Hard Landing Question

MiloDublin

Sometimes you land and the plane just lightly 'kisses' the runway, othertimes there is a really loud jolt/noise which sounds like something is under considerable pressue and possibly breaking. What is that sound and how is the wheel support designed to withstand such hard landings? Is there a point where it could fail?

highlydebased

Landing gear are designed for loads far heavier than your average landing. The noises on touchdown are typically rattles in the cabin, luggage shifting etc.

folbotcar

It depends on how hard the landing is. Aircraft are designed to take certain loads and what you might think is a hard landing may only be a 'firm' landing. In the event of a genuine hard landing and inspection might be required or at worst be 'recovered' off the runway.:eek:

The undercarriage however is very sturdily designed to allow for careless pilots.

Dublinflyer

An old clip but Kerplunk!

https://www.youtube.com/watch?v=4c0eaofrdTo

billie1b

Dublinflyer wrote: »

An old clip but Kerplunk!

https://www.youtube.com/watch?v=4c0eaofrdTo

Jaysus, they certainly put her down

Dublinflyer

billie1b wrote: »

Jaysus, they certainly put her down

It must have made some sound inside the cabin.

BeardySi

Bloody hell! Windshear??

andy_g

Just severe winds that day

Autonomous

I remember a few years ago on a Ryanair flight into Shannon, you'd think the pilot was trying to make a hole in the runway... some jolt when he put her down.

ProfessorPlum

Treadhead wrote: »

Bloody hell! Windshear??

Crosswind coupled with the very steep glide path (5.5 degrees) and short runway makes for a difficult approach into LCY. But that was a bit extreme alright!

Just in reference to the video of the hard Swiss landing at city

http://aviation-safety.net/database/record.php?id=20070818-1

http://www.flightglobal.com/news/articles/video-and-pictures-swiss-has-removed-damaged-avro-rj100-on-floating-pontoon-at-london-216951/

windowspotter

To the pilots & various other knowledgeable heads on here...could the pilot have done a better job here or aborted landing after first touch? Genuine question rather than trying to knock a man obviously much more skilled than myself

flazio

Did I hear somewhere that it's all to do with fuel saving?

eatmyshorts

flazio wrote: »

Did I hear somewhere that it's all to do with fuel saving?

If you did, it was from someone talking out of their arse!

Its a common misconception that a soft landing = a good landing. In fact it's mostly the other way round.
Holding off in the flare to get a soft touchdown eats up runway length at a great rate.
A good firm(ish) landing gets weight on wheels and spoiler deployment quickly, enabling the most efficient braking and lift dumping.
This is especially important on wet/contaminated/short runways or on crossword conditions.

martinsvi

windowspotter wrote: »

To the pilots & various other knowledgeable heads on here...could the pilot have done a better job here or aborted landing after first touch? Genuine question rather than trying to knock a man obviously much more skilled than myself

the very first book that every pilot starts their career with - Trevor Thom's flying manual vol 1. says - if you bounce after landing, there's a good chance it will keep bouncing and that's the last thing you want. It suggests that you DO have to go around.

However given the conditions and workload that pilots face in these situations, they rarely ever go around and it's difficult to blame them for that.

Irish Steve

Its also important not to hold off too long in the larger (longer) jets like the 737-800, as if too much speed bleeds off in the flare, there is a significant risk of a tail strike, which can and does do damage.

The 800 only has a 10 Kt margin between landing speed and tail strike risk speed, so it's a lot better to make a "positive" arrival than to try to do a greaser landing. And yes, a firm landing makes sure that the wheels are turning, especially on wet or icy runways, and makes sure that the wheels spin up to speed quickly, as well as making very sure that the switches that detect on ground get a solid change of state, so that things like spoilers and thrust reversers can be deployed.

In the early days of the Airbus, a gentle landing on an icy runway meant that the detect switches did not correctly detect that the aircraft had landed, and an accident was the result. (for more details search for "Report on the accident to Airbus A320-211 Aircraft in Warsaw on 14 September 1993.")

That said, there are firm landings, and there are landings that come close to qualifying as a burial. You know it was a bit firm when all around you give an involuntary "oooffff" as it hits the runway.