Overweight landings and aircraft checks

[QuEsT147]

Hi all

had a discussion with a coleague recently regarding overweight landings and following aircraft checks. AFAIK you dont need to send the aircraft for the inspection if vertical speed at touchdown is less than 360 ft/min at MTOW, no matter how many overweight landings you make.

But he said, that even if this is true, no limit values exceeded, you still have to send the aircraft for inspection after certain number of overweight landigs, regardless of how low the touchdown vertical speed was.

Who is right?

Thanks for your opinions, gentlemen

QuEsT147

[TURIN]

What does your AMM say on the subject?

[QuEsT147]

Hi Turin

unfortunately, I dont know, since I have no access to any AMM. I am just aviation enthusiast, using this perfect forum to gain more knowledge and hoping that you, professionals, will answer my questions

Anyway, thanks for your reply

QuEsT147

[extreme P]

AERO - Overweight Landing? Fuel Jettison? What To Consider

"The Boeing airplane maintenance manual (AMM) provides a special inspection that is required any time an overweight landing occurs, regardless of how smooth the landing."

[Occy]

I would suggest at any weight, a touchdown with a vertical speed of 360 ft/min would probably warrant some kind of inspection.

[QuEsT147]

Hi all

Thanks for your answers, much appreciated

QuEsT147

[glhcarl]

It is called an "Overweight Landing Inspection". Note that "Landing" is singular, ie no "s" on the end.

[Intruder]

I would suggest at any weight, a touchdown with a vertical speed of 360 ft/min would probably warrant some kind of inspection.

How would one know the rate of descent at touchdown?

There is also such a thing as a "hard landing inspection" in addition to the overweight landing inspection...

[ei-flyer]

intruder,

you may happen to glance at the vsi, very easy to interpret in a millisecond when you have substantial time on type. in any case, following a hard landing, this can be obtained from the FDR.

[john_tullamarine]

Some thoughts -

(a) MLW is a TC/AFM limit so any overweight landing contravenes the aircraft limitations which has reporting and followup consequences. For those who think otherwise, do you, then, routinely, and intentionally, takeoff at weights in excess of the MTOW/RTOW ? .. same philosophy applies.

(b) the vsi, very easy to interpret in a millisecond

except for the PEC's doing strange things in ground effect. VSI reading is not much use.

(c) this can be obtained from the FDR.

generally not achieveable due to inadequate sample rates

[boredcounter]

QAR

In the case of a 'Hard Landing' would this be downloadable to assist?

Can a Boeing type engineer please confirm for me:

Hard landing (as I have called it) = excessive sink rate/g for want of a better definition.

Heavy / Overweight landing, the same thing, exceeding the MLW of the airframe.

In a previous (non-flying, non-engineering, hell yes, Ops ) life, "Heavy' was excessive sink/g and 'Overwieght' was just that and a hard landing was the F/o's as reported by the Captain.

Now I work with Boeings, thats why I ask for clarification.


Thanks in advance,

Bored

[Quality Time]

I don't think that disregarding MTOW/RTOW and landing over Max landing weight reflect the same mentality.A line pilot may occasionally expect to do the latter and be trained to do so under some circumstances.

One of them is clearly considered and accounted for because for most aircraft the MTOW is significantly higher than the MLW. The manufacturers consider this and account for it and it may well be discussed in Operations manuals. Of course it has some implications as you suggested.

Taking off over MTOW is not something normally considered.

[TURIN]

How would one know the rate of descent at touchdown?

The Airbus family and B777 have on board data systems that record various parameters during the 'touchdown'.
Some airlines will have the system programmed to automatically printout a copy in the flight deck and/or send an ACARS to base for evaluation.

The Boeing is pretty straight forward to interpret.
The Bus on the other hand requires a masters degree in quantum mechanics and relies heavily on the Heisenberg Uncertainty Principle.

[BigJoeRice]

"Can a Boeing type engineer please confirm for me:

Hard landing (as I have called it) = excessive sink rate/g for want of a better definition.

