During initial training I was told stories about pilots that would extend the flaps to 2 degrees at altitude to increase fuel efficiency, but to do that you have to pull a couple circuit breakers to disable the leading edge devices (LED's) which are limited by Boeing from being extended above 20,000 feet. When you do this stunt, you are risking air pressure getting up under the spoilers and causing them to float - thus negating what you're trying to accomplish. Also, the elevator trim is controlled by the autopilot at altitude . . . if you try to trim the nose up the autopilot will kick itself off. I could see where an unbriefed pilot resetting the LED circuit breakers at altitude could cause really hideous problems. . . but I highly doubt the Split-S (with 2 of 4??) maneuver . . . more likely a 7.5 on their Straight Flight Out followed by a Zero'd flight due to the LED's departing the aircraft.<br>
<br>Besides, the flaps and trim have no effect on the CG of the airplane. . . it is a function of how the plane is loaded and the current fuel load - which by the way moves the CG forward during flight unless your S/O does something really, really wrong on the fuel panel. My company is currently trying to load the airplanes with an aft CG for fuel efficiency.<br>
<br>Now, back to the original subject. . . will a swept wing commercial transport aircraft perform a proper snap roll? . . . . My vote is "only once". . .<br><br><div class="gmail_quote">On Tue, Jul 1, 2008 at 6:03 PM, Gerald Gallagher <<a href="mailto:ggall@bellsouth.net">ggall@bellsouth.net</a>> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">I was a pilot with TWA & knew the captain that is accused of this, also a<br>
TWA Pilot. To this day he denies this ever happened & so do the 2 other crew<br>
members that were flying that 727. The loss of altitude was, according to<br>
the three crewmembers aboard was clear air turbulence. I believe the pilot,<br>
but I am prejudice.<br>
<br>
Jerry Gallagher<br>
<br>
<br>
<br>
-----Original Message-----<br>
From: <a href="mailto:nsrca-discussion-bounces@lists.nsrca.org">nsrca-discussion-bounces@lists.nsrca.org</a><br>
[mailto:<a href="mailto:nsrca-discussion-bounces@lists.nsrca.org">nsrca-discussion-bounces@lists.nsrca.org</a>] On Behalf Of<br>
<a href="mailto:rcmaster199@aol.com">rcmaster199@aol.com</a><br>
Sent: Tuesday, July 01, 2008 5:47 PM<br>
To: <a href="mailto:nsrca-discussion@lists.nsrca.org">nsrca-discussion@lists.nsrca.org</a><br>
Subject: Re: [NSRCA-discussion] 747 Snap Entry?<br>
<br>
<br>
A few of us were discussing just such an occurence recently which<br>
apparently happened by accident and darned near crashed the plane. Dean<br>
remembered the details which went something like this:<br>
<br>
The pilot of the 727 about 20 years ago had the plane trimmed as far<br>
aft as possible and had inputed a bit of flap to use fuel most<br>
efficiently. The co-pilot, soon after returning from a visit to the<br>
loo, saw the trimmed flap and flipped the switch to return the flap to<br>
neutral. This action immediately made the plane too tail heavy which<br>
made the plane do a pretty violent half snap to inverted. The pilot<br>
lost close to 25k feet pulling the plane out of the dive, which he did<br>
successfully but not before deploying the gear to slow the crate down.<br>
That had to be some kind of experience<br>
<br>
Legend has it that the pilot then went straight to loo himself to<br>
change his britches (G)<br>
<br>
Matt<br>
<br>
-----Original Message-----<br>
From: Koenig, Tom <<a href="mailto:Tom.Koenig@actewagl.com.au">Tom.Koenig@actewagl.com.au</a>><br>
To: General pattern discussion <<a href="mailto:nsrca-discussion@lists.nsrca.org">nsrca-discussion@lists.nsrca.org</a>><br>
Sent: Mon, 30 Jun 2008 10:25 pm<br>
Subject: Re: [NSRCA-discussion] 747 Snap Entry?<br>
<br>
Hey John,<br>
<br>
Out of interest.....has anyone ever attempted a snap in an airliner???<br>
<br>
I have heard of a captain doing a slow roll in a 747....but a snap? Is it<br>
possible?? What does a simulator do when pushed to such limits ( I know a<br>
