Primarily for general aviation discussion, but other aviation topics are also welcome.
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By kanga
#1839167
When I was in a 2-aircraft group, at one stage it was a Robin HR200 and a Robin ATL ('Avion tres legere' :) ). I loved the latter, but it was exchanged for a TB9 partly because our less 'lissome' members did their sums and worked out that with themselves and an adult male passenger (or the slightly 'well-built' tame FI we usually used for checkouts and biennials) it would be scarcely legal to try to take off with any fuel on board :roll: I was fine with another adult and full tanks, though: both performance and 'feel'.

[The other reason for the swap was that some members wanted a 4-seater, I was unconcerned, and took 3 others in the TB9 only once, one a child. I can't say it was 'sprightly' on that sortie]

Anecdote (longish :oops: ) from charter airline days in '60s:

I had paid for my PPL by working university long vacations for holiday airlines. By working all hours and not having any time free to spend my wages I was able to save a respectable amount to blow on some intensive flying at the end of the summer.

One summer I was at Prestwick, mostly doing a mixture of transatlantic 'Affinity Group' charters with B707-320Cs, and Mediterranean 'inclusive tours' with Britannias. One of the Affinity Group rules was that we could not charge for excess baggage (since the group had chartered the whole aircraft), only offload baggage. With mixed family loads to New York or Toronto the MTOW was usually no problem. However, we once had a group from a 'Scottish Golfing Society' from California, all adult US males (far from slim :roll: ), flying back to San Francisco after 2 weeks touring Scottish golf courses. They wanted to check in large heavy suitcases, the bags of clubs they'd brought with them, and in many cases more clubs they'd bought while in Scotland, and another (new, sturdy) suitcase full of souvenirs .. It was for a mid-morning take-off non-stop to SFO, warm day. It was one of my jobs to do the W&B, including bag and passenger distribution and maximum permissible fuel load, by hand using chinagraphs on a complicated template with sliding and rotating transparent overlays. I showed my sums to the Captain .. He decided it would be very bad customer relations to require passengers to abandon their luggage, to be airfreighted back at their extra individual expense. He worked out that if we assumed standardised 'adult male' weights (probably an underestimate given their typical girths) and a 'generous' taxi fuel burn to the holding point, and filing for Bangor Maine initially, hoping by careful fuel management to have enough fuel remaining on reaching Newfoundland to refile progressively further West in flight .. he might be both legal on paper on takeoff and make SFO non-stop. He signed off the W&B chart. As a further part of my job I went through to the airside lounge to make a Tannoy announcement to our passengers to explain that 'because of forecast winds' it might be necessary to make an intermediate refuelling stop 'somewhere in the US'. I could then see that many of them had by then bought 1-2 large bottles of Scotch in the duty-free. The aircraft was not only going to be heavier, the cabin was going to be full of flammable liquid if it crashed on take-off :? .... Anyway, that dispatch was my last duty that (extended night) shift, and I set off walking to my digs in Monkton (North of the airport) along the coast road which passed under the 30 climb-out. Our aircraft rotated VERY late, passed over the fence (and my head!) VERY low, climbed VERY slowly, and even seemed to roll slightly left to avoid the nearest high ground on Arran; but (as we checked) had made SFO nonstop, with presumably happy but oblivious passengers, likely to recharter us the following year.
Last edited by kanga on Fri Apr 09, 2021 10:57 am, edited 1 time in total.
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By Miscellaneous
#1839171
A4 Pacific wrote:I imagine it could also invalidate your insurance?

That's an example of what I mean, it's totally irrelevant to Steve's question. He acknowledges the MTOW, but is curious about how much beyond it the aeroplane could be and still fly.

I've pondered the same with the VNE safety factor, that doesn't mean I have any desire to test any theory.
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By flyingearly
#1839173
Miscellaneous wrote:
A4 Pacific wrote:I imagine it could also invalidate your insurance?

That's an example of what I mean, it's totally irrelevant to Steve's question. He acknowledges the MTOW, but is curious about how much beyond it the aeroplane could be and still fly.

I've pondered the same with the VNE safety factor, that doesn't mean I have any desire to test any theory.


