A hypothetical situation, and a doubt

Greg F. wrote:

Remember, you are not using 100% power for TOGA, and you have FADEC which will
compensate immediately.

Not using 100% power for takeoff? I don't fly jets but that sounds odd
to me. What T/O power setting are you suggesting is used in a 747? Is
it whatever the engine controller will allow when the power levers are
firewalled?

Also, the FADEC controller will not compensate in the way you think.
IIRC it adjusts fuel flow rate to maintain temps, EPRs & rpm parameters
to stay within limits. It's there to efficiently manage power and keep
a ham-fisted pilot from smoking the engine's hot section. I doubt it
will have any effect in a engine-out go around as it won't allow the
engine to exceed parameters.

Dave S wrote:
Scuse me.. I'm not a multi driver... let alone a 747 pilot...

but if I lost 25 percent of my power I think that I would notice some
performance loss...



I am a multi pilot but I've never flown anything bigger than a cabin class twin.
So I asked my father, who flew various large aircraft for the USAF from 1943 to
1967. He wrote:

"There are just two issues involved in losing an engine in a four engine
aircraft.....thrust and control. The C-54 was designed to function almost
completely normally on three engines. I don't remember the actual numbers,
but assuming normal cruise to be 160 mph on four, you might lose as much as
10 mph if one fan went out. IOW, the impact on performance would have been
negligible.

In terms of lateral control, especially near or on the ground, loss of an
inboard would have been preferable to loss of an outboard.

When you got into loss of two engines, it got a lot more sticky if they were
both the same side. If you lost one on each side, it wouldn't make hardly
any difference whether one was inboard and the other outboard or vice versa
as long as you remembered that your operating outboard engine would have a
tendency to want to turn the plane towards the inboard. Apart from that,
you were running essentially a twin with not too much margin of error left
for you."

I assumed if you lost both engines on one side, you'd be in the same situation
as if a twin lost one engine.... you would have an immediate and unmistakable
change in your flight situation requiring some sort of action. What I didn't
know was how much stronger the reaction from a four engined aircraft might be if
it lost an outboard vs an inboard engine.



--
Mortimer Schnerd, RN

VE

On 2006-04-08, Greg Farris wrote:
[one engine loss]
done by the book. In a 747 you should hardly notice any performance loss.

Depends how heavy the B747 is. There is an 'I Learned about flying from
that' article in one of the books published by Flying magazine where a
B747 lost one engine due to a compressor stall on takeoff out of London
Gatwick. They were at maximum takeoff weight when it happened. They
almost rolled it into a ball - it took them a couple of miles just to
get out of ground effect (one of the passengers recalls looking through
the windows of a nice Georgean mansion as they roared past, with the
trees waving in their wake).

--
Dylan Smith, Port St Mary, Isle of Man
Flying: http://www.dylansmith.net
Oolite-Linux: an Elite tribute: http://oolite-linux.berlios.de
Frontier Elite Universe: http://www.alioth.net

Bob Moore wrote:

Of course you can go-around on one engine. Transport category a/c
are required by regulation to be able to do that.
After all....the airplane is able to continue the takeoff after
an engine failure while still on the runway and past the V1 speed,
it stands to reason that if already airborne and at a speed higher
than V1, it can continue flying.
:-) :-)

Bob Moore

I get it now.
And nicely put, buddy, as usual
I thought you were still snowed under with computer work, thus Option 2


Ramapriya

Gee, now I'm not so worried about just flying behind a single fan!

smackey
C172 pilot