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DAVELEIKAM(at)wi.rr.com
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 Posted: Wed Jun 06, 2007 8:01 pm Post subject: Runaway trim |
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A few days ago a Citation jet carrying a crew of two and 4 medical personnel including organ transplant doctors, went down in Lake Michigan just off shore from Milwaukee, WI shortly after takeoff. The pilot declared an emergency due to severe control problems and was cleared to return to MKE. No survivors. First my condolences to the families and friends. Next, preliminary reports are that the crash may have been due to "Runaway trim." Our RV-10s have electric trim. Should we or has anyone installed a trim power disconnect of some sort? I realize that the forces to overcome full trim on the 10 are not as great as a Citation, but would this be prudent? After Attending Bob Nuckolls seminar and hearing his reasons for not installing circuit breakers which I generally agree with, would this be a reason for a pullable breaker on this circuit? What do you guys and gals think? Mr. Nuckolls, how about your thoughts?
Dave Leikam
40496 RV-10
QB Wings
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ron.mcgann(at)baesystems.
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| Posted: Wed Jun 06, 2007 8:14 pm Post subject: Runaway trim |
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A very tragic accident by all accounts.
I have almost all electric circuits through a Main Bus-E-Bus-Battery Bus fuse system ala Nuckolls. I made sure that ALL flight controls (trim, flaps, AP etc) are available on breakers with easy access for quick power removal.
cheers,
Ron
187 finishing (endlessly)
[quote] From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Dave Leikam
Sent: Thursday, 7 June 2007 2:31 PM
To: RV-10 matronics; aeroelectric-list(at)matronics.com
Subject: RV10-List: Runaway trim
A few days ago a Citation jet carrying a crew of two and 4 medical personnel including organ transplant doctors, went down in Lake Michigan just off shore from Milwaukee, WI shortly after takeoff. The pilot declared an emergency due to severe control problems and was cleared to return to MKE. No survivors. First my condolences to the families and friends. Next, preliminary reports are that the crash may have been due to "Runaway trim." Our RV-10s have electric trim. Should we or has anyone installed a trim power disconnect of some sort? I realize that the forces to overcome full trim on the 10 are not as great as a Citation, but would this be prudent? After Attending Bob Nuckolls seminar and hearing his reasons for not installing circuit breakers which I generally agree with, would this be a reason for a pullable breaker on this circuit? What do you guys and gals think? Mr. Nuckolls, how about your thoughts?
Dave Leikam
40496 RV-10
QB Wings
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Tim Olson
Joined: 25 Jan 2007
Posts: 2878
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| Posted: Wed Jun 06, 2007 8:36 pm Post subject: Runaway trim |
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Absolutely, 100%, if something has the power to control your plane,
put it on a pullable or switchable breaker. Flaps, Trim, AP, and
things like that all deserve a pullable breaker or breaker/switch.
Additionally, it's nice to have breakers that are pullable on
many of your avionics so you can power them off separately
from other things if needed. Save the fuses for the simple
things, like lights, fans, Wx systems, and all the added goodies.
I assure you, after flying for 225+ hours, a runaway trim event
in the RV-10 would have a high chance of doing something more
significant than just getting your attention....it would be
quite an event. Just gave a demo again Monday, and it's one
of the things I like to point out on the demo flights...what
a 1 second trim hold can do at 125+ kts. I haven't tried
more than a couple seconds, but I'm guessing you *may* be able
to pull the wings off the airplane with a significant (maybe 3
or 4 seconds), amount of runaway trim, if you were in cruise
and didn't catch it right away.
Dave, you're close enough, I've been meaning to get over
by you or have you come this way so you can get a ride.
I think you'd enjoy it.
Tim Olson - RV-10 N104CD - Flying
do not archive
Dave Leikam wrote:
| Quote: | A few days ago a Citation jet carrying a crew of two and 4 medical
personnel including organ transplant doctors, went down in Lake Michigan
just off shore from Milwaukee, WI shortly after takeoff. The pilot
declared an emergency due to severe control problems and was cleared to
return to MKE. No survivors. First my condolences to the families and
friends. Next, preliminary reports are that the crash may have been due
to "Runaway trim." Our RV-10s have electric trim. Should we or has
anyone installed a trim power disconnect of some sort? I realize that
the forces to overcome full trim on the 10 are not as great as a
Citation, but would this be prudent? After Attending Bob Nuckolls
seminar and hearing his reasons for not installing circuit breakers
which I generally agree with, would this be a reason for a pullable
breaker on this circuit? What do you guys and gals think? Mr.
