Overweight Landing - When is it necessary ?
 

Hi

When does an overweight landing becomes necessary ?

When In non-normal situation is it a must to land as soon as possible even if the weight is above maximum for landing ?

Any references from Boeing / Airbus will be highly appreciated.

Thanks

Zenj

The simple answer is when the risk of staying in the air is greater then the risk of an overweight landing .

An on-board fire.

I suppose there is a perception that if a plane lands overweight that the gear will collapse and the tyres will burst and the brakes will catch on fire. Overweight landings are not inherently a dangerous exercise, they just put a greater than normal stress on the aircraft (but will be within their design limits)

But I'm sure there are much more suitably qualified people than me who can give you some technical details/numbers

I've never seen definitive written guidance on when to land overweight.

For me,

1. uncontrollable fire,
2. some other event where in my judgement landing asap is required,
3. medical emergency, where life is believed to be in danger.

I did an overweight landing back a few years ago on an A320 due to medical emergency. (Passenger heart attack-Doctor said hurry and get on ground.) After the landing and talking to maintenance, they said the big thing is how hard was the landing? If it is over a certain G limit or greater than so many feet per second down then there is a long inspection to do on the aircraft. If you are within the limits it is a visual inspection only.
We did a good landing and had only the visual....I never knew what happened to the pax. I can't remember how much over weight we were but it was at least a few tons.

I only have limited experience with 737-4/500 and A32S. On the 737, OWL was forbidden, unless commander decides otherwise as Capt. Claret describes. On the A320 the situation is the same, but like an icing on a cake, QRH contains an OWL checklist, OW circle-to-land with one engine inoperative data and pilots are trained to do so. That may be course specific The important thing is to make an entry into the tech log because inspection is required. I have been told that unless the touchdown vertical speed was above 460 ft/min (which is rather heavy landing, but maybe my memory fails me) visual inspection will suffice.

At first, I was stunned how "good" the A320 is compared to 737. But if you give it a deeper thought both are certified along the same rules so structural margins could be the same. Maybe all the difference is the manufacturer's decision to equip pilots with a tool to deal with such non-standard situation.

Also, at MTOW and quick landing with 500 kg less A320 comes 16-19% owerweight. I would guess that other small jets are about the same and hence fuel jettisonning is not installed. I wonder what would be the ratio for the widebodies. Is it at all possible to land a 747/340 at MTOW -2t ?

Yes - manual landing, as autoland not recommended above max. landing weight.

I am with Capt. Claret but would upgrade the uncontrollable fire to ANY FIRE. What is "uncontrollable". Do controllable fires put out less toxic fumes/smoke or do less destruction than an uncontroled fire. I ain't hanging round to find out.

Maui

re from captain87
 

I think that an overweight landing is severely dangerous in every sitation on every aircraft ... A pilot can perfectly read on the FCOM (Flight Crew Operations Manual) that the fuel dumping is always recommended until a normal landing weight has been established.
I have studied for A320 type-rating (oral only): for the A319/A320/A321 you can find written on FCOM that the overweight landing is inhibited ... but I personally believe that it cannot be performed on other aircrafts otherwise.
If the a/c manufacturers has fixed the limits, this means that their cannot be ovveriden ...
Regards !!!

As the chaps say above, if you need to do it then do! When you have a cabin fire etc you might as well chuck the manuals out of the window and get it on the deck, that is the priority...I have done 2, one after engine vibratrion and the other medical emergency. On both occasions there was merely an overweight landing inspection to do which takes a couple of hours tops. (NON EVENT). Its all about priorities guys not manuals and beancounters!!

re from captain87
 

Absolutely true !!!

I think the same. But unlikely the flight manuals state the contary: The overweight landing is severely forbidden. Do not attempt to accomplish a landing at weight greater than the MLW (Maximum Landing Weight) ...
I think that in-flight there is no time to think, the only true procedure is to make what you retain true !!! ... obviously into the safety limits !!!

