Definition of hard landing-maintenance
 

Hello,

Does anyone know at which point a maintenance inspection should be performed for a hard landing ? Out of curiousit.

A maintenance definition of a hard landing on a A-320

After how many g´s ? ( ref AIDS )

Thanks in advance

From A-320 AMM:

Thanks Stuck

don't forget to take 1g off, so the actual g that determines a hard landing is 1.6g, 1+1.6, as 1g is with us all the time.

I hope that the AMM has more to say on the matter since the extract provided by Stuck suggests that if your aircraft lands with a weight greater than the Maximum Landing Weight then it is not classified as a Hard Landing or a Severe Hard Landing...

While I won't reproduce it here, the B777 and A330 AMMs for example, have a great deal to say about hard, overweight or hard/overweight landings. I suspect this is the same throughout all AMMs.

For the B777, some things examined are vertical acceleration sample rate, peak 'g' value, roll angle, (for side-loads), aircraft weight and so on. Boeing leaves up to the pilot the determination of whether or not a structural examination is required.

Most airlines will set their own criteria as to what constitutes a hard landing.

Er, no, a hard landing is just that, a bang-it-on landing. If you do a greaser whilst overweight, that is not a hard landing. An overweight landing yes, but not a hard landing.

Wow, 840 fpm to classify as a hard landing? That'd surely rattle some teeth :D

840fpm are classified as a severe hard landing.

...and if below a certain rate-of-descent (A330, 6fps/360fpm), an overweight landing check may not need to be done.

Again, in my airline and I'm sure a it's the same in many, an overweight landing requires an inspection regardless of the descent rate. Otherwise a crew can simply state that the descent rate was within limits. If you were running an airline, would you be happy with that policy?
We also do not allow a crew to report a 'firm' landing or a 'suspected hard landing'. This is on the basis that it is either a hard landing or it is not. After the crew report the incident it is then up to the QAR captured data to determine if they were correct or not.

PJ2. Sorry, just re read your post. Maybe you meant that if the descent rate was within limits according to the data. In that case I would agree with you.

Yes, that's what I meant. In many operations, maintenance interrogation of the airplane's data can be done quickly and easily (wireless transmission) to confirm the rate of descent.

I think we are on the same page with this, as far as the AMM goes. I disagree however with the requirement in the AMM's hard-landing section (B777) that a hard landing must be reported by the pilot before the airplane is handled as per the AMM. If no report is made then the hard landing didn't occur. These days though the airplane may self-report. I know some A330's that do.

So in view of that, I like your carrier's policy - either declare it if it was a hard landing, or release the airplane to your colleagues who are taking it out next.

The reason I disagree is because today there are entirely objective ways of quickly determining whether a landing was hard and what the roll was at touchdown etc so the metrics in the AMM can be accurately determined and a decision made on the spot.

The B777 vertical 'g' parameter is sampled 10x per second so the specified vertical acceleration in the AMM could easily be determined from the data in support of a pilot's report.

The obvious difficulty arises when, for perfectly reasonable reasons no report is filed especially where there is some doubt, and the airplane's FOQA data later reveals a heavy landing, with roll, etc. In this day of rich data collection I don't see how to square the two.

Several very heavy landings have occurred on Airbus A320/A321 aircraft and the airplane has gone flying again, (discussed elsewhere on PPRuNe). The maintenance people dealing with the pilot report (when made) did not know how to interrogate the ACARS/ACMS for the Load 15 Report for the SSFDR-recorded vertical acceleration parameter. These landings were in excess of 3g's and resulted in gear changes. In at least one case the airplane continued to fly for almost two weeks before being grounded after the FOQA data was read.

Where I work we have a somewhat punitive culture. I do not always agree with this but the emphasis is put on reporting integrity which is not a bad thing. If a report has not been forthcoming and the airline finds out what has happened by other means, then the penalties for the crew are far more severe. But we operate in an environment where unions are there in name only so I understand that this type of culture might be impossible in a more democratic airline.
Another example would be a taxi route error where a crew might be criticised and suffer a small censure but if ATC reports the incident and the crew didn't, there is all hell to pay. Personally I think this is generally a positive thing.
Sorry, going off topic somewhat....

I think people have missed the point about my comments about the AMM extract:
The way it is stated is that regardless of how you land with a landing weight greater than the Maximum Landing Weight then the landing is not classified as either a hard landing or a severe hard landing...
(the word and is very important in this context)
Which raises the question - does the AMM say anything about landing with a weight greater than the MLW?

(I know this may seem somewhat pedantic but I am a programmer by profession and such holes in rules are something I tend to notice)

Hello LurkerBelow;

In response to your question, yes, the AMMs with which I am familiar (A320, A330, A340, B777) deal with Overweight Landings in an entirely separate manner from hard landings.

Necessarily, the two combine in the AMM should such circumstances obtain.

Normally, the two events (hard landing, overweight landing) occur separately and are printed / handled separately in these AMMs.

The A330/A340 QRH requires a touchdown rate of descent of 360fpm or less. I know from experience, (35T above MLW in an A340) that if the touchdown is =< the MLW, no overweight landing check is required. We were on our way in an hour. Also, maintenance was able to see the data from the ACARS.

This kind of relief would be type-specific, likely from the manufacturer in coordination with the regulator. I don't know whether "Landing Weight" works the same as MTOW which is sometimes just defined as what the airline will pay for because limits aren't always structural but I have no idea how that works in detail.

It all depends on the drivers and the the people in the office. Unfortunately often if if the pilot does not report a possible hard landing and no one is reading or flagging the ACARS report they can squeek by. We usually use ACARS to determine if it was not a hard landing, if it was the DFDR get's pulled and we start performing the inspection.

A little off topic here but this is a dangerous situation we see often in a PDIS. "encountered heavy/moderate turb, A/P #1 disengaged and the aircraft lost 600ft". The regular line maintenance only see's an autopilot problem. It is normal often for an a/p to kick off in turb, the threat is the turb sometimes get's overlooked by the avionics guy sent out to the plane. The proper procedure should be for the pilot to make 2 log entry's in the first place. As an A/V tech I have had to generate a 2nd log entry often to ensure the turbulence is addressed. Multiple problems should never be listed in a log entry anyways.

Where I get landing reference at fpm for king air B200 C90, caravan C208, cessna172 and etc ....