Nuckolls, how about your thoughts?
Dave Leikam
40496 RV-10
QB Wings
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DAVELEIKAM(at)wi.rr.com
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| Posted: Thu Jun 07, 2007 4:01 am Post subject: Runaway trim |
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You don't have to twist my arm Tim!!!!!
I have been pretty busy as of late, but maybe around OSH time?
Thanks for the offer.
Dave Leikam
do not archive
---
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wcurtis(at)nerv10.com
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| Posted: Thu Jun 07, 2007 4:56 am Post subject: Runaway trim |
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There are only a few pull-able breakers on my panel, the rest of the devices are protected by fuses. The only pull-able breakers are the alternator, alternator field, flaps, autopilot and the pitch trim.
http://wcurtis.nerv10.com/91Panel/index.html
William
http://wcurtis.nerv10.com/
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jesse(at)saintaviation.co
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| Posted: Thu Jun 07, 2007 5:09 am Post subject: Runaway trim |
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I have heard 2 stories of how the -10 was inadvertently trimmed nose-up while the auto-pilot was engaged. The a-p held until it couldn’t hold anymore and then let go, putting the plane in an unusual attitude VERY quickly. The first one had the original servo and the second was with a high-torque servo, which was more dramatic. If the first pilot hadn’t mentioned his experience to the second pilot, he said he probably would have wet his pants, if not more. I put just about everything on a pullable breaker. Lights and fans and stuff like that, as Tim mentioned, can be on fuses, but having everything on breakers so you can shed load manually if you have an alternator failure, which DOES happen, is a good idea. Breakers cost about $16 each for the good Klixon ones, so 20 of them is going to cost just over $300, but probably less than $300 more than you would spend on the alternative. Just being able to shed loads when you are working on settings with the plane off is well worth it, IMHO.
One thing to keep in mind, though, is that if the trim gets into a situation like I mentioned above, pulling a breaker will NOT solve the problem, but will rather make it worse, because with no power you will not be able to get it back in trim. If your trim system goes bad, gets a short, has a bad switch or something like that so it starts trimming by itself, then you need to be able to get rid of the power. I also know of a case where a trim relay board went bad in one direction, so the plane was trimmed too far one way and they the pilot couldn’t get it back. The trip was only about 30 minutes, but he said his arm was absolutely exhausted by the time he got there. The -10 has a LOT of trim and is a big plane to pull against the trim on.
A word to the wise – when flying on a-p, disengage from time to time to trim the plane, even if you have the trim-sensing servo (which is fantastic, by the way) and especially if you have aileron and/or rudder trim. Having the plane trimmed right when you disengage for whatever reason, especially if it is on an IFR approach, is very important.
In short, you do want a way to kill the trim power quickly if you have “runaway trim”, but if you may have been pushing it accidentally, then cutting the power will make the problem worse. My suggestion in any case, cut the power and then assess the situation to see if it was you or some plane problem.
Jesse Saint
Saint Aviation, Inc.
jesse(at)saintaviation.com (jesse(at)saintaviation.com)
www.saintaviation.com
Cell: 352-427-0285
Fax: 815-377-3694
From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Dave Leikam
Sent: Thursday, June 07, 2007 1:01 AM
To: RV-10 matronics; aeroelectric-list(at)matronics.com
Subject: Runaway trim
A few days ago a Citation jet carrying a crew of two and 4 medical personnel including organ transplant doctors, went down in Lake Michigan just off shore from Milwaukee, WI shortly after takeoff. The pilot declared an emergency due to severe control problems and was cleared to return to MKE. No survivors. First my condolences to the families and friends. Next, preliminary reports are that the crash may have been due to "Runaway trim." Our RV-10s have electric trim. Should we or has anyone installed a trim power disconnect of some sort? I realize that the forces to overcome full trim on the 10 are not as great as a Citation, but would this be prudent? After Attending Bob Nuckolls seminar and hearing his reasons for not installing circuit breakers which I generally agree with, would this be a reason for a pullable breaker on this circuit? What do you guys and gals think? Mr. Nuckolls, how about your thoughts?
