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Key Ignition Switch
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bakerocb

Joined: 15 Jan 2006
Posts: 727
Location: FAIRFAX VA

Posted: Mon Mar 20, 2006 11:28 am Post subject: Key Ignition Switch

3/20/2006



Hello Fellow Builders, Several of us have a real dislike for the key type 

ignition switches found in many type certificated airplanes and also 

installed by builders who may just assume "that's the best way".



The following web page offers another data point on why that type of 

ignition switch is dislked by many of us.



http://www.avweb.com/news/columns/191792-1.html



OC

Bill Denton

Joined: 10 Jan 2006
Posts: 97
Location: Chicago, IL USA

Posted: Mon Mar 20, 2006 12:07 pm Post subject: Key Ignition Switch

Obviously, the article describes a skew, as it was a defective switch "out

of the box".



But, you must also look at the size of the ring of keys involved in

situations like this. If your airplane key is one of the 50 keys on that 2"

key ring, you are putting mechanical loads on the switch that it was not

designed for.



But in the interests of learning something here, how would you secure your

airplane other than with a keyed ignition switch?





--

bakerocb

Joined: 15 Jan 2006
Posts: 727
Location: FAIRFAX VA

Posted: Mon Mar 20, 2006 12:20 pm Post subject: Key Ignition Switch

3/20/2006



Hello Fellow Builders, Several of us have a real dislike for the key type

ignition switches found in many type certificated airplanes and also

installed by builders who may just assume "that's the best way".



The following web page offers another data point on why that type of

ignition switch is dislked by many of us.



Please put this in web page form starting 

here//http://www.avweb.com/news/columns/191792-1.html



OC

frank.hinde(at)hp.com
Guest

Posted: Mon Mar 20, 2006 12:51 pm Post subject: Key Ignition Switch

Yes and if the this type of switch fails on a mag it sort of fails

same...sort of...If it fails when you have both electromic ignition

sysytems running through it your engine will quit.



That is why over and over again we warn of not using ANY single single

point of failure common to both ignition systems (or fuel pumps for that

matter).



In other words you need an indvidial on/off switch for each critical

component.



Good reminder OC



Do not archive



--

frank.hinde(at)hp.com
Guest

Posted: Mon Mar 20, 2006 1:00 pm Post subject: Key Ignition Switch

You can still use a keyed switch but better to make sure it only

controls a single ignition and the starter. The second ignition will be

on a separate switch. Hard to start it unless you want to swing the prop

by hand.



Frank 



--

mprather(at)spro.net
Guest

Posted: Mon Mar 20, 2006 1:16 pm Post subject: Key Ignition Switch

Hi Bill,



With a chain around the propeller..  How about a padlock through the guard

on the toggle switch which controlls the starter?



How do you propose that a key switch provides significant security for

your airplane?  Granted, the dumbest criminals don't know how a magneto

works, but the determined ones will.  As has been discussed here in the

past, airplanes are easy to hotwire.



BTW, I don't think multiengine airplanes have keyswitches...

Matt-



[quote] 

 <bdenton(at)bdenton.com>



 Obviously, the article describes a skew, as it was a defective switch

 "out of the box".



 But, you must also look at the size of the ring of keys involved in

 situations like this. If your airplane key is one of the 50 keys on that

 2" key ring, you are putting mechanical loads on the switch that it was

 not designed for.



 But in the interests of learning something here, how would you secure

 your airplane other than with a keyed ignition switch?





 --

rv8ch

Joined: 10 Jan 2006
Posts: 250
Location: Switzerland

Posted: Mon Mar 20, 2006 1:23 pm Post subject: Key Ignition Switch

 	  Quote: 	
		   Hello Fellow Builders, Several of us have a real dislike for the key type 

 ignition switches found in many type certificated airplanes and also 

 installed by builders who may just assume "that's the best way".


	


Me too.  I'm leaning towards a canopy lock and a prop lock.  I've

also seen a very clever control stick lock.



Got any better suggestions?