I'm sure that this exactly conversation/question came up a couple of years ago on here. The 'conclusion' (though not sure how robust it was, or informed!) was that being overweight would only invalidate the insurance if the fact you were overweight contributed to the accident.

E.g. an overweight aircraft involved in an accident on its own (because of engine failure, say), would not afford the insurer the opportunity to refuse to pay out, unless the quantum of damage was affected by the excess weight.

This, of course, doesn't make it right.
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By SteveX
#1839174
MichaelP wrote:The Flyer video chat last night had an item on the new production Luscombe 8.

One day at Biggin Hill a student came in and told his examiner that they would be 40lbs over weight. (Cessna 152). The examiner told him it was normal and they went flying.
In Canada there were no end of times we syphoned fuel out of Cessna 152 tanks to bring them within weight limits.
Then these students get their commercial jobs, and are pressured to fly overweight...

In Thailand the Cessna 152 was regularly flown at 150lbs over weight! The particular ‘instructor’ (he had no instructor rating anywhere) was big, and his Norwegian student was big. This ‘instructor’ took three Dutch people flying (Dutch size) with full tanks, and full flaps, in a Cessna 172F for a short hop to a crash.
.


What I was seeking details on was indeed along the lines of the above. Ignoring insurance, runway length and was wondering when say a 152 has a climb rate of eg 500ish ft/m rather than 1000. So it flies ok, handles ok and lands ok (though it would be within limits on landing obviously. All assuming balance stays within fictitious lines drawn on extending the graph up to a point say 50kgs over MTOW.

I think you mean 172 above Michael when you say 150lbs over? As for a 152 my own pure guess is a 152 does not suffer abnormally with up to 30ish kgs over. That is on a +20c day at sea level. In fact a DA of 2000ft would probably be ok and result in a climb rate of 500 or more.

I don't care a hoot about insurance where owning your aircraft if it resulted in a crash then it is one owns tough luck.
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By kanga
#1839178
SteveX wrote:..

I don't care a hoot about insurance where owning your aircraft if it resulted in a crash then it is one owns tough luck.


.. not when one considers the contingent possibilities of Third Party damages ? :roll:
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By SteveX
#1839183
Very true. I was thinking more of flights where there was a clear climb out eg. fields only off the end of a strip. Being stupidly overweight climbing out over houses could indeed bring in the liability bit.
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By MichaelP
FLYER Club Member  FLYER Club Member
#1839194
I think you mean 172 above Michael when you say 150lbs over?


Nope, I mean Cessna 152 at 150lbs over gross, I’m not kidding.
At +38C and just under 1,000 feet amsl, runway length 900 metres, hard laterite, the Cessna cleared the trees, and then the HT wires south of the field.

This pilot regularly flew well over gross.
He came a cropper in the Cessna 172F when he tried to take off, well over loaded, and with forty degrees flaps selected... He was too lazy to do his pretakeoff checks.
He and I had arguments, but I was powerless as he was in a senior position to me.

Many people like to always takeoff with full tanks.
This is sometimes a bad idea.
You must know how much fuel you have.
You must learn how to lean the mixture to get the book fuel consumption figures even below 3,000 feet.
You must be very careful balancing the fuel load against the honest weights of the POB, and their bags.

So we takeoff in a Cessna 152 at fifty pounds over gross, and all is well with the World.
We’re flying north with a strong wind from the west, and we’re on the east side of the Pennines. There’s a fair amount of wave.
In the downdraught we’re having to apply more power to maintain our planned for TAS, our range is affected...
Ideally we learn to read the clouds and fly in the updraught.

We find in cool air we can takeoff overgross from our strip.
Then one day its warm, with a light breeze over the trees to the side of the strip...
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By MichaelP
FLYER Club Member  FLYER Club Member
#1839205
Image
Image

In the summer of 2019 I was caught out twice.
At Black Diamond I was to fly with a friend the next morning... I did the numbers, and the Taifun would be off around halfway down the strip at gross weight according to the Flight Manual.
I put limited fuel in the tanks to be below gross weight.
On takeoff the aeroplane was rotated too early twice, and we went beyond the go/no go point before the pilot in the left seat handed it over to me for the crash...
I lowered the nose and the Taifun became airborne and in a shallow climb we did not hit anything....
The moral of the story is that when you need the best performance you need to fly accurately.
Overload your aeroplane, fly accurately.