Dave Leikam
40496 RV-10
QB Wings
[quote] [b]
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planesmith(at)hotmail.com
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| Posted: Thu Jun 07, 2007 6:29 am Post subject: Runaway trim |
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Any idea what caused the trim run away in the RV10s? Was it accidental activation of stick mounted swtiches or some other problem?
On a side note, are people with Dynons using the Van's supplied trim and flap indicators or the Dynon option?
Vern Smith (#324 fuselage)
do not archive
| Quote: | From: jesse(at)saintaviation.com
To: rv10-list(at)matronics.com
Subject: RE: Runaway trim
Date: Thu, 7 Jun 2007 09:09:29 -0400
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I have heard 2 stories of how the -10 was inadvertently trimmed nose-up while the auto-pilot was engaged. The a-p held until it couldn’t hold anymore and then let go, putting the plane in an unusual attitude VERY quickly. The first one had the original servo and the second was with a high-torque servo, which was more dramatic. If the first pilot hadn’t mentioned his experience to the second pilot, he said he probably would have wet his pants, if not more. I put just about everything on a pullable breaker. Lights and fans and stuff like that, as Tim mentioned, can be on fuses, but having everything on breakers so you can shed load manually if you have an alternator failure, which DOES happen, is a good idea. Breakers cost about $16 each for the good Klixon ones, so 20 of them is going to cost just over $300, but probably less than $300 more than you would spend on the alternative. Just being able to shed loads when you are working on settings with the plane off is well worth it, IMHO.
Jesse Saint
Saint Aviation, Inc.
jesse(at)saintaviation.com (jesse(at)saintaviation.com)
www.saintaviation.com
Cell: 352-427-0285
Fax: 815-377-3694
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rwhunter(at)integra.net
Guest
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| Posted: Thu Jun 07, 2007 6:29 am Post subject: Runaway trim |
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I usually lurk, but you guys finally hit a chord.
I think having a way to disconnect the A/P and electric pitch trim is very important. Back in the mid sixties my dad was killed in a electric trim runaway incident in a Lockheed Learstar. The trim went to full nose down on climb out and the airplane pitched down into the runway killing all aboard. The circuit breakers were located under the pilot seat. Imagine trying to get to them during a runaway trim event.
Years later I had a A/P runaway on a C-402. The autopilot disconnect switches did not stop it. The circuit breaker had to be pulled. Needles to say I have been able to pull any circuit breaker involving pitch trim or A/P blindfolded.
The airplane I fly now has the hydraulic disconnect for the pitch trim in a very convenient place easily accessible by either pilot.
Rob Hunter
Wings
40432
[quote]
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jesse(at)saintaviation.co
Guest
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| Posted: Thu Jun 07, 2007 7:27 am Post subject: Runaway trim |
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One was looking at an atlas and had it resting on the top of the stick, pushing the trim. The other was filling in some flight log info. Watch out for this with trim on the stick. I wouldn’t even consider taking the trims off the stick, but that will only happen 1 time before you realize the importance of being careful not to hit that switch accidentally.
All I have seen are using the Van’s indicator for the Trim and I haven’t seen anybody use a flap indicator. I don’t think Dynon even had an indication option until quite recently. The first time I saw it on a display was a Sun-N-Fun.
Do not archive
Jesse Saint
Saint Aviation, Inc.
jesse(at)saintaviation.com (jesse(at)saintaviation.com)
www.saintaviation.com
Cell: 352-427-0285
Fax: 815-377-3694
From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Vernon Smith
Sent: Thursday, June 07, 2007 10:27 AM
To: rv10-list(at)matronics.com
Subject: RE: Runaway trim
Any idea what caused the trim run away in the RV10s? Was it accidental activation of stick mounted swtiches or some other problem?
On a side note, are people with Dynons using the Van's supplied trim and flap indicators or the Dynon option?
