Bendix Ignition Switch AD Revisit

[cliffy]

I thought it might be a good idea to revisit this ubiquitous AD as there seems to be a lot of miss information going around on it. 

 The AD deals with the switch being bad and having a hot mag with the key in the off position OR even with the key removed

Many know of the "check" but only check it in the OFF position

Just going to OFF does NOT check the switch or comply with the AD   Both the AD 76-07-12 and the Bendix SB 583 specify that the inspection entails turning the switch to OFF and then trying to see if it will go beyond OFF and let the engine to continue to run. If it continues to run BEYOND OFF the switch is bad. This is done at IDLE power to avoid bad things happening while its being checked. 

If bad the switch can be very easily repaired with new internal contacts (widely available) A new switch is not always required. 

Again its those pesky little details like actually reading the AD to comply that get missed when we play the "telephone" game.

Also IF you get new keys made be aware of what key blank you get. If you can remove the key in any position other than OFF you have a bad key blank; 

I have attached a clip from Kortopates back in 2019 dealing with this serious issue THAT CAN KILL PEOPLE IF NOT PAID ATTENTON TO!!!  ( a tip of the hat to KORTOPATES)

Virtually every plane has this one in their AD list. It really isn't worth any trouble to remove it by date code on the switch, but sure, why not if you can. In truth though every pilot should be testing this on EVERY shutdown. I am sure every pilot that earned their PPL within the last 10-15 yrs was taught to do this test with every shutdown; whether Bendix, or ACS etc. We've had way too many death and serious injuries from hot props not to do so; of course not all from flunking this test but I had to replace my switch a few years ago when the contactors became intermittent. Now that I am more experienced and seen many accidents from hot props (including a Mooney mechanic friend), In my opinion the AD doesn't go far enough. It should also include a Key check. I learned this one from a fatal accident on my field. How many of you have gotten extra ignition keys from the aviation aisle at Home Depot or Lowes? No surprise, but the only approved Bendix key blanks for making spares come from Bendix - not home depot. Make sure that with your un-approved spare key that its not possible to remove the key until the off position. I didn't learn this till a fatal accident involving a trainer where the key was removed and put on the dash and then pilot & instructor got out to push the plane back. Problem was the key got pulled out without it being in the Off position! You know what happened next sadly. I never heard but wondered what kind lawsuit entailed and the potential judgement against the owner (school) - I assumed they were sued by using "unapproved parts". I quickly checked all my keys learning this and continue to do the shutdown test on every plane i work with - AD ot not, I consider it significant safety issue.

[PT20J]

ADs are pretty easy to look up:

https://www.faa.gov/regulations_policies/airworthiness_directives/

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[RobertGary1]

Just replaced the switch. No AD. 

[carusoam]

Inviting @Chris Bopp to follow along over here as well...
 

Best regards,

-a-

[0TreeLemur]

If only MS had a moderated FAQ section.   It seems that the first post in this thread would be a fantastic entry, locked, with no commentary after it.  Anybody agree?

[Andy95W]

33 minutes ago, 0TreeLemur said:

If only MS had a moderated FAQ section.   It seems that the first post in this thread would be a fantastic entry, locked, with no commentary after it.  Anybody agree?

I agree.

I think there should probably be 3 sections: FAQ- Maintenance, FAQ- Ownership, and FAQ- Flight Instruction.

Gatekeepers would receive input from members and then post it to their section by submitting it to @mooniac58.  They would be automatically paid up as a “Supporter” and would be the gatekeeper(s) for their section.  If they were to use the section simply to build up their own business, instead of for the general good, they would be replaced as gatekeeper.

For FAQ- Maintenance I nominate @M20Doc, @cliffy, and @jetdriven.

For FAQ- Flight Instruction, I nominate @donkaye and @kortopates for a start.

For FAQ- Ownership, I nominate @gsxrpilot, @KLRDMD, and probably @carusoam.

[0TreeLemur]

8 hours ago, Andy95W said:

I agree.

I think there should probably be 3 sections: FAQ- Maintenance, FAQ- Ownership, and FAQ- Flight Instruction.

Gatekeepers would receive input from members and then post it to their section by submitting it to @mooniac58.  They would be automatically paid up as a “Supporter” and would be the gatekeeper(s) for their section.  If they were to use the section simply to build up their own business, instead of for the general good, they would be replaced as gatekeeper.

For FAQ- Maintenance I nominate @M20Doc, @cliffy, and @jetdriven.

For FAQ- Flight Instruction, I nominate @donkaye and @kortopates for a start.

For FAQ- Ownership, I nominate @gsxrpilot, @KLRDMD, and probably @carusoam.

Excellent suggestions all.