Not strictly true, boeing produce a checklist for overweight landing (certainly on 757/767). Aircraft are certified to land at max TAKE OFF weight with rate of descent of 300fpm (from the dark depths of memory)...obviously you do your best to reduce weight towards max landing weight (dump fuel) but not at the cost of anyones life, for example in medical emergency situation....an overweight landing check will be required subsequently.

Yes you run the risk of tyre burst, cooking brakes etc but thats what long runways and reversers are for!!

cheers

Maybe one of the TP/FTE's on here can fill us in on UK certification limits??

re from captain87
 

Oh yes,
I was refferring to the A320 Family,
I have only a general knowledge of the 767 ...
I do not absolutely put in discussion the existence of the overweight checklists on 767 ... but I'd like to make one question:
Why the 767 is certified to perform an overweight landing and the A320 do not ?
... I think it's purely a question of manufacturers ... Boeing agrees and Airbus disagree etc ...

It's normal that one (FAA or EASA certified) aircraft have to be able to land in every condition, but there is no necessity to say: Aircraft not certified to accomplish an overweight landing ... as the flight manuals state ...
This depends from the situations, it is obvious that if it is possible, the fuel dumping have to be accomplished by the flight crew ...
Question of good sense ...
Regard !

Yeah capt, i have no idea about A320 family, sorry.
My understanding was that it was a UK CAA certification for any aircraft to come onto the UK reg to be able to do this without any untoward problems? Not 100% sure....maybe the TP's will interject!?

cheers

re from captain87
 

No problems !!!
Unfortunately the aeronautic is a complicated matter.
One aircraft differs from another and so the pilots ...
The pilots with specific type-ratings are machines programmed to operate
with the certified type only. So it's impossible to find a good compromise ...
I'm an ATPL Student who is studying for A320 CBT since 6 mounths ...
so I have to apologyze with you for having discussed about a stupid topic like the "overweight landing" with 2 different aircrafts !

Regards from captain87

No problemo its a big topic - quite an interesting one for you when it comes to your command training in a few years.

re from captain87
 

I thank you for your consideration.
I've 19 years ... too young to become captain ? ... what luck !!! ?!

Good bye !!!

“I think that an overweight landing is severely dangerous in every situation on every aircraft.”

Those who think like this may find that they have mistaken beliefs, particularly when the subject is discussed with the manufacturers. Most aircraft type certifications will clear an overweight landing for a touchdown at or less than 6 ft/sec. Although many design safety margins may compromised e.g. wind, drift, brake energy etc, the manoeuvre is perfectly safe; aircraft continue to follow aerodynamic and mechanical laws. The Captains judgement of safety (safety of life) can override AFM limitations – these situations, operations beyond a limit, should trigger additional thoughts about any change of procedure or other mitigating action.
Just remember that the aircraft is heavy, it will involve higher speed and higher energy (V*2). Opportunities for error arise in judging the higher speed and approach path – you may experience an inbuilt bias to slow down to make the landing scene appear normal. The flare manoeuvre, unless specified, should be the same as normal. Remember that the aircraft has taken off at this or a similar weight – the approach and landing capability does not fall off a cliff edge at MLW.

My Information concerning this topic (A320):

- 120 ft/min considered as normal touchdown rate
- 360 ft/min certified up to MTOW (that is the already mentioned 6 ft/sec)
- 600 ft/min certified up to MLW

Extensive inspections required for overweight landings with 360 ft/min or greater.

Beyond that, everything was said already in the posts above (reasons, risks & benefits etc).

re da captain87
 

For A320 the MLW is 61.000 Kg (134.480 lbs) ... with the following attenuating:

"In exceptional cases (in flight turn back or diversion), an immediate landing at weight above maximum landing weight is permitted, provided the pilots follows the overweight landing procedure"

But I'd like to remind that I have said that the overweight landing is always not recommended, and I haven't said that it's impossible ...

... Airbus write in the procedures to consider the use of the overweight checklists in extreme situations only !