Vern Smith (#324 fuselage)
do not archive
From: jesse(at)saintaviation.com
To: rv10-list(at)matronics.com
Subject: RE: Runaway trim
Date: Thu, 7 Jun 2007 09:09:29 -0400
I have heard 2 stories of how the -10 was inadvertently trimmed nose-up while the auto-pilot was engaged. The a-p held until it couldn’t hold anymore and then let go, putting the plane in an unusual attitude VERY quickly. The first one had the original servo and the second was with a high-torque servo, which was more dramatic. If the first pilot hadn’t mentioned his experience to the second pilot, he said he probably would have wet his pants, if not more. I put just about everything on a pullable breaker. Lights and fans and stuff like that, as Tim mentioned, can be on fuses, but having everything on breakers so you can shed load manually if you have an alternator failure, which DOES happen, is a good idea. Breakers cost about $16 each for the good Klixon ones, so 20 of them is going to cost just over $300, but probably less than $300 more than you would spend on the alternative. Just being able to shed loads when you are working on settings with the plane off is well worth it, IMHO.
Jesse Saint
Saint Aviation, Inc.
jesse(at)saintaviation.com (jesse(at)saintaviation.com)
www.saintaviation.com
Cell: 352-427-0285
Fax: 815-377-3694
Hotmail to go? Get your Hotmail, news, sports and much more! Check out the New MSN Mobile [quote] [b]
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CJohnston(at)popsound.com
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| Posted: Thu Jun 07, 2007 7:57 am Post subject: Runaway trim |
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About this trim stuff – I was reading some flying mag awhile back, and there’s some new airplane out there that has a momentary switch in the pinky position that you must be holding to actuate the coolie hat for trim. I was thinking seriously about copying that. The only downside I can see is the loss of a switch position on the stick, and the very slight added complexity inline in an important system (very slightly increasing the possibility of failure – ie one more thing possible to fail, but highly unlikely). What say you all? I think it’d become automatic after a couple flights – hold the pinky button down, and actuate the coolie hat for trim. Then you’ve done away with all the accidental bumping, chart nudges and the like, and it also has the added bonus of being sort of child-proof! Although I’d still go with Tim’s recommendation of having the trim function be switch-off-able on the co-pilot side. What say you all?
cj
#40410
fuse/finishing/stuff
www.perfectlygoodairplane.net
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bhughes(at)qnsi.net
Guest
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| Posted: Thu Jun 07, 2007 8:52 am Post subject: Runaway trim |
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Would a circuit like this be useful? Any downside?
Bobby
40116
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ed(at)muellerartcover.com
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| Posted: Thu Jun 07, 2007 9:10 am Post subject: Runaway trim |
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Jesse (and others),
I've done that more then once (hit he trim with an atlas) in my Beech
Duchess. The A/P was set up to disengage when the trim activated. You
knew at once something had happened. Down side was flying an approach
IFR. If I had the heading engaged and was managing vertical descent
manually, I couldn't use the trim without having the A/P shut off.
Can't have everything I guess.
Ed Mueller
RV10 #525
On Jun 7, 2007, at 11:26 AM, Jesse Saint wrote:
| Quote: |
One was looking at an atlas and had it resting on the top of the
stick, pushing the trim. The other was filling in some flight log
info. Watch out for this with trim on the stick. I wouldn’t even
consider taking the trims off the stick, but that will only happen 1
time before you realize the importance of being careful not to hit
that switch accidentally.
All I have seen are using the Van’s indicator for the Trim and I
haven’t seen anybody use a flap indicator. I don’t think Dynon even
had an indication option until quite recently. The first time I saw
it on a display was a Sun-N-Fun.
Do not archive
Jesse Saint
Saint Aviation, Inc.
jesse(at)saintaviation.com
www.saintaviation.com
Cell: 352-427-0285
Fax: 815-377-3694
From: owner-rv10-list-server(at)matronics.com
[mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Vernon
Smith
Sent: Thursday, June 07, 2007 10:27 AM
To: rv10-list(at)matronics.com
Subject: RE: Runaway trim
Any idea what caused the trim run away in the RV10s? Was it
accidental activation of stick mounted swtiches or some other problem?
On a side note, are people with Dynons using the Van's supplied trim
and flap indicators or the Dynon option?
