What is the definition of a 'hard landing' please?

[FWOF]

Flying from Amsterdam to Aberdeen last Thursday, not far off landing and we seemed to zoom forward a little, and engine noise increased. It was raining so I was expecting a 'firm' put down ... however, we seemed to land extremely hard, causing most passengers to exclaim. I bit my tongue and got a heck of a jolt in the back. I then wondered if we were ever going to stop or maybe take off again. Probably sounds dramatic but I am a newly fledged 'not-afraid-to-fly-anymore' person, and fly four flights a week.

I'm sure this landing was all within perfectly normal parameters, but I do also recall a few weeks previous the Captain explaining we would be landing and braking sharply due to the weight. It lessened the shock, and it's always nice to hear from the man/lady at the front!

So, all I'd like to know, so that I can absorb and file the info in my brain, is what is considered a hard landing and can we expect to be plonked down a bit more firmly than usual when it the weather is somewhat inclement?

[Pontius Navigator]

I think it fair to say that was a hard landing.

You will expect a firm landing in wet and windy conditions. Clues will be a late sighting of the ground and small scudding clouds below the main clud base.

The wings will rock and the plane will lurch from time to time. You will expect this more at the regional airports as the smaller aircraft will be affected more than the large ones.

What type was it?

I am not sure but I suspect that a prop aircraft may also be more affected as prop wash adds lift and wind sheer may well destroy lift more on one side.

[FWOF]

Was a KLM 737 ... am used to bad weather in those as much as I am being bashed about by the slightest breeze in a Fokker 50!

Was an unusual landing, for me anyway. Maybe being seated in the last row at the back also made it feel harder?

[G&T ice n slice]

The sequence you describe sounds fairly normal.
I think a 'hard' landing is one that bends something.

I am going to guess short-ish wet runway & possibly a slight tailwind component.

And, yes, back row of the 737 does seem to magnify every little bump, shudder, pitch & roll.

((fwiw a colleague of mine always used to choose the back row. when I asked why he said "you ever heard of an airplane backing into a mountain"
[He was an ex US marine]))

[Final 3 Greens]

FWOW

A hard landing is defined by technical parameters.

I doubt that what you experienced was a hard landing in this sense, although it was no doubt unpleasant to experience.

I once had a similar experience on a 767-400 and had an egg sized lump on my head from the bulkhead behind.

Last week I took 3 flights where I sat over the wheels and the landings felt like ....

737-800 - Kaboom!

737-400 - bang

RJ85 - no sensation of touchdown, just an increase in noise as the wheels spun up

All three approaches felt to be stable and controlled (as far as one can judge through a porthole in the back), but the landings felt different.

So I think that aircraft type does play a part - IIRC professional pilots have posted that the 737-800 has firm main gear oleos and the landings feel harder as a result.

[FWOF]

Thank you for your inputs, they have made interesting reads. As I say, I'm a frequent flyer and this is the first time I've experienced such a landing. As I said, I'm sure it was all within normal parameters, but it did prompt the question of what actually IS a hard landing. From what you say, if the aircraft is damaged, THEN it is classed as a hard landing.

[BladePilot]

One of the classics - Southwest Airlines No1 cabincrew member following a hard landing into Luv Field...

'ladies and gentlemen please remain seated until the captain attempts to taxi what is left of the aircraft to the gate'

or the little old lady who asked the Captain as she disembarked...

'say sonny did we land or were we shot down?'

:)

[Contacttower]

A hard landing is defined by technical parameters.

I'm sure a pro will be along soon to give a detailed explanation but I think a 'hard landing' is defined by a certain descent rate in fpm or g force. Some aircraft have hard landing detectors which would be inspected if it was suspected that a certain rate/deceleration had been exceeded.

I may be wildly out here but I'd have thought much more than 300fpm on touch down would feel pretty hard in a passenger plane.

[stevef]

[ I think a 'hard' landing is one that bends something.]

If my memory serves me right, a heavy landing (after which a specific maintenance inspection should be carried out) is one in which the vertical velocity exceeds 10ft per second. A 'hard landing' will not necessarily damage anything as the undercarriage will have been certification tested to absorb loads of up to the figure mentioned above. Anything in excess of that may well cause transmitted damage to the airframe and/or engine pylon attachments.

Addition after reading Contact Tower's post:
Yes, I've seen inertia switches fitted to landing gear legs - a steel ball pops through a plate spring to indicate that a certain 'G' loading has been reached and exceeded.

[SNS3Guppy]

A hard landing is defined by your maintenance publications, and requires an airframe inspection in nearly all cases. What constitutes a hard landing depends on the type of aircraft and the circumstances. A descent rate at one weight may not be a hard landing, while the same descent rate at a different weight may be.

If you have to ask if it was a hard landing, it probably was...or at least it's best to get a hard landing inspection done, to be safe.