Heavy / Overweight landing, the same thing, exceeding the MLW of the airframe."

See my response to this in the Engineers section.

[john_tullamarine]

I don't think that disregarding MTOW/RTOW and landing over Max landing weight reflect the same mentality.A line pilot may occasionally expect to do the latter and be trained to do so under some circumstances.

I am utterly astounded that we are having this discussion ... if the above be true, then which other limitations in the AFM limitations section are optional .. rather than required as part of the Type Certification ?

Caveat - we are talking non-emergency situations here.

[Quality Time]

JT

' Utterly astounded ' Maybe a little dramatic there John?

How do you define 'emergency' ? Does it have to be a 'Mayday' call or will a 'Pan' do? Is the passenger really having a heart attack or should you hold overweight until you find out for sure?

The point I was making is that I never expect to deliberately Take off over the limit but I have and may again land over MLW.

In fact I was in the company of a very senior technical pilot from a certain well known aircraft manunfacturer the other day and I put to him the scenario in the other thread on this forum about overweight landings. He didn't hesitate - he would land unless it was specifically prohibited by the applicable rules.

BTW IMO returning to land at the departure airport for a technical reason is not the same thing as 'in flight re-planning' as defined in operations manuals I have seen. The latter normally occurs on long flights with a change of destination and is effectively the same as planning the flight on the ground so it requires similar considerations. EG Landing factors.

In any event our Ops manual is quite clear that different factors apply once airborne to those at the planning stage on the ground.

[john_tullamarine]

Maybe a little dramatic there John?

I don't think so.

How do you define 'emergency'

One could be facile and cite the regulatory words for a given jurisdiction. However, a simpler view is anything which the commander considers warrants such a declaration.

In exceptional cases

.. which, to me, infers an emergency situation ...


Several points are pertinent -

(a) MLW is a limitation, no different to any other

(b) if you land in excess of MLW then you may be called upon to justify your actions either to the Regulator or the judiciary .. especially if a mishap ensues during the event

(c) to avoid the problems inherent in (b) I would only consider an overweight landing if I had a defensible risk based argument and could argue that the circumstances warranted declaring an emergency. An alternative acceptable circumstance might be one which involved the declaration of mercy flight provisions.

IF your ops manual has been Regulator approved and permits/directs an overweight landing in specified circumstances then that is a different situation.

If your views differ, that's fine .. but I know which option offers the best chance of a peaceful night's sleep .... perhaps you ought to seek local jurisdiction legal advice ?

Philosophically, I see no difference between busting the MLW limit for convenience and breaking any other limitation or regulatory requirement.

Perhaps I'm just an old dinosaur brought up in a different world ?

Hopefully some of our legally competent folk will offer an opinion or two ..

[Quality Time]

(a) MLW is a limitation, no different to any other

But it is different.
Why do Boeing and Airbus both give guidance on overweight landings?

If your views differ, that's fine ..

My views are far from isolated. They developed from listening to lots of other peoples opinion and experience and company guidance- including for example the gentleman I mentioned in my previous post. If I had discussed this scenario with my friends (Airline Captains)and they all said 'no way could you land' I would have to rethink my position. That has not been the case. Some would hold to MLW, some would land immediately and others would hold to an intermediate weight to increase margins if required.

From a technical point of view I don't think there is a major issue. There appears to be significany divergence on the requirement to do so and any consequences thereof.

Finally I am not suggesting for one minute that landing overweight is optional under normal circumstances but I don't think you have to be on fire with an engine out before you can do so.

BTW would a 'legally competent' person make the same decision as a competent aircraft Commander?

[Quality Time]

Sorry a little OT for this thread maybe we should combine the two threads?

[Tinwacker]

OW

Just had an A330 landing OW after a divertion into BOM due 'All toilets inop'.
Not an emergency but then to the person busting a bladder it was.

OW weight inspection carried out.
The AMM for Hard and OW landing checks might at first hand seem a touch difficult but to follow the printable report 15 and the AMM graphs it's quite easy even for an oldr

TW