Vern Smith (#324 fuselage)
do not archive
From: jesse(at)saintaviation.com
To: rv10-list(at)matronics.com
Subject: RE: Runaway trim
Date: Thu, 7 Jun 2007 09:09:29 -0400
I have heard 2 stories of how the -10 was inadvertently trimmed
nose-up while the auto-pilot was engaged. The a-p held until it
couldn’t hold anymore and then let go, putting the plane in an unusual
attitude VERY quickly. The first one had the original servo and the
second was with a high-torque servo, which was more dramatic. If the
first pilot hadn’t mentioned his experience to the second pilot, he
said he probably would have wet his pants, if not more. I put just
about everything on a pullable breaker. Lights and fans and stuff
like that, as Tim mentioned, can be on fuses, but having everything on
breakers so you can shed load manually if you have an alternator
failure, which DOES happen, is a good idea. Breakers cost about $16
each for the good Klixon ones, so 20 of them is going to cost just
over $300, but probably less than $300 more than you would spend on
the alternative. Just being able to shed loads when you are working
on settings with the plane off is well worth it, IMHO.
Jesse Saint
Saint Aviation, Inc.
jesse(at)saintaviation.com
www.saintaviation.com
Cell: 352-427-0285
Fax: 815-377-3694
Hotmail to go? Get your Hotmail, news, sports and much more! Check out
the New MSN Mobile
http://www.matronics.com/Navigator?RV10-List
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Tim Olson
Joined: 25 Jan 2007
Posts: 2878
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| Posted: Thu Jun 07, 2007 9:14 am Post subject: Runaway trim |
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I think it would add more confusion, because now you can
accidentally reverse the trim too. That's what the
trim switch goes up and down for, so it shouldn't be
needed. Chris's suggestion of 2 switches is a good
enough one for the worry-worts, but if you protect your
wires from chafing and you don't include any funky
microprocessor type stuff in the trim, there shouldn't
be an extreme amount of worry to be had. You still have
to be ready for the possibility, but the standard
system is very simple. As far as dual-switching goes,
you could just as easily add a panel switch to disable
trim so you have active:
pilot only
co-pilot + pilot
no trim
Then in cruise you could disable the trim once you're
set in cruise. But, the problem with this is, when
you NEED the trim, you may find you forgot to activate
it...not good. Now you're more at risk of inadvertently
losing the ability to trim. So I'm just for keeping it
very simple and sticking with the norm....or if someone
invented a dual stick switch, great.
Additionally, for trim speed devices, I'm not a fan of
microprocessor type systems. I think that 3-way airspeed
type switch option is best....fast, or slow, depending on
airspeed. At least then the worst that could happen is that
you have fast or slow trim when you don't want it. The
fast trim would be full 12V power, the slow would be nice
to have as a pulsed DC system. As long as it's just the
power feed coming in, you shouldn't have to worry about
anything actually throwing your trim suddenly out of whack.
Tim
Bobby J. Hughes wrote:
| Quote: | Would a circuit like this be useful? Any downside?
Bobby
40116
------------------------------------------------------------------------
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Dave(at)AirCraftersLLC.co
Guest
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| Posted: Thu Jun 07, 2007 9:16 am Post subject: Runaway trim |
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I've flown in at least two planes when the elevator trim switch was sticking. One was on my old GlaStar with an Infinity grip, the other was on a Ray Allen grip with the four buttons for u/d/l/r. In the case of the Ray Allen grip, the button would get caught under the housing of the grip. They replaced it free of charge.
There was a GlaStar fatality a few years ago that wasn't explained but seemed to me like it might have been runaway trim. I tested how long it would take and how dramatic it would be in my plane. It did take a long time but once it started to accelerate nose down, the rate seemed to increase exponentially. The RV-10 elevator trim, with the motor at full speed, changes much faster than the GlaStar and more suddenly.
As a few have mentioned by the time you notice the problem, cutting power probably won't help much. Recognizing the problem and recovering smoothly is the solution. That's easy to say as I type here calmly, but hard to do with the trees rushing up...
My 10 has a trim C/B switch next to the throttle, flap switch, and A/P switch. I installed a speed reducer activated by having the flaps being fully retracted. Another strategy I've seen is to use a momentary normally open pinkie switch (MNOPS?) in the trim selector ground wire, so it takes two commands to activate trim. It's a little clumsy but it would prevent the "atlas on the trim swicth" scenario, or the case of a faulty main switch, which is not unheard of.
