Re: Ethiopian crash, Gimli, RAT and FLAPS

Date:         06 Jan 97 01:41:44 
From:         lstone@interserve.com (Larry Stone)
Organization: InterServe Communications, Inc.
References:   1 2
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In article <airliners.1997.115@ohare.Chicago.COM>, kls@ohare.Chicago.COM
(Karl Swartz) wrote:

>>I've ... NOT yet acquired any certainty about RAT alone being or not
>>able to deploy flaps or/and slats, them being essential to a safe landing!
>...
>>The 767 of Air Canada had a huge amount of time running on
>>the RAT to be able to deploy them, even slowly.
>
>Flaps add a *lot* of drag.  If you are gliding and aren't sure you'll
>be able to make it to an airport, deploying the flaps long before you
>actually get to the airport is the last thing you'd want to do.

To add to what Karl said, flaps are *NOT* essential to a safe landing
although they make it easier. In the landing configuration, flaps add
mostly drag (takeoffs, when done with flaps, are with much less flaps -
adding lift but not so much drag - for the light planes I fly, take-offs
are normally flap less but for some conditions, you would use 10 to 25
degrees of flap. Landings are done with full flaps - usually 40 degrees).

The two advantages of flaps for landing is a lower approach speed and a
steeper approach angle. The lower approach speed of course translates to
less runway used. In a "dead-stick" situation, flaps are typically not
added until landing is assured.

I have landed every model in which I have been checked out at least once
(for practice) without flaps. Not difficult at all and improves
controllability in high cross-winds.

--
-- Larry Stone --- lstone@interserve.com
   http://www.interserve.com/~lstone/
   Belmont, CA, USA
   My opinions, not United's.