Get off the grass!
I took the Taifun solo to the nearby aerodrome with a hard runway. There two up, we should easily get off.
Nope.
The Taifun is like a dh Comet airliner, or a Vampire. Rotate too much, and the drag wins vs the VW engine, and you’re going off the end of the runway.
Downhill there were houses... Not tempting.
Uphill there was an open field. We went uphill.
Over rotate up and down, and “I have control!” Again I lowered the nose and she flew... In ground effect above the gently rising ground.
It would be easy to throttle back and settle into the crop... The wires at the far end of the field were a hazard, but she was performing sort of...
I wound the wheels up, did a shallow right turn, picking up energy, and easily climbed above the other wires at the end of the field in that direction.

Later happy at 9,500 feet we encountered rain... Straight down to 8,500 feet, no future in that... Backtracked to an open coal mine in the sunshine, and soared back up to 10,500 feet, now I could make a bee line to the Cranbrook valley over the Rockies.

The morals of the story is that when you degrade the performance of your aeroplane you had better be able to fly it accurately, and when it all looks like you’re doomed don’t panic, fly the aeroplane.
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By A4 Pacific
#1839209
I don't care a hoot about insurance where owning your aircraft if it resulted in a crash then it is one owns tough luck.


Bearing in mind you would probably be overweight because you are taking someone with you, that might look a bit ‘cavalier’?

As you say. Who gives a hoot what happens to you.
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By Trent772
#1839297
A4 Pacific wrote:
Thought it felt a bit woolly at the time but it flew OK. Thanks Mr Aeeerrboooos :pirat:


It’s an Airbus. Are you saying there were times it didn’t feel woolly? :lol:


Pah....... No doubt you are a Tractor driver...... :cyclops:
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By Rob L
#1839321
I fly a high-wing strut-braced classic monoplane aircraft that was originally designed to have a MTOW of 1500lbs, but was only certified at 1200lbs (the certification costs at that weight were cheaper back then).

Since then, there is a 2-stage STC to increase the MTOW either to 1280lb (which I have incorporated) or to 1500lbs MTOW (which I may do in the future).
Considering the empty weight is about 830lbs, those additional 80 or 300lbs to the MTOW are a HUGE increase in the usable load!

The STC involves very few structural mods (all the wing and strut bolts are the same diameter, for example).

Summary: Most aircraft are well-engineered for weight; Trans-oceanic GA ferry permits are regularly approved at 150% of MTOW (Flyingfemme please comment).

But some (including mine) are a bit testy on the location of the Centre of Gravity (CG) at those high weights.

Rob
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By Iceman
FLYER Club Member  FLYER Club Member
#1839336
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By riverrock
FLYER Club Member  FLYER Club Member
#1839384
flyingearly wrote:I'm sure that this exactly conversation/question came up a couple of years ago on here. The 'conclusion' (though not sure how robust it was, or informed!) was that being overweight would only invalidate the insurance if the fact you were overweight contributed to the accident.

https://www.legislation.gov.uk/ukpga/20 ... 10/enacted

The language is far from plain, but I believe it essentially says if risk is the same, despite something not done, insurer is still liable.
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By Trent772
#1839486
A4 Pacific wrote:Trent772

How many passengers does an A330 carry? A few will be overweight, a few will be under. Each individual passenger (and their luggage) being a fraction of the total. Not to mention your 4 or 5 tonnes is probably 1-2% of the gross.

Very different kettle of fish when you’ve got two beer balloons in a Piper Cub.



Our 200's had around 325, the 300's had up to 405.

We operated at 230 tonnes gross, but the aeroplane was certified heavier than that.

The percentage and leeway is there, but I know what you mean about the N of D, even though it is a vile human remains/CRM type phrase.

When you rock up at POP and the agent says we have 10 tones of freight..... I stare him in the eye and call him a rude Danish name and ask again. 12.5, I have a little for myself he says.

All in the past now - good times indeed.
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By NDB_hold
#1839611
I did encounter a C152 which according to the w&b schedule was out of limits with one or two people and with any amount of fuel. Centre of gravity always too far forwards. CFI checked it and same result. That ac no longer at the club so I don’t know what the upshot was...
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