-- 

Mickey Coggins

http://www.rv8.ch/

#82007 finishing

do not archive

_________________
Mickey Coggins
http://www.rv8.ch/

BigD(at)DaveMorris.com
Guest

Posted: Mon Mar 20, 2006 2:04 pm Post subject: Key Ignition Switch

I'm wondering more about the kid at Oshkosh that likes to push buttons, 

than the hardened criminal who thinks he's gonna steal an airplane with the 

word "EXPERIMENTAL" written all over it and a bunch of controls he's never 

seen before in his life.



Dave Morris

At 03:22 PM 3/20/2006, you wrote:

 	  Quote: 	
		  

<mick-matronics(at)rv8.ch>



 > Hello Fellow Builders, Several of us have a real dislike for the key type

 > ignition switches found in many type certificated airplanes and also

 > installed by builders who may just assume "that's the best way".



Me too.  I'm leaning towards a canopy lock and a prop lock.  I've

also seen a very clever control stick lock.



Got any better suggestions?



--

Mickey Coggins

http://www.rv8.ch/

#82007 finishing

do not archive

Terry Watson

Joined: 09 Jan 2006
Posts: 290
Location: Seattle, WA USA

Posted: Mon Mar 20, 2006 3:52 pm Post subject: Key Ignition Switch

In an RV-8 you could install a switch in the front baggage compartment that

disables the starter switch. You would probably only use it when you thought

there was some risk, such as leaving the plane out overnight or at a fly-in.

Locking the baggage compartment would prevent anyone from getting to the

switch.



Terry

RV-8A finishing

Seattle


<BigD(at)DaveMorris.com>



I'm wondering more about the kid at Oshkosh that likes to push buttons, 

than the hardened criminal who thinks he's gonna steal an airplane with the 

word "EXPERIMENTAL" written all over it and a bunch of controls he's never 

seen before in his life.



Dave Morris

At 03:22 PM 3/20/2006, you wrote:

 	  Quote: 	
		  

<mick-matronics(at)rv8.ch>



 > Hello Fellow Builders, Several of us have a real dislike for the key

type
	


 	  Quote: 	
		   > ignition switches found in many type certificated airplanes and also

 > installed by builders who may just assume "that's the best way".



Me too.  I'm leaning towards a canopy lock and a prop lock.  I've

also seen a very clever control stick lock.



Got any better suggestions?



--

Mickey Coggins

http://www.rv8.ch/

#82007 finishing

lhelming(at)sigecom.net
Guest

Posted: Mon Mar 20, 2006 7:46 pm Post subject: Key Ignition Switch

 	  Quote: 	
		  

 But in the interests of learning something here, how would you secure your

 airplane other than with a keyed ignition switch?


	


I secure mine by locking the canopy.  If someone wants to break the canopy 

and fly my plane with winds blasting them smack in the face, that is their 

life they will risk.



Indiana Larry



---

armywrights(at)adelphia.n
Guest

Posted: Mon Mar 20, 2006 8:11 pm Post subject: Key Ignition Switch

Bill,



Do a quick friendly ramp check on your local Bell 206 JetRanger.  There is a

key switch that enables/disables the starter circuit, but in itself has no

bearing on the operation of the start switch.  In fact the keyswitch is on

the Pilot's side of the center console beside his calf, and the starter

switch is on the collective.  I'm thinking about using some kind of

arrangement like this to disable the starter circuit on my airplane and keep

it safer from theft...



Rob

RV-10



--

brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Mon Mar 20, 2006 8:52 pm Post subject: Key Ignition Switch

Dave Morris "BigD" wrote:

 	  Quote: 	
		   

 

 I'm wondering more about the kid at Oshkosh that likes to push buttons, 

 than the hardened criminal who thinks he's gonna steal an airplane with the 

 word "EXPERIMENTAL" written all over it and a bunch of controls he's never 

 seen before in his life.


	


And that happens. I climbed into my airplane to fly in the airshow at 

OSH several years ago only to find every switch in the airplane, master 

included, turned on and battery dead. No flight for me that day.