simulator cant snap BTW...well, I assume any way LOL!!)<br>
<br>
Tom<br>
<br>
-----Original Message-----<br>
From: <a href="mailto:nsrca-discussion-bounces@lists.nsrca.org">nsrca-discussion-bounces@lists.nsrca.org</a><br>
[mailto:<a href="mailto:nsrca-discussion-bounces@lists.nsrca.org">nsrca-discussion-bounces@lists.nsrca.org</a>] On Behalf Of John Gayer<br>
Sent: Tuesday, 1 July 2008 11:42 AM<br>
To: General pattern discussion<br>
Subject: Re: [NSRCA-discussion] Snap Entry<br>
<br>
Actually a snap can occur without any aileron input...but I challenge anyone<br>
to show a pattern ship doing a snap roll on a 45 degree downline without<br>
ailerons.<br>
<br>
The approach snap can occur with only the use of elevator and it involves<br>
one wing panel stalling before the other. Try an approach with crossed<br>
controls(aileron/rudder with some power. pull the nose up gradually and see<br>
which wing drops. It will be the wing with the aileron trailing edge down.<br>
This is contrary to what we see in a pattern snap roll which always snaps in<br>
the direction of the aileron deflection thus indicating the lack of any<br>
stalled condition<br>
<br>
John<br>
<br>
<a href="mailto:seefo@san.rr.com">seefo@san.rr.com</a> wrote:<br>
<br>
>Just to stir the pot a little further..<br>
><br>
>I'm not sure a contemporary pattern plane can generate enough pitch<br>
rate to reach critical angle of attack and properly perform a snap roll. I<br>
think it's far more likely that we're seeing nothing but a heavily yawed<br>
aileron roll, with the pitch break only being shown to judges to convince<br>
them there is actually a stall happening, when in fact there is not.<br>
><br>
>If a snap cannot occur using ONLY elevator and rudder, then the wing is<br>
not stalling. Aileron inputs into a snap actually inhibit flow separation,<br>
as the inboard wing angle of attack is drastically reduced, and the outboard<br>
wing AoA is drastically increased.<br>
><br>
>But since there is no way to actually determine what is happening<br>
aerodynamically on an F3A airplane, the best a pilot can do is fly the<br>
airplane to what the judges expect to see based upon the rules. It really<br>
doesn't matter what the control inputs are if the airplane LOOKS like it's<br>
doing the right maneuver.<br>
>_______________________________________________<br>
>NSRCA-discussion mailing list<br>
><a href="mailto:NSRCA-discussion@lists.nsrca.org">NSRCA-discussion@lists.nsrca.org</a><br>
><a href="http://lists.nsrca.org/mailman/listinfo/nsrca-discussion" target="_blank">http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</a><br>
><br>
><br>
><br>
_______________________________________________<br>
NSRCA-discussion mailing list<br>
<a href="mailto:NSRCA-discussion@lists.nsrca.org">NSRCA-discussion@lists.nsrca.org</a><br>
<a href="http://lists.nsrca.org/mailman/listinfo/nsrca-discussion" target="_blank">http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</a><br>
_______________________________________________<br>
NSRCA-discussion mailing list<br>
<a href="mailto:NSRCA-discussion@lists.nsrca.org">NSRCA-discussion@lists.nsrca.org</a><br>
<a href="http://lists.nsrca.org/mailman/listinfo/nsrca-discussion" target="_blank">http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</a><br>
<br>
<br>
_______________________________________________<br>
NSRCA-discussion mailing list<br>
<a href="mailto:NSRCA-discussion@lists.nsrca.org">NSRCA-discussion@lists.nsrca.org</a><br>
<a href="http://lists.nsrca.org/mailman/listinfo/nsrca-discussion" target="_blank">http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</a><br>
<br>
_______________________________________________<br>
NSRCA-discussion mailing list<br>
<a href="mailto:NSRCA-discussion@lists.nsrca.org">NSRCA-discussion@lists.nsrca.org</a><br>
<a href="http://lists.nsrca.org/mailman/listinfo/nsrca-discussion" target="_blank">http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</a><br>
</blockquote></div><br><br clear="all"><br>-- <br><br>Keith Hoard<br>Collierville, TN<br><a href="mailto:khoard@gmail.com">khoard@gmail.com</a><br><br>