[c2lass]

When I read your thread title I thought to myself anything that lands at ABZ, then I read your post and saw that you did land at ABZ :cool:

Seriously, I dont fly as much as you but it seems to me every time I land at my home town of ABZ it is always a very bumpy decent and a hard landing, not as bad as you describe though. Yes I know it is a short runway as well.

However, we flew Lufthansa earlier this year to from LHR to MUC and both landings were probably the hardest I have experienced and in particular on the return journey back to LHR we had suffered bad turbulence then a terrible landing which caused a few people to shout out and the woman opposite me to continuously make the sign of the cross!!!

Similarly, a couple of weeks ago flew ABZ to LHR and not a hard landing but when the captain or co pilot put the brakes on that was extremely severe and I do not think I have ever experienced being jolted quite like that. I began to wonder if he braked so hardly as he was going to overshoot the runway, but that was not the case. Probably all quite normal really.

[Contacttower]

I began to wonder if he braked so hardly as he was going to overshoot the runway, but that was not the case. Probably all quite normal really.


Perhaps he got runway 34 mixed up with 32? :E

[Der absolute Hammer]

Many aircraft have a type of accelerometer in the undercarriage bays.
After a reported hard landing, this is checked by engineering. Depending on the reading, this will tell them what needs to be done in checks and if it was a hard landing at all or just a whiff from a sensitive backside.

[c2lass]

"Perhaps he got runway 34 mixed up with 32? http://static.pprune.org/images/smilies/evil.gif "

Not sure what that means but what I should have added was no sooner had we had the very hard brakes, we then had a very sharp turn off the main runway, so maybe he nearly overshot his turnoff, whatever they are called.

[FWOF]

Have been flying in and out of ABZ since moving there in January, and this was the only landing that caused me to post. I'm used to the bobbing up and down, espcially in the smaller Eastern and FlyBe planes, so that's never been an issue although at times maybe a bit of an eyebrow raiser! Likewise, I've also experienced firm braking, but nothing to ever make me question it. I know each flight is completely different, and that's something I happily accept with no question and even this landing I'm sure was nothing overly outlandish. It just prompted me to ask the question. Again, thanks for the input.

[John R]

The "heavier than normal" braking technique can be used to take an early runway exit, especially at busier airports. You notice it quite often at Gatwick, for example.

[Chesty Morgan]

32 is the one the helicopter chappies use and is, therefore, not very long!

[MONSIEUR]

As absolute hammer said, some aircrafts have acceleration sensors measuring the G forces on landing and during flight (for turbulence). On our aircrafts (757/767) We can access the info after landing, and any landing over 1.8G is considered a hard landing and requires an inspection by an engineer.

[Capot]

A hard landing is defined by technical parameters

Yeah, yeah, we know all that. Accelerometers or whatever. (1 'l" or 2? Anyone know?)

But in reality a hard landing is one when the consequent damage is so bad that the aircraft must be taken out of service; for example if the U/C legs are sticking up through the wing, or the dihedral has increased dramatically, or both, or if the fuselage is banana-shaped..

Anything else is "firm" and perfectly OK; if the pilot is quick-thinking, it's invariably been done purposefully for a good airmanship reason such as avoiding aquaplaning.

[strake]

All very interesting but the real definition of a hard landing is one where you walk away from the a/c but not necessarily having used the stairs or pier....

[Megaton]

For info we (Airbus operator) normally regard Aberdeen as a fairly short runway and certainly wouldn't want to waste any of it by "greasing" it on! Normally also use medium autobrake to ensure we stop comfortably before the end.

[Pontius Navigator]

I recall once landing at Inverness, Dan Dare IIRC. He dropped it in from about 30 feet. The chap next to me had a bad back from an earlier ejection and it hurt his spine.

If anything like that does happen you must speak with the cabin director and get it logged as it could get worse a day or so later.

[SNS3Guppy]

Yeah, yeah, we know all that. Accelerometers or whatever. (1 'l" or 2? Anyone know?)

But in reality a hard landing is one when the consequent damage is so bad that the aircraft must be taken out of service; for example if the U/C legs are sticking up through the wing, or the dihedral has increased dramatically, or both, or if the fuselage is banana-shaped..

Anything else is "firm" and perfectly OK; if the pilot is quick-thinking, it's invariably been done purposefully for a good airmanship reason such as avoiding aquaplaning.


No, no, you don't know all that. You are...wrong.

A hard landing is not defined as one is which "damage is so bad that the aircraft must be taken out of service." In fact, that's utterly ridiculous.

Again, even though you "know all that," the aircraft maintenance manual will spell out the parameters for a hard landing, and the inspections required thereof.

In fact, one of the hallmark purposes of conducting a hard landing inspection is that any damage is most likely not apparent, and for that reason a detailed specific inspection is performed. But yeah, yeah, you know all that, right?