-- 

Brian Lloyd                         361 Catterline Way

brian-yak at lloyd dot com          Folsom, CA 95630

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

- Antoine de Saint-Exupery

_________________
Brian Lloyd
brian-yak at lloyd dot com
+1.916.367.2131 (voice) +1.270.912.0788 (fax)

I fly because it releases my mind from the tyranny of petty things . . .
- Antoine de Saint-Exupery

bicyclop(at)pacbell.net
Guest

Posted: Mon Mar 20, 2006 9:09 pm Post subject: Key Ignition Switch

A throttle lock would do more good than a key switch.



Pax,



Ed Holyoke



--

nuckollsr(at)cox.net
Guest

Posted: Mon Mar 20, 2006 10:07 pm Post subject: Key Ignition Switch

At 09:07 PM 3/20/2006 -0800, you wrote:



 	  Quote: 	
		  



A throttle lock would do more good than a key switch.



Pax,


	


   . . .  or a padded chain over the prop. I've talked with

   numerous operators who prefer this method. It's right out

   in front so the midnight airplane shopper will see it

   right off. Further, it's right out in front where any

   attempts to removed it (time consuming) is more

   likely to be observed. It's inexpensive even when the

   hardest chain and locks are used and one size fits most.



http://www.aeroelectric.com/Pictures/Misc/AC_Theft_Protection.jpg



   A keyed mag switch is only a slight inconvenience. I once

   lost the key to a rental machine and brought the

   airplane home by breaking the p-lead terminals off the

   back of the mags with my fingers, hand-propped the

   airplane and came home. 20 minutes with a crimp tool

   and strippers repaired the 'work-around' and I cut some

   new keys from the office spare. Others have told me

   that they did similar work-arounds by breaking the

   terminals off at the mag switch. One or the

   other is easy to get at. If you're really

   crude . . . a pair of diagonal wire cutters works too.



   Bob . . .

aerobubba(at)earthlink.ne
Guest

Posted: Tue Mar 21, 2006 4:30 am Post subject: Key Ignition Switch

 	  Quote: 	
		  

 But in the interests of learning something here, how would you secure your

 airplane other than with a keyed ignition switch?

 I too will be locking my canopy.  In addition, there will be a specific
	


switch configuration for starting.  For example, when shut down, all

switches will be off.  While in operation, a certain minimum number of

switches will be on.  For starting, there will be one of those 'minimum for

flight' switches that will be off.  This is a DPDT, with the start

contactor circuit using one set of contacts.  Anyone not familiar with this

configuration will not be able to crank my plane.  Those who don't have as

complex an electrical system could easily do the same sort of thing by

requiring the dome light to be on, or an auto pilot armed, or the baggage

light to be on, or any other switch not normally associated with engine

starting.  The bad guy will most likely assume a problem with the plane and

move on.  Of course, a prop lock will tend to make him select an easier

target before breaking into your plane...  



Glen Matejcek

aerobubba(at)earthlink.net

harley(at)AgelessWings.co
Guest

Posted: Tue Mar 21, 2006 5:06 am Post subject: Key Ignition Switch

Morning, Glen...

I too agree that a canopy lock is probably the best route.  Maybe both 

that and the prop chain.

Sure, a prop lock would prevent them from flying off with the plane, but 

if all they are after is the neat avionics that we experimental builders 

tend to install....

If they REALLY want the plane or avionics, then they smash the canopy, 

and/or they call their friendly neighbor with a flat bed truck.

We can't prevent all attempts of thievery if someone really wants it, 

but at least the canopy lock will keep the little kids from touching the 

instruments and switches with their peanut butter coated fingers when 

we're not around.

Harley Dixon

Long EZ N28EZ

Glen Matejcek wrote:

 	  Quote: 	
		  >But in the interests of learning something here, how would you secure your

>airplane other than with a keyed ignition switch?

