Primarily for general aviation discussion, but other aviation topics are also welcome.
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By Lefty
FLYER Club Member  FLYER Club Member
#1839757
PeteSpencer wrote:ISTR at N LasVegas airport before a commercial jolly to Grand Canyon all the pax and their bags/cameras etc having to step on a set of bathroom types scales .

We were then walked out to the a/c and carefully sat in seats apparently to balance out the fatties No idea what Ac : about 9 seat high wing twin Rainbow Airlines .


That will have been a twin otter fitted with special “panoramic” windows that bulge outwards to give pax a much better view almost straight down.
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By akg1486
#1839895
Trent772 wrote:Having operated 3 large single pistons for skydiving in the 80's, MTOW and C of G are just suggestions !

In July 2019, a GA8-TC 320 with one pilot and eight parachutists took off from ESNU Umeå. Without the intention of simplifying the AAIB final report, I believe that the following picture is food for thought. The two diagrams are estimates (no actual load calculation was found) and they represent the aircraft before and after opening the door as the pax were preparing to jump.

Image

As can be seen, the CoG was too far aft of "the suggestion" already before opening the door and then moved back. The pilot and all eight passengers were killed. The word "plummet" is sometimes used in a lighthearted fashion on this forum, but it's actually what best describes what happened. The y-axis on the radar track below is in meters, since it's made by the military who for some reasons uses meters for altitude.

Image

Both images are taken from the final report published last year. It's not in English, but some of the pictures don't need translation. :shock:

https://www.havkom.se/assets/reports/RL ... apport.pdf

(As always, there were other reasons as well: inexperienced pilot, workload, etc.)
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By Josh
#1839918
I have always viewed performance as the area of aviation in ALL forms as taken too casually and most likely to kill people if done wrong. My friends at the AAIB agree and there are a large number of quite frightening big iron near misses (some involving contact with bits of lighting at the far end of the runway :shock:)

On big iron people tend to get away with it because the limiting factor is almost never all engines operating performance. As always, the key is understanding what’s going on and making a grown up decision.

Over here the most poorly understood area in GA I think is between structural and performance based limits. We simply do t have the variations of elevation and climate common in the states for example to make one aware. I went from Long Beach up to Big Bear in a DA40 with an instructor very early in my flying and that was a bigger lesson in understanding performance than any book could have given me. You may be in CG and W&B limits but if you don’t have enough Bernoullis to get airborne it’s all going to end in tears.

As always, the more planning you do before things get exciting, the less exciting things get!
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By MichaelP
FLYER Club Member  FLYER Club Member
#1839953
Nice surprise running out of elevator and having to add power in the Cessna 206 on amphib floats.
Did the calculations and found two up the CG to be forward of the forward limit... Added a 20 litre petrol can full of water secured in the rear of the cabin. That fixed it.

In the GA8-320 TC Airvan I added two 20 litre petrol cans of water secured in the rear of the cabin to bring the CG into a more reasonable range when we flew two up back from Ontario... Tipped the water out when carrying passengers.
(This aeroplane is for sale if anyone is interested, it’s on my website and controller).

If you fly many six seat aeroplanes such as Senecas you should likewise add weight to the rear to bring the CG into a reasonable range when flying without passengers in the back.
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By Josh
#1839969
Without wishing to be too “internet warrior”, perhaps calculating the numbers before running out of control authority might be a good idea?

Surely that lesson has been written in enough blood already?
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By MichaelP
FLYER Club Member  FLYER Club Member
#1839982
Without wishing to be too “internet warrior”, perhaps calculating the numbers before running out of control authority might be a good idea?


You are absolutely correct.
It underlined that thinking that being well under gross should not be a problem was an error.
One that I have not made since!

Since then I had an argument over a Stinson that likewise submarined its floats... Fortunately before it was flown off the water. It had previously launched from a dolly towed by a pick up truck and had alighted on the water.
The same pilot was going off the ramp when the floats dipped their bows below the surface, he had not noticed this when he arrived before, and I wonder why?
The pilot was a highly experienced seaplane operator and he argued with me about the reason.
I had the aeroplane weighed, the empty CG accurately found, and a mass was eventually fitted to the tailspring.
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By Josh
#1839993
One of the things that was really drummed into me when I was learning to fly seaplanes at Jack Brown’s was the importance of keeping the floats pumped dry at all times. CG, all up weight, slosh in manoeuvring flight. Pick your poison!
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By Trent772
#1839997
akg1486 wrote:
Trent772 wrote:Having operated 3 large single pistons for skydiving in the 80's, MTOW and C of G are just suggestions !



Airvan - Horrible aeroplane, not enough rudder, not enough power !