Regards

I have got the same data for the 737, I do not remember if it is a JAR requirement rather than specific data for each airplane.

re from captain87
 

I think isn't important the rate of descent to accomplish an overweight landing. The only important thing is when a pilot have to perform it ???

good afternoon !

Captain87,

no one is going to perform an overweight landing if it is not strictly necessary. If you get into a critical condition which does not revert into an out of critical condition, you have no choice : you MUST land as soon as possible. Critical conditions are part of another subject that has already been covered a few posts earlier. A properly executed overweight landing will cause no big damages to the airplane.

Well if you perform a hard overweight landing you probably will need some of the fire brigade waiting for you beside the runway. So I would carefully manage my rate of descent.

re from captain87
 

For I-2021

I'd like to remind that each kind of failure, situation or condition require an immediate action ... but this action is specified by the checklists !
The impulsiveness is not tollerated aboard an airliner ... if there is a way to revert from an immeditely overweight landing to a delayed normal diversion with safe landing, this procedure MUST always be used !
Follow the checklists and you'll fly safely !

My understanding of the regulations is that if the manufacturer does not or can not certify that the aircraft can land above MLW with a RoD less than 360 ft/min without structural damage, then a fuel jettisoning system must be installed. Hence, the very large long haul machinery needs to jettison because at MTOW they are substantially above their MLW.

By that logic, if the aircraft has a MTOW greater than MLW and it does not have a fuel jettisoning system, then landings are safe up to MTOW provided the RoD is controlled.

As many have said, you will not burst into flames immediately on impact if you are above MLW. Even if you land heavily while at MTOW, you will cause structural damage, but that does not mean that the wings fall off or the wheels go bouncing across the perimeter road and over the fence. I would much rather risk a technically written off fuselage than hang around in a hold on one engine for an hour or two while I burn off fuel. I would be inclined to add any failure, other than trivial ones to my list of failures that would warrant an overweight return.

Give me hydraulic trouble, electrical problems, engine problems, or of course the smoke or fire and I'll go back heavy every time.

captain87.

You're 19 years old. I believe you haven't sat in an airline cockpit before? I appreciate you being interrested and motivated, but please trust the statements given here (a compilation of the posts):

- An overweight landing is performed as soon as it gives the same or higher degree of safety than the continuation of the flight. (My operators OM-A)

- A320s are certified to land with a rate of up to 360 ft/min with MTOW!

- the rate of descent is important.

- Airbus does not say, that overweight landings are dangerous, because they aren't!

- Executed with a smooth touchdown, a long runway, not a lot of brakes and max reverse: no problem! One inspection, one signature from the mechanic - and you're back in the air.

Regards

re from captain87
 

The rate of descent is important for pressurization issues only , but it's relevant also for other issues: stopping the aircraft on the runway, brakes efficiency, gear strut damage etc. ... but this is another topic ...
A practical example:
The A320 QRH state that it's not recommended to land with a residual cabin differential pressure ... but if we have to manage a SYS 1 +2 failure and at the same time we are above the MLW (just after takeoff) ... what procedures are required ? ... it' all written in the QRH ... no hazardous procedures necessary !!!
I know that it's very simple to speak from a chair ... but this is our job !

re from captain87
 

I excuse with Charlie !
Unfortunately the humilty isn't my point of strenght ...
I have only 19 years, but what I say is originated from what I've studied
through the CBT, the FCOM's, the QRH etc.
Obviuosly I'm too young for operating aboard an A320, I hope to do it in a next future ...
I enjoy to share my aeronautical belief ...

True most of the time.

It is the same with women.

I would prefer to make an overweight landing but since it is better to land safely below MLW, then I will do it !

I will !

No checklist for that...

Ciao.

re from captain87
 

Ahhhhhhhhhhhhhhhhhhh
Thank you !!! I've discovered a way for my character:
the humilty checklists !!!
Caution: Operate only before flight !!!

