Re: Question: Fuel Dumping

Date:         21 Jan 97 01:32:28 
From:         Pete Finlay <pete@meads.demon.co.uk>
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In message <5bq7na$vh@news.indigo.ie>, ifly <ifly@indigo.ie> writes
>The previous poster was correct.

Not 100%.

>The main reason your landing weight is
>restricted in most airliners is your go around climb profile.

That may be the case on smaller aircraft where the maximum landing
weight is a higher percentage of the maximum take off weight, but the
go-around climb profile of a 747 which is below max. landing weight is
an awful  lot better than the T.O. profile at max. T.O. weight.

The maximum T.O. weight for our 747-236 aircraft is 372 tonnes, with a
normal flap setting of 20 degrees.

Max landing weight is 285 tonnes, with a normal flap setting on the go-
around of 20 degrees (although the initial flap setting on the go-around
may be 25 degrees i.e. landing flap, this is pulled back to 20 degrees
early on in the go-around).

AFAIK, the restriction for maximum landing weight for the 747, as
decreed by Boeing, is purely structural. I can't remember ever coming
across a case flying Boeing 707, DC-10, or Boeing 747 where the maximum
landing weight wasn't structural. I don't think I've ever had a
performance landing weight below max. landing weight. Maybe Bogota on a
hot day with an engine out.

>Having said that, sometimes the restriction is structural, and other
>times it`s based on runway length, so just as in takepoff RTOW`s there`s
>a number of landing weight restrictions.

That may be the case on some types of aircraft, but not on the ones I've
flown.

>If I had a flap/slat problem, I`d just pick a longer runway!

Wouldn't we all. It is possible to pick a longer runway in Europe, or
the States, but where we fly to, we very rarely have the option of going
for a longer runway or different airfield :{

--
Pete Finlay
pete@meads.demon.co.uk
Boeing 747 Senior Flight Engineer