My original comments were tongue in cheek, we discussed the issues we faced and operated accordingly. It allowed you to play with aerodynamics though. All forward for take off, then - right - spread out to the back above 2,000' to take advantage of rear ward c of g. A bit like the 330 and other aeroplanes do by pumping fuel back to take the c of g back in the cruise.

Run ins were always interesting, but with 'skill and daring' as a good Training Captain used to say, we figured out a safe carry on. Some our less blessed brethren didn't and there was interesting shot of someone going over the tail of a Cessna 207 after the muppet stalled it as they were exiting.
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By MichaelP
FLYER Club Member  FLYER Club Member
#1840022
was the importance of keeping the floats pumped dry at all times. CG, all up weight, slosh in manoeuvring flight.


Most of the water goes into the rear chambers moving the CG aft as the rear of the floats are frequently under the water. If there is a problem in the bow chambers then there’s a leak.

When a seaplane is on the water you can gauge its balance by the way it looks.
A bit like with a Cessna 172 on wheels... It will tell you a lot by its attitude.

As for slosh, the chambers have bulkheads to reduce the amount of slosh to their short lengths. Floats should each be able to support the aeroplane on the water though often this is not true in Luscombes, and J3 Cubs that are often under floated...

Like everyone I had to learn, and in recent years I have taught the seaplane rating in Canada, both in floats, and in flying boats.
They are easier than tailwheel aeroplanes, but at the same time less forgiving in some circumstances, it’s a different skill.

There are plenty of stories...

One involved the pilot being encouraged to take hunters and their kills out of a lake.
He was unwilling, but the hunters told him the other guy flew out like this last year.
They crashed of course, and the hunters told the pilot that they got a few hundred yards further than they did the previous year.

This is very common in Canada, where young green ‘bush’ pilots are asked to take unreasonable loads in aeroplanes and crash for it.
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By aerial
#1840024
I am amazed by some people's attitude to aircraft loading.

I remember being told by an old pilot that there was probably nothing as dangerous as an overloaded Cherokee a few knots slow on the approach.
By NigelC
#1840371
As the performance data for most American aircraft in the 60s and 70s was written by the marketing department, even at the official max weight most weren't capable of the advertised performance and after 50-60 years funnily enough haven't got better.
If you need more payload buy/hire a larger aeroplane.
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By NDB_hold
#1840372
aerial wrote:I am amazed by some people's attitude to aircraft loading.

I remember being told by an old pilot that there was probably nothing as dangerous as an overloaded Cherokee a few knots slow on the approach.


It was a Cherokee 180 which gave me my only real overweight scare - I cheerfully loaded up me, 2 engineers, my son (aged about 13), fuel to tabs - all should be fine without doing a calculation, I thought - and a box of tools which I hadn’t weighed.

It was only when I started to slow down for landing at White Waltham that I noticed the handling seemed weird. Just as I realised what I’d done one of the engineers said ‘keep the speed up! I think we are rather heavy’...

Lesson learned without damage, thankfully.
By AprilDavy
#1840751
Iceman wrote
W&B issues affect all sizes of aircraft, sometimes for a very strange reason.


OMG...
My 82 year old auntie (bless her) is a "Miss" but definitely not a child's weight.

As a career software engineer (developing and testing safety and weapon
critical software for flight control and navigation for aircraft) we argued long over the damage that the inappropriate classification of software would have by inexperienced developers, i.e. in this case a language dependent use of Ms/Miss on the TO performance of an aircraft. and the lack of sample testing and proof of that program.

The simple analysis is one of dependencies...

The safe flight of an aircraft depends on; training, procedures, database integrity, human integrity, management integrity, finance officers, accountants, company directors, quality systems (all the stuff people laugh at) as well the proficiency of the engineering and aircrew personnel. In a modern airliner environment, there are numerous opportunities for an accident waiting to happen to be stopped by one of the many "swiss cheese" layers not having the holes in the right place. In Light Aviation, there is lesser emphasis on the aforementioned (hence the higher accident rate).

If one is flying an overweight aircraft, you have no idea how that aircraft will perform in a stall, recovery from an usual position, or a spin.

It is depressing that so many people on this thread talk about Take Off performance as if it is the only factor. If you don't take off, you may only run off the runway. If you do take off, then that's where the real risk occurs.
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By TopCat
FLYER Club Member  FLYER Club Member
#1840756
NDB_hold wrote:and a box of tools which I hadn’t weighed.

It was only when I started to slow down for landing at White Waltham that I noticed the handling seemed weird. Just as I realised what I’d done one of the engineers said ‘keep the speed up! I think we are rather heavy’...

Jeez, wtf was in the box?

It was either a heowge box of tools, with some really heavy stuff in it, or someone hadn't 'fessed up to rather a lot of pies. Or some assumptions weren't quite right.

A toolbox with some spanners in it isn't going to make the difference. Could there have been an additional spanner in one of the front seats?
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