Dave Saylor
AirCrafters LLC
140 Aviation Way
Watsonville, CA
831-722-9141
831-750-0284 CL
www.AirCraftersLLC.com
40394, wiring, just recieved AF3400EE...sweet!
[quote][b]
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Vern(at)teclabsinc.com
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| Posted: Thu Jun 07, 2007 9:28 am Post subject: Runaway trim |
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I like it! If I don’t have a lap full of stuff I don’t feel like I’m really flying:) If a Ray Allen G207 or G307 grip (or comparable) was used. The PTT could be moved to one of the positions on the top of the stick and the momentary switch under the index fingerer could then be used as the “trim safety switch.”
Those planning on using the Advance Flight Systems EFIS have the additional notification of the trim indicator popping up on the efis display when the trim activated. Just have to watch for it and recognize the implications of it appearing in flight.
Vern (#324)
From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Chris Johnston
Sent: Thursday, June 07, 2007 8:56 AM
To: rv10-list(at)matronics.com
Subject: RE: Runaway trim
About this trim stuff – I was reading some flying mag awhile back, and there’s some new airplane out there that has a momentary switch in the pinky position that you must be holding to actuate the coolie hat for trim. I was thinking seriously about copying that. The only downside I can see is the loss of a switch position on the stick, and the very slight added complexity inline in an important system (very slightly increasing the possibility of failure – ie one more thing possible to fail, but highly unlikely). What say you all? I think it’d become automatic after a couple flights – hold the pinky button down, and actuate the coolie hat for trim. Then you’ve done away with all the accidental bumping, chart nudges and the like, and it also has the added bonus of being sort of child-proof! Although I’d still go with Tim’s recommendation of having the trim function be switch-off-able on the co-pilot side. What say you all?
cj
#40410
fuse/finishing/stuff
www.perfectlygoodairplane.net
[quote][b]
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CJohnston(at)popsound.com
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| Posted: Thu Jun 07, 2007 10:08 am Post subject: Runaway trim |
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Yea – I doubt that I’d use the “trigger” position for anything other than PTT – I’d probably put the “trim safety switch” under the pinky or somewhere else (in the case of an infinity grip).
cj
--
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GRANSCOTT(at)aol.com
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| Posted: Thu Jun 07, 2007 10:29 am Post subject: Runaway trim |
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Several times I've flown in the C 182 G1000 with pilots that try to over power the AP once it's engaged...and I've had to throw the circuit breaker on the AP as the automatic trim in motion got going--and in the 182 the auto trim will run out before it stops when it's trying to correct the additional inputs on the AP. At least there is an audible command that tells you that the trim is working against the inputs by the pilot. After resetting all was well, and then you look over at the guy that supposed to be PIC and ask them what they had in mind when they ham fisted the controls, setting off the automatic trim...duh, was trying to make the plane turn faster than 1/2 standard rate...so they grabbed the horns and started yanking...it's not nice watching your nose pitch up suddenly then fall below the horizon even faster as the auto trim is rolling trying to correct the physical inputs.
There are three ways to disengage the trim and 7 ways to disengage the AP in the new C 182's...I'd think that you'd want several disengage options in the 10 also...switches/fuse's/circuit breakers/bus panels...main and sub panels depending upon your configuration. When the planes come out of the factory, they have a castle knob on the AP circuit breaker which resides just in front to left seat and it's located for a right handed pilot on the avionic's bus. If you just reach out in the dark you can immediately feel that this breaker head is different from all the others and can quickly pull it, if needed. Maybe adding this cover on top of the circuit breakers maybe something to consider as you install your set-ups.
Patrick
See what's free at AOL.com.
[quote][b]
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rvbuilder(at)sausen.net
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| Posted: Thu Jun 07, 2007 10:30 am Post subject: Runaway trim |
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Couple of other options. Aircraft Extras has a airspeed switch that can be used to reduce trim speed at higher airspeeds thus reducing sensitivity. You could also just use a switch to do the same thing. Another option would be to put the standard rocker switches on the panel for the co-pilot and a DPDT switch with an off position to select between them. In that case you have the option of disabling one of them should it be a switch problem and still have control.
F1-Rocketboy used to sell a trim control unit that would do things like disable the copilot controls if the pilot was running trim and I believe also watch for runaway trim. For some reason he doesn’t have any reference to his products on his site anymore. Not sure if he stopped selling it but sent him an email to find out.