[Pugilistic Animus]

SNS3Guppy--- tellin' like it 'really is' as usual:ok:

[Wader2]

All very interesting but the real definition of a hard landing is one where you walk away from the a/c but not necessarily having used the stairs or pier....

No, no, that is a successful landing where you can walk away from the aircraft.

[BladePilot]

BA 777 into LHR now that was a 'hard landing' damage most definitely apparent!

SNS3Guppy,
Can you give us a bit about how the manufacturers recommend landing particular types in bad weather and also how some companies have a prefered landing technique in certain weather such as crosswind landing:ok:

[doncas]

The best definition that can be given is objective rather than subjective, i.e. What might feel hard to one person, might be quite normal to another etc. The definition given in the AMM is:

"An indication of a hard landing on the main landing gear is a peak recorded vertical acceleration that exceeds 2.1 G (incremental 1.1 G). "

Also, the onus is on the pilot:

"The pilot must make a decision if a structural examination is necessary."

I have often met crews who gave me a verbal report on their landing. If they even think that they might have had a hard landing (in their own opinion) I will carry out an inspection.

D

[SNS3Guppy]

Taken verbatim from the Boeing mx manual:

For landing at or below the maximum design landing weight on
airplanes with flight data recording systems capable of at
least least eight (8) samples per second, the following can be
used: An indication of a hard landing on the main landing gear
is a peak recorded vertical acceleration that exceeds 1.7 G
(incremental 0.7 G). This vertical accelerometer data must be
measured by the flight data recorder accelerometer at a data
sampling rate of at least eight (8) samples per second. This
vertical acceleration G-level threshold is valid for a
conventional landing with impact with no more than two (2)
degrees of airplane roll, main landing gear touchdown first and
normal rotation onto the nose gear. For a hard landing that is
a hard nose landing or is accompanied by more than two (2)
degrees of roll at the time of main landing gear impact, The
recorded peak acceleration can be significantly less than 1.7
G, but a hard landing inspection may still be necessary.

(b) For landing at or below the maximum design landing weight on
airplanes with flight data recording systems capable of at
least least sixteen (16) samples per second, the following can
be used: An indication of a hard landing on the main landing
gear is a peak recorded vertical acceleration that exceeds 1.8
G (incremental 0.8 G). This vertical accelerometer data must
be measured by the flight data recorder accelerometer at a data
sampling rate of at least sixteen (16) samples per second.
This vertical acceleration G-level threshold is valid for a
conventional landing with impact with no more than two (2)
degrees of airplane roll, main landing gear touchdown first and
normal rotation onto the nose gear. For a hard landing that is
a hard nose landing or is accompanied by more than two (2)
degrees of roll at the time of main landing gear impact, The
recorded peak acceleration can be significantly less than 1.8
G, but a hard landing inspection may still be necessary.


A pilot may still request a hard landing inspection if he feels the landing was hard, though for obvious reasons many won't make that request.

I had a firm landing about six months ago in which structural damage occurred. The damage wasn't the result of the landing, however...it was due to a couple of missing bolts that allowed a part to give way. Never the less, the company grounded the airplane for a week, pulled the flight data recorder, and looked at all my previous landings and the recent history of the airplane, before deciding that it wasn't a hard landing. They went ahead and performed a hard landing inspection anyway. I didn't request it and didn't need to.

[jamestkirk]

you should feel mine!!!

I mean landings, not bodily parts as that would be vulgar.

[marsie]

Apparently it can be down to someone moving the runway :) A couple of years ago on a flight into Liverpool on a 737 we approached from the south west on a beautiful clear day. I was just expecting the flare when we hit the runway with bang. A ceiling panel over the aisle came loose and several overhead lockers flew open (fortunately nothing really heavy fell out. There was quite a lot of screaming and cursing, though). We braked normally and came to a stop at the end of the runway, then the captain came on the PA, chuckling. He said, " my colleague" (who was the PF) " informs me that the runway was six feet lower when we left".

[smith]

When the fillingsa fall out your teeth!!:}

[Lookforshooter]

A hard landing(for those that actualy fly people) is one where the passengers look at the pilots like they screwed up afterward.

[SNS3Guppy]

A hard landing(for those that actualy fly people) is one where the passengers look at the pilots like they screwed up afterward.


There you have it, folks. The technical definition, provided courtesy of a genuine microsoft simulator game player.

[Capot]

SNS3Guppy

Here's something you may not know.

Not every post on pprune has to be taken as a serious offering on the subject, to be duly flamed by an expert such as yourself. If you want technical seriousness go to Tech Log and mix it with real experts.

Even here, some of those you flame so swiftly with your towering expertise may even know as much as you.

No, scrub that, it's not possible.

Mind you I've been modded once for making fun of your reply to my last extant post on this thread and I guess it'll happen again..