do a wheelie. Also another plane did lift off for a second got back on the main gear accelerated a little more and then lifted off again. Also not funny at all. The take off run gets much longer. Acceleration is worse and you need more lift off speed.

If the plane is not power limited but somehow certification limited it is a lot less scary. Planes like PA46 JetProp will take off without problems even half a ton overweight. But you have to be aware that all the build in margins for an off field landing, stall speed, structure are off. This is especially dangerous if most of the weight is in the fuselage. Weight in the wings at lest does not stress the wing spar fuselage link where most airplanes break in a worst case.
If the CG moves aft and the trim by the autopilot ends up in a unusual position by the autopilot low speed handling can be interesting. Better not get slow on approach.

I did also witness a Beech F33A falling back over on the apron after everybody got in. Also not funny at all. Fortunately I was not on board but the pilot got the engine working and the idle thrust then kept it in balance.

So I suggest to stay within the limits. Often overweight take off results from too much fuel on board. While proper fuel reserves are important it is not worth to transport several hours of excessive fuel reserves at the price of a scary and illegal take off.

www.ing-golze.de
EDAZ
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