This is an old Airworthiness Directive that has been around so long, that many airplane logbooks may have had a "complied with" logbook entry years ago. Inspectors need to verify this and not just assume that once complied with means always complied with. It is possible that the required device could have been removed or lost during re-build. That's what happened on my Taylorcraft. CAP recommends that Taylorcraft owners and operators should re-visit this important safety issue.
The AD came about as a result of an accident where a pilot inadvertently turned the FUEL OFF when he intended to pull CARB HEAT ON. This is an easy mistake to make if you are not looking at the knobs but rather going "by feel". The knobs are right next to each other.
As a safety remedy, Taylorcraft came up with a simple clip device that installs on the fuel shut-off knob. The AD says... "Taylorcraft P/N B12-947-3 or equivalent is considered satisfactory."
Read the Full Text of the AD Here.
One major problem is... This part is not available anymore. OK so the next option is to come up with an equivalent one. But the next problem is.... what is it supposed to look like? Are there any old-timers still around that might know? For me, the solution has come through the Taylorcraft Forum and from some internet searching. It all boils down to this... We need a device that meets the intent of the AD. And the good news is that the AD gives the following as a clear description of the intent:
"The device is to prevent inadvertent operation of the fuel shutoff valve by requiring a definite and positive movement by the pilot before the control can be operated."
Well here is what I came up with for my airplane: I fabricated this myself as an "owner produced part".
It is the small silver device that is mounted with the fuel shut-off control anchor nut. I made it from .032 Aluminum 2024-T3. I made it in such a way that I believe it meets the intent of the AD. You have to move it slightly downward to turn fuel on or off. Some folks worry about fatigue, so they have made them from spring steel. But on mine, fatigue isn't an issue. I have had this in there now for the past 150 hours or so and it works great. I just made it so that the movement is not so much that you are yielding the aluminum.
After researching this a bit, I patterned this after one that I saw on the Taylorcraft Forum, which I believe might be an actual Taylorcraft part. See the red clip in the photo below.
Another fellow posted this one he made from a broom-handle clip. It is a spring-steel device that should suffice. It just looks like it might be difficult to operate (in my opinion).
Either way, I believe all of these designs do meet the intent of the AD and may help save some souls from an inadvertent engine out circumstance.
Fly Safe - and Keep the Antiques Flying!