Touchdown

[FSPFAN]

Almost allways after a flight the en flight report says that
my touchdown was too hard but I did land with a vertical speed
of less than 150-200 feet p/m.
Can enyone tell my how that's possible.

[WBHoenig]

What plane are you using? On a 747 that is pretty good, but on a Cessna, that will kill you upon impact.

[FSPFAN]

Mostly a 737 or 707.

[SWAFO]

Will is right. It varies depending on the aircraft you're using.

[FSPFAN]

How is that possible?
What's the difference?
And why gives a 747 you a better touchdown then a 737, the 747 is heavier?

[alphaone]

structual integrity...

[WBHoenig]

Exactly.

The 747 is a lot bigger than the 172SP. More mass to absorb the force of touchdown.



Post Edited ( 12-24-05 20:58 )

[Jetflyer]

Actually the C-150 can take quite a beating. I have done a good 300fpm on landing in them and it certainly won't "kill you". It is uncomfy and you
will bounce quite a bit a perhaps bend the strut about 1 micrometer but that's about it.

[Medic_Pilot]

Jetflyer wrote:
Actually the C-150 can take quite a beating. I have done a good 300fpm on landing in them and it certainly won't "kill you". It is
uncomfy and you
will bounce quite a bit a perhaps bend the strut about 1 micrometer but that's about it.

What he said.

150-200 FPM isn't a greaser, but If a 172 or 152 couldn't take an arrival like that, then there would be piles of scrapped planes and dead
people everywhere.

Greg

[MisterC]

I think i remember in Europe, for GA aircraft, the undercarriage is designed to absorb 700 ft per minute touchdown vertical speed. Over
this limit, you are not "killed", but the structural integrity of the gear, or of the plane is compromised.

Anyway, in France, we fly the 5% slope approach plane. I know it's not the rule everywhere, i believe especially in US, where the slope is
much steeper, but i am not sure.

So, at, let's say, 65 knots in final approach (my approach speed in DR-400), the vertical speed IN APPROACH is theorically 300-350
ft/min. 200 ft/min touchdown is huge, in my opinion.

On good landings on a grass strip, you just feel the wheels are scratching the grass some seconds before they really touch the ground. I
don't know exactly, but on this type of landing, vertical speed must be below 100 ft/min...

In FS2004, with GA aircraft, my touchdown speed indicated by FSP if generally about 100 ft/min, sometimes less.

[MisterC]

On my last flight, touchdown vertical speed : -45.4 ft/min.

[Jetflyer]

Well, I don't know the meaning of landings much below -100ft/m considering I am "Jetflyer" and in most jets a landing below 100f/min is a bad landing.
Firm on the touchdown zone is far better than a smooth greaser outside of it. GA pilots don't realise the speed of how much faster larger airliners
land and once you do you realise that greasers aren't what are important.

[MisterC]

I fly sometimes to altiports (in real life) and i agree the touchdown zone is more important than vertical speed at
touchdown.

On short strips, and no need to fly an airliner, it's the case in GA too, landings are often "hard" because the impact
point is the most
important. I don't fly airliners, but i have already landed at Lyon Brindas
http://www.sia.aviation-civile.gouv.fr/a...2.LFKL.pdf
and believe me, 390 meters available for landing is not that
much ! Especially when you're flying a plane given for 600 meters for landing !

But i know very good pilots that can put the airplane smoothly (ie with no impact sensation), exactly at the right
place...

[MisterC]

Jetflyer, in my opinion, a bouncing landing is not that good too

[FSPFAN]

I just came back from Schiphol, Amsterdam and they did an
automatic landing with a 737 and it still was a rough touchdown.
And I think it's true that a 737 give's you a harder touchdown than a 747.