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Would you or do you takeoff above MTOM?

The 3.5 kg added (i calculated that with two apps for the SR22 and made a simple test with the GPS, which records the speeds)

Takeoff roll was about 30 feet longer, and i could not see any obvious) difference in climb rate.

@what_next
I appreciate the effort you put into your answer, but i think you exaggerate the matter. My opinion: If 20 lb made any difference at takeoff, how could the ferry planes with +300 lb overweight (more?) ever be operated safely? And those pilots don’t usually have a higher qualification than me.

BTW: i was more interested in the technical aspects and your experience, and less in moral supervision. I am the super careful type, FWIW.

The insurance company will always pay third party damage but they will come after you if they have the slightest chance.

In the UK the insurer won’t come after the named insured.

They can go after anybody else.

So e.g. they can go after you if you are renting. The school’s name would have been on the Policy, not yours. This is rare but possible.

There was another German registered TB20 on jacks there and I was told it had been there for months as the owner and the insurance company were fighting the payment of a gear up landing.

The problem is that most of the time people don’t tell you why their insurance didn’t pay up, or why it took so long. One common reason is connected with what in the UK is called betterment. This means that if e.g. you do a gear up and the engine was at 1900hrs, and (G-reg) the prop was at 5.9 years, they aren’t going to pay for a shock load inspection and a new prop. All they will pay for is parts inside the engine which are found cracked in the opinion of an engineer due to the shock load event and for parts of the prop mechanism (same comment). Of course the owner won’t like this because he was hoping to run “on condition” till the end of his flying career And now he has a plane which is a piece of wreckage unless he spends a load of money on it. Also he won’t get insurance money until he has paid for the engine to go to an OH shop to be opened up. Obviously he is mega p1ssed off about it, but will you hear the true story? I have heard so many proven stories from behind the scenes in GA and I know that when someone’s pride is at risk they rarely reveal what is really behind something. And I am sure other countries have similar rules on betterment otherwise the insurance would be effectively “new for old” which would be an open invitation for somebody needing an overhaul and a new prop to land gear up, which is quite safe if done on a hard runway. Another thing is that the gear may have failed because the plane had not seen a spoonful of grease in the previous 10 years, which is also quite common (rarely causes a gear up however; the pump is about 2000psi output). I reckon that if the insurer finds the plane was manifestly unairworthy, they will dig around a bit before paying out some 30-40k. And again the owner isn’t going to say he operated a piece of wreckage for last X years, and his maintenance company definitely won’t say that

I don’t think there is a single proven case of insurance not paying out purely due to over-MTOW. It would be negligence (the “gross negligence” is a special German legal term) which is covered, and passengers often lie about their weights, especially some who you as a man will be embarrassed to ask

Administrator
Shoreham EGKA, United Kingdom

Airborne_Again wrote:

The best glide speed will increase,

Which on the other hand means that you will fly faster into your unprepared field (= crash with more energy). And for how much weight the Cirrus chute was designed we don’t really know…

EDDS - Stuttgart

Flyer59 wrote:

i was more interested in the technical aspects and your experience, and less in moral supervision.

I didn’t want to sound my answer “moral” in any way. But as a person who instructs flying to ATPL level and who flies for a living, what can I really write on a public forum?

EDDS - Stuttgart

Peter wrote:

Rather than going round and posting personal views does anyone know the % effect of say 1% over MTOW on the takeoff roll and the Vr?

That’s not difficult to estimate. Since lift varies with the square of the speed, Vr would increase by about 0.5%.

If we assume that the engine thrust, F, is constant over the take-off roll (it is not, for propeller aircraft, but we are just making an estimate here), and also assuming that the aircraft actually lifts off at Vr (it does not), then the ground roll distance would be: Vr^2 * m / 2F. A 1% increase in mass, m, would then increase the take-off roll by 2%.

Or in other words, the take-off roll will change as the square of the change in mass.

ESKC (Uppsala/Sundbro), Sweden

assuming that the aircraft actually lifts off at Vr

It won’t if it is heavier…

Administrator
Shoreham EGKA, United Kingdom

@what_next
have figuring out the difference in Vbg for +20 lbs above MTOM. … That’s very theoretical and imply that in case of engine failure you would always fly the right Vbg for your actual weight, wind…

It’s ok to critisize me for those two flights, but, as we say in Germany, “please leave the church in the village” ;-) (do not blow it out of proportion)

By the way: Have you ever broken the crosswind limit of your plane? (Why?)

Last Edited by Flyer59 at 04 Jan 16:18

If Vr is +0.5 percent, then it’s 70.35 knots, not 70.

It did feel fast! :-)

The typical t.o. roll would increase from 300 m to 306 with the 2% rule. My app said 30 feet, so that’s pretty precise.

Last Edited by Flyer59 at 04 Jan 16:23

Flyer59 wrote:

It’s ok to critisize me for those two flights

I have not criticised you in the least, Alexis!

Flyer59 wrote:

By the way: Have you ever broken the crosswind limit of your plane? (Why?)

Luckily I can’t do that because my current plane only has a maximum demonstrated crosswind component. However, our company gives us crosswind limitations. I have not deliberately broken any of those. (One reason being that I cannot be sure if my co-pilots will not report me for it and I still have some years left until retirement…)
But I have accepted “optimistic” wind readings as truth given to us by some ATC staff who know about such limitations and don’t want to be in the pilot’s way.

EDDS - Stuttgart

Peter wrote:

Rather than going round and posting personal views does anyone know the % effect of say 1% over MTOW on the takeoff roll and the Vr?

I think that is the clue here. For any particular aircraft, what limits MTOW may be different things, but I would guess it is strongly connected to stall speed. Experimental aircraft have no set in stone MTOW, but even for them, going outside the limits of the manufacturer put your plane in a situation it was not designed for. You don’t know exactly what llimits the MTOW unless you have designed the plane yourself.

A ferry flight, or any other very long flight, is a different scenario. Normally an aircraft must be able to take off and land at MTOW (or very close, as you obviously use some fuel). For a ferry flight, the intention is to use all the fuel in flight; take off at MTOW+ and landing well below MTOW. I believe more in using your head than sticking to regulations at all cost, but insurance companies most certainly do not agree. For that reason, making it a general rule to take off above MTOW is not using your head in my opinion. Doing it occasionally, and in agreement with the insurance companies for specific flights is.

The elephant is the circulation
ENVA ENOP ENMO, Norway
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