It's a very good gimmik !!!
Ciao

B737-NG's....Manufacturer has CERTIFIED the airplane to do a MTOW minus 5% landing weight landing with a maximum of 1.3g's to be cleared by their technical team with a visual(al biet a thorough one...!!) post flight.
Cheers now and enjoy those days when u get to do one........they're the only ones worth flying for....!!:ok:
BD

FAR 25.1001 (If i remember correctly) Fuel Jettison System: states that an aircraft must be able to achieve the required approach/landing climb gradients within 15 minutes of takeoff.
All of our landing field length limit charts have weights much greater than the MTOW.
We stipulate that overweight landings are not permitted for commercial reasons, in all other cases crew must assess if they can satisfy the field length limit weights and approach/landing climb limits and follow the appropriate overweight landing checklist.



Mutt

I've had to do an overweight landing on a 757-300 about 5 months ago.We air returned to SJU because of a reported vibration from one of the girls in the back. We were 20,000 lbs over MLW and no dump capability. My first officer did a superb job of landing on speed on target without an excessive rate of descent. We pulled back out of the gate about an hour and a half later after an inspection and headed home. It didn't seem like a big deal.(Except the paperwork of course!)

must... resist.... joke...

re from captain87
 

For my point of view an overweight landing have to be considered for medical and fire emergencies only. If we lose one engine just after takeoff, the procedure (on the A320) states that it's strictly necessary to dump as fuel is possible until reaching the MLW or below.
It's unacceptable that we perform an overweight landing if there are other ways to solve the problem in question.
On the A320 i.e., if one engine fails just after takeoff, the procedures say to mantain V2 +10 until reaching A/H-R/H (acceleration altitude/reduction altitude).Then the climb may be continued with a minum climb gradient of 300 ft/m. Then following, if applicable, the EO (engine out) SID. - LAND ASAP
The fuel dumping is mandatory !!! becouse there is time to do it .
In addition to this each other situation (emergency after takeoff) can be perfectly executed with fuel dumping (except medical or fire).
A question: are there other situations who give priority for landing ASAP without considering the MLW limits ? ... I think no ...
DO IT EVERY TIME YOU CAN !

Couldn't you have just confiscated her batteries? :E

You are quoting a lot of stuff from the manuals, but as far as I know, the A-320 is not capable of dumping fuel !?!

re from captain87
 

No in fact, you're perfectly right !
I said a big fake !!!!
Airbus has forgotten to program it ...
Sorry ....

re from captain87
 

The true procedure for A320 in case of overweight landing are the following:

OVERWEIGHT LANDING

- LDG CONF ...................... DETERMINE
- LDG DIST ...................... CHECK
- PACK 1 and 2 ................. OFF or supplied by APU

In final stages of approach

- TARGET SPEED .................. VLS

At main landing gear touchdown

- REVERSE THRUST ........... USE MAX AVALIABLE

After nose wheel touchdown

- BRAKES ........................ APPLY AS NECESSARY

Landing complete

BRAKE FANS ....................... ON

Sorry for having said a fake before ! I was thinking at the same time to A320 and 767.
Unfortunately my absent-mindedness is a typical characteristic in some cases ...

I am somewhat concerned by how "serious" an overweight landing is considered above...

As far as I know, any 2 engine aircraft will require effectively "Land ASAP", and at nearest suitable airfiield, after (even partial) loss of 1 engine - over MLW or not. Maybe there are exceptions... but for 757/767, A319/320/321 in my company this is the case. Some 767s (not all) can dump fuel, but only from Centre Tank, and there was no requirement to get to MLW before landing, or even dump to max extent possible. In a 3+ Engine aircraft, I can see MLW being adhered to for a simple (single) EO.

NB sometimes the MLW is commercial - our MLW limit has changed for the A319 a few times recently. It is strange to need to do the "overweight landing checklist" (and engineer's checks) one day, but don't need to do the next day same weight / same aircraft :ugh:

My main concern with overweight lanidng is the stopping / GA performance. The RoD / Inspection requirements are engineers' problems, not mine ;)

C87 are you studying A320 on Wilco manuals? :E

Regards