A flat tire...

[Crusader]

Most combat aircraft have a high enough maximum landing weight that they can keep the ordnance under normal conditions. (Jettisoning fuel is usually enough to get under max landing weight.)

These days the only time ordnance is jettisoned prior to landing is if there is a significant chance of mishap on landing, ie battle damage. Even naval aircraft regularly recover onboard carriers with unexpended ordnance.

I stand corrected. I double-checked the reports of NATO bombs in the Adriatic, and they were indeed not routinely jettisoned (as I had mistakenly believed), but only when a plane was experiencing mechanical difficulties.

Now back to the original thread.

[Ron Engels]

....As you know, typically after an incident such as this recommendations for future prevention are made. Has your airline already done this and if so, could you share the recommendations with us?
......
Ron

Could be that there will be, but as you will undoubtedly know it's unfortunately not unknown for debris and junk to find it's way on to a platform.
Should there be any recommendations, I'll let you know.

[Ron Engels]

Thanks for the excellent post Pierre.
If I have the time, and it's physically possible I always try to go and have a look for myself, when the AMT's are working on my aircraft.
It's good to know that there are well trained, responsible and hard working men (why are there no woman come to think of it?) taking care of our aircraft.

[Ron Engels]

I have always wondered whether it is substantially more difficult to land a cargo plane as its landing weight with a full cargo load (a whopping 90 tons in the case of the MD11, if I am not mistaken) probably is a bit higher than a passenger plane of the same type, and I assume there is also more stress on the wheels when the plane touches down on the runway.


Any insights from pilots/engineers?

First of all, a cargo plain need not be any heavier then it's passenger counterpart. The basic structure of the aircraft, wing, gears etc, are all identical, and that limits the maximum structural weights.
But passenger aircraft are full of seats, toilets, pantries, catering, emergency equipment, entertainment equipment etc. That means that the weight of a passenger aircraft without any payload is a lot higher then that of a cargo plane, that really only needs a floor with fittings to hold the pallets. Therefor, if the maximum total weight is the same, you can carry much more payload in a cargo plane, before you reach that maximum weight.
Secondly, if an aircraft gets heavier, it doesn't necessarily gets harder to land. I always felt that a 747 (I only flew the 'classic') was easier to land when it was heavy, then when it was light (relatively speaking ).
The B777 is fly by wire, and you hardly notice any difference at all. The computers correct for weight, and load distribution, and make the flight controls respond in exactly the same manner. Not to long ago I needed to make an overweight landing (almost 50.000kg over) and it felt just like it always did.

While the wheels and gear will probably be under the greatest stress at touchdown, the tires (like Pierre pointed out) are under the biggest stress at high weights, and therefor during departure and take-off. Tires can heat up significantly from taxiing alone. The high speed aborted take-off is most critical. The already warm tires, have to put up with all the heat generated by the brakes, often resulting in needing to change most wheels.

[Crusader]

Very interesting, Ron - thanks for the info!

[stockae92]

Oh, and should you wonder what our maintenance technician that is changing the wheel is wearing? It's a Seiko 'monster' i believe they call them. Turned out he was a Panerai aficionado. For obvious reasons he didn't wear those to work.

to be a Panerai aficionado, they must paid him well .. lol

btw, those are interesting, we don't get to see that at all. thanks for posting

[Crusader]

While the wheels and gear will probably be under the greatest stress at touchdown, the tires (like Pierre pointed out) are under the biggest stress at high weights, and therefor during departure and take-off. Tires can heat up significantly from taxiing alone. The high speed aborted take-off is most critical. The already warm tires, have to put up with all the heat generated by the brakes, often resulting in needing to change most wheels.

I think this thread serves well to demonstrate the well-founded concern that pilots and engineers devote to the tires ... to be honest, I never thought that mere taxiing and turning could significantly affect the tires. :oops:

May I ask what the margin of safety is concerning the wheels/tires, i.e. could a plane lose half of its tires and still land safely (assuming a fairly even distribution of the blown tires among the landing gears, obviously), or would, say one or two flats out of six wheels in a gear already present a major danger?

[Strela]

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[snorkeler]

Very cool pixs! I love the carbon fiber disc brakes, esp the mongo calipers.

What type/model plane are the pix of?

How is the jack powered?

How many kg does the jack hold when the wheel is being removed?

[pegase747]

Very cool pixs! I love the carbon fiber disc brakes, esp the mongo calipers.

What type/model plane are the pix of?

How is the jack powered?

How many kg does the jack hold when the wheel is being removed?

Hi Snorkeler,

The model is a Boeing 777-200ER, an excellent and very successfull aircraft, in my opinion...

The jack is hydraulic powered, and usually the pump is actuated by air or manually.

The hydraulic jack used for lifting the plane is normally rated at 95 tons, or 216.000lbs.

Hope thta nswers you questions..

Pierre