Michael Sausen
RV-10 #352 Limbo
From: owner-rv10-list-server(at)matronics.com [mailto:owner-rv10-list-server(at)matronics.com] On Behalf Of Dave Saylor
Sent: Thursday, June 07, 2007 12:17 PM
To: rv10-list(at)matronics.com
Subject: RE: Runaway trim
I've flown in at least two planes when the elevator trim switch was sticking. One was on my old GlaStar with an Infinity grip, the other was on a Ray Allen grip with the four buttons for u/d/l/r. In the case of the Ray Allen grip, the button would get caught under the housing of the grip. They replaced it free of charge.
There was a GlaStar fatality a few years ago that wasn't explained but seemed to me like it might have been runaway trim. I tested how long it would take and how dramatic it would be in my plane. It did take a long time but once it started to accelerate nose down, the rate seemed to increase exponentially. The RV-10 elevator trim, with the motor at full speed, changes much faster than the GlaStar and more suddenly.
As a few have mentioned by the time you notice the problem, cutting power probably won't help much. Recognizing the problem and recovering smoothly is the solution. That's easy to say as I type here calmly, but hard to do with the trees rushing up...
My 10 has a trim C/B switch next to the throttle, flap switch, and A/P switch. I installed a speed reducer activated by having the flaps being fully retracted. Another strategy I've seen is to use a momentary normally open pinkie switch (MNOPS?) in the trim selector ground wire, so it takes two commands to activate trim. It's a little clumsy but it would prevent the "atlas on the trim swicth" scenario, or the case of a faulty main switch, which is not unheard of.
Dave Saylor
AirCrafters LLC
140 Aviation Way
Watsonville, CA
831-722-9141
831-750-0284 CL
www.AirCraftersLLC.com
40394, wiring, just recieved AF3400EE...sweet! | Quote: | | http://www.matronics.com/Navigator?RV10-List |
01234
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scottmschmidt(at)yahoo.co
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| Posted: Thu Jun 07, 2007 11:31 am Post subject: Runaway trim |
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I've had my trim way out before which disengaged the autopilot, no big deal just a little pitch up at 130 knots. I haven't had it disengage on pitch down but again I wouldn't expect anything too bad. I don't know what would happen if the trim was at full throw in either direction on landing but I am guessing you can over-force it. At cruise speeds I'm pretty sure you couldn't over-power it but you could quickly slow down, the pitch down would be the most dangerous. It probably would be a good idea to purchase a red cover for the trim to easily identify it.
I remember at Reno a few years ago when VooDoo of the P-51's was coming down right after the start and all of a sudden pitched up hard and went almost straight up for a few thousand feet, everyone thought he had a Mayday but he actually lost his trim tab on the elevator. It actually blacked him out and he woke up going straight up and was pinned to floor. Once the plane slowed, he was able to control it and landed with no issues. The next day he had a for sale sign on it. The pilot was an ex-motorcycle racer, can't remember his name right now.
I have a flap indicator on my plane. I have recently lost both my flap indicator and the trim indicator lights though. I have traced all the wires back to the unit themselves and I will replace them. Kinda upset they both blew on me. I love my flap indicator. I have it set so that the first knotch moves it down one light bar. It makes it very easy to check flap position at night especially.
Scott Schmidt
scottmschmidt(at)yahoo.com
---
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KiloPapa
Joined: 24 May 2006
Posts: 142
Location: Pearblossom, CA
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| Posted: Thu Jun 07, 2007 7:14 pm Post subject: Runaway trim |
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The pilot of VooDoo was Bob Hannah.
http://www.bobhannah.com/
Kevin
<snip>
I remember at Reno a few years ago when VooDoo of the P-51's
was coming down right after the start and all of a sudden
pitched up hard and went almost straight up for a few
thousand feet, everyone thought he had a Mayday but he
actually lost his trim tab on the elevator. It actually
blacked him out and he woke up going straight up and was
pinned to floor. Once the plane slowed, he was able to
control it and landed with no issues. The next day he had a
for sale sign on it. The pilot was an ex-motorcycle racer,
can't remember his name right now.
<snip>
Scott Schmidt
scottmschmidt(at)yahoo.com
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_________________
Kevin
40494
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