>

 I too will be locking my canopy.  In addition, there will be a specific

switch configuration for starting.  For example, when shut down, all

switches will be off.  While in operation, a certain minimum number of

switches will be on.  For starting, there will be one of those 'minimum for

flight' switches that will be off.  This is a DPDT, with the start

contactor circuit using one set of contacts.  Anyone not familiar with this

configuration will not be able to crank my plane.  Those who don't have as

complex an electrical system could easily do the same sort of thing by

requiring the dome light to be on, or an auto pilot armed, or the baggage

light to be on, or any other switch not normally associated with engine

starting.  The bad guy will most likely assume a problem with the plane and

move on.  Of course, a prop lock will tend to make him select an easier

target before breaking into your plane...  

Glen Matejcek

aerobubba(at)earthlink.net

BigD(at)DaveMorris.com
Guest

Posted: Tue Mar 21, 2006 5:40 am Post subject: Key Ignition Switch

I've got a throttle quadrant from an F-100 and I'm going to use one of the 

switches on top of the handle for my starter switch.  That way I don't have 

to take my hands off the throttle or stick to do an in-flight restart.  The 

key switch on the ignition is just for the ignition, and the starter won't 

run with the key off either, but you don't turn the key to crank the starter.



http://www.davemorris.com/Photos/Dragonfly%20Electrical/WiringTheCenterSwitchPanel.jpg



Dave Morris



At 12:02 AM 3/21/2006, you wrote:

 	  Quote: 	
		  

<nuckollsr(at)cox.net>



At 09:07 PM 3/20/2006 -0800, you wrote:



 >

 >

 >A throttle lock would do more good than a key switch.

 >

 >Pax,



    . . .  or a padded chain over the prop. I've talked with

    numerous operators who prefer this method. It's right out

    in front so the midnight airplane shopper will see it

    right off. Further, it's right out in front where any

    attempts to removed it (time consuming) is more

    likely to be observed. It's inexpensive even when the

    hardest chain and locks are used and one size fits most.



http://www.aeroelectric.com/Pictures/Misc/AC_Theft_Protection.jpg



    A keyed mag switch is only a slight inconvenience. I once

    lost the key to a rental machine and brought the

    airplane home by breaking the p-lead terminals off the

    back of the mags with my fingers, hand-propped the

    airplane and came home. 20 minutes with a crimp tool

    and strippers repaired the 'work-around' and I cut some

    new keys from the office spare. Others have told me

    that they did similar work-arounds by breaking the

    terminals off at the mag switch. One or the

    other is easy to get at. If you're really

    crude . . . a pair of diagonal wire cutters works too.



    Bob . . .

steveadams

Joined: 10 Jan 2006
Posts: 191

Posted: Tue Mar 21, 2006 7:46 am Post subject: Re: Key Ignition Switch

Back to the original post. As far as I know, most common production GA aircraft use a keyed starter switch. I understand it can fail, just like any other switch. I also understand redundancy is usually a good thing, however you need to balance redundancy with complexity and risk potential. You also have to ensure that your "fix" is not more failure prone than the original. I'm no expert, but there are a lot of experts designing and building aircraft you start with a key. Of the millions of flights made with a keyed switch, how many accidents have been attributed to a failed switch? Are there any service letters, SB's, or AD's addressing a problem with the switch? I'm not trying to be argumentative, but I have a keyed ignition switch as called for in my aircrafts design, and wonder if this is really something that I should be concerned about.

brinker(at)cox-internet.c
Guest

Posted: Tue Mar 21, 2006 7:49 am Post subject: Key Ignition Switch

This may have been discussed before. I was thinking about 

putting a simple toggle switch in an out of the way place maybe under the 

instrument panel on the pilot side or even under the cowl close to the 

firewall on the outside. If it we're outside no one would even notice that 

you switched it on during preflight and what thief would ever suspect or 

understand such a setup. I think my main concern would be an avionics thief 

tearing up my instrument panel and stealing multiple thousands of dollars 

worth.



Randy



---

jlbaker(at)telepath.com
Guest

Posted: Tue Mar 21, 2006 8:28 am Post subject: Key Ignition Switch

Are there any service letters, SB's, or

 	  Quote: 	
		   AD's addressing a problem with the switch?


	


http://tinyurl.com/j3m5j

Jim Baker

580.788.2779

'71 SV,  492TC

Elmore City, OK

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