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-   -   Hard landings, definition (https://www.pprune.org/tech-log/67012-hard-landings-definition.html)

aloneincommand 16th September 2002 01:23

Hard landings, definition
 
I don't mean to be the carrier of bad fortune for those who read this question and dare to give an answer, but really need to know :
The definition of a hard landing:confused:
Thank you in advance for your answers.

farrari 16th September 2002 05:09

when your Pax reading glasses come off!

mcdhu 16th September 2002 08:29

Aloneincommand - been flying with hu, have we?!!

Just joking,
mcdhu

PAXboy 16th September 2002 16:07

To add a supplemental question ... Does a 'bounce' count as hard? My guess is not as it might be a gentle bounce?

Hard might depend upon physical damage to the undercarriage? Even if the shocks travel their full distance, if they continue to operate normally, it might still be regarded as 'OK'?

CaptainSandL 16th September 2002 16:50

I suspect that there is no official answer to this one, simply that if it felt hard then it was, so get it checked as a precaution. That said, I have some old training guidance notes that stated:

"Aircraft are certified for landings at 600fpm at max landing weight and 360fpm at max take-off weight"...
"A normal landing is 120fpm".

I must admit that until I had read this, I had thought that a normal (ie good) landing was almost zero fpm. Notice no mention of "g" which is just as well as my estimation of "g" is probably worse than my estimation of the flare height !

S & L

fireflybob 16th September 2002 19:17

I think the correct terminology is "heavy" landing rather than "hard".

It's all really very subjective but I guess the safest course of action if you are unhappy about an "arrival" is to report it on the tech log so that licensed engineers can do a proper check. That way we all remain safe whether or not it was heavy.

In the course of a flying career you are almost bound to get a few touchdowns which are firmer than you would like - nothing to be really ashamed of if you are doing the job diligently.

Capt.KAOS 16th September 2002 19:35

In my pax experience I would say roughly between 3-4 bounces until gravity finally wins.

Also I've noticed landings are harder in wet conditions, for the grip I guess?


Cheers

Capt.KAOS

Golden Rivet 16th September 2002 20:16

Boeing definition for 757/767 hard landing

Peak vertical acceleration exceeding 1.8G with FDR capable of measuring 8 samples per second, and 1.9G with FDR capable of 16 samples per second .

m&v 17th September 2002 00:49

Putting out all the pax o2 masks is a good index(once on the 727 at LGA)..Be wise to talk to MTC,they can at least check for leaks etc. 'Heavy' a different Situ',one has to explain via the tech log if one exceeded the above stated criteria.If one touched down smoothly used full reverse-judicious brakes,and all the runway,this might relieve MTC from a 'full' oweight landing check(in some cases 25manhours).
Cheers:rolleyes:

purr 17th September 2002 03:00

also,a hard landing is when

- there is silence until shutdown
- brain rattles at touchdown
- you take peek at the pax while
deplaning

mustafagander 17th September 2002 03:32

Back in the Good Old Days, the DC8 series had a little Al strip fitted to each MLG oleo at the bottom pointing up. Us groundies checked the strips each transit. If a strip was bent, you did a hard landing check, no ifs or buts. They were known as "lie detectors".

aloneincommand 18th September 2002 04:05

hardlandings
 
Ok, it can be heavy or hard, but, what kind of parameters should be considered to enter a report in the maint. logbook.

I have left it to my feelings, but it has turned out, that, according to the FDR we have been very close to a "hard" landing, and even, when I have been lucky enough to make a very soft landing (greaser, they call it) the FOQAS has detected high G's, and thus, my (our) landing technique has to be "revised", which has created a great deal of confussion among all the pilots.
That's why we are trying to fing the right technique to land the B-738. And stop a witch hunt in progres in our company.
Keep feeding us with your expertise.

Denti 18th September 2002 12:16

On our -300s we get a printout every time we do a hard landing (>2gs). I use the ACMS to check on some landings, just to train my feeling of the gs i produced. It's sometime really difficult to judge it correctly, a thump might feel like 1,3 or so but is only around 1,15g, but it might be up to 1,5. A greaser is not a good landing per se, but it is around 1,01 to 1,10g or something.

Young Paul 18th September 2002 13:27

Presumably "normal" normal acceleration is 1.00 g, anyway, so it's the value above this that you are interested in.

reverserunlocked 18th September 2002 13:39

A greaser is sometimes the worst thing you can do.......

It might be nice to float down the thing more smoothly than putting a baby in a cot, but that may well be at the expense of having two-thirds of the runway behind you and you've not even got the reversers out....

I'd rather take a firm one in the touchdown zone than 'grease' into farmer giles field at the other end.....


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