PPRuNe Forums - View Single Post - New (2010) Stall Recovery's @ high altitudes
Old 9th August 2010 | 07:41
  #140 (permalink)  
PBL
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Joined: Sep 2000
Posts: 965
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From: Bielefeld, Germany
BOAC,

I am not sure what you are quibbling about. Of course I have selectively quoted - all quoting is selective.

The FOG in 2.2.8 is addressing loss of lateral stability (wing drop) and says rudder use to arrest it is not recommended and may be expressly forbidden. As far as I know, wing drop is most likely to occur during progress into a stall, so, apparently unlike you, I read this comment as being highly relevant to stall.

In Section 3 they talk generally about unusual attitude recovery, and the advice is intended to be clear: destall the wing before anything else.

When talking in Section 3 of unusual attitudes with decreasing AS at high angles of bank in the case in which ailerons and spoilers are ineffective, they do suggest to try a little rudder to induce a roll, and guard this advice quite specifically. Well, of course they say that - what other option do you have if all other roll control is demonstrably ineffective and you need to roll?

I read them as saying: priority number one, destall the wing; if a wing drops, don't use rudder to arrest it, unless you get into high angles of bank while still stalled, and need to roll to drop the nose, in which case a little rudder, briefly, may be required to induce a roll.

Given the propensity of some on this forum to read a quote or an interpretation as the opinion of the writer, rather than of those quoted, let me emphasise that in the case of discrepant readings it is up to the FOG to clarify what they mean, not me. I am just reading what they wrote. But if one wants to be sure what they meant, I do know a couple of people in the group so can ask directly if it's something major.

I do note that in the three places in which they mention rudder use, in only one of them do they mention the possibility of structural damage in injudicious use of rudder. I guess this is because they are primarily talking about very low airspeed situations.

I also note that this is not the only document concerning upset recovery. A U.S. working group also prepared the upset recovery aid, a fairly large document, between 2004 and 2008. It may be found on the FAA WWW site: the Upset Recovery Training Aid, as well as by the FSF.

PBL

Last edited by PBL; 9th August 2010 at 07:51.
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