Prop knob lock?

[201er]

I've seen some photos of Mooney panels with a padlock over the prop knob. I don't really understand the point of this? Surely you can start and fly a plane without being able to bring the RPM back? What is this for?

[Seth]

Hi Mike-

I know at certain airports certain safety measures are taken to ensure props have chains or locks physically on them.  I do not know if this is for safety of the airport or safety of the airspace - for instance, one of the DC 3 airports (those in the FRZ) at one point had to, and I'm not sure if this is still required, actually have a lock externally on the the prop.  Now I do not know if that is still required, but a true theif or troublemaker would not let that deter them - really it's for perception only to a degree.

I'm guessing the "lock" of the prop knob is similar, but realy that is only speculation.  Required by the terms of the lease on the tie down / hanger area, or due to specific operating procedures for security purposes.

This is a very unofficial answer, just speculation.

Take care,

-Seth

[Hank]

I've seen prop & throttle locks that hold everything OUT; locking the prop into high RPM would be difficult, unless you drill holes and go tightly around a structural member. Jamming in a block to hold it out, and locking it there, would be very simple.

[201er]

Image 8 on the Mooney front page gallery has one. I don't understand what that's for.

[sreid]

Quote: 201er

Image 8 on the Mooney front page gallery has one. I don't understand what that's for.

[Hank]

Oh, the joys of vintage birds! When was the prop moved to the middle? It's there in my 1970 model, and per the Owner's Manual, it's the factory location.

[rob]

Yes, it's on the Mixture - and hasn't been relocated on that particular plane (you can read the "push rich" text under the lock). But that begs the question - what good is it to lock the mixture full rich? 

[rbridges]

Quote: rob

Yes, it's on the Mixture - and hasn't been relocated on that particular plane (you can read the "push rich" text under the lock). But that begs the question - what good is it to lock the mixture full rich? 

[jwilkins]

Some airports were requiring a 'third lock' in the post 9-11 panic. The way I remember it, it could be the aircraft door, ignition, and then any 'third' lock such as a locked hanger door. At our flying club it was not required but we put a chain and padlock on the tail tie-down of the club aircraft in the shade hangers just to show how security conscious we were.

The Aircraft Throttle Lock sold by ACS doesn't fit the Mooneys; you can however custom order the vernier version milled out to a larger ID from the manufacturer. 

When I was traveling around to a couple airports where the 'third lock' was supposed to be required I bought a Master Lock bicycle cable lock which was entirely plastic coated (including the lock) to put on the prop. It was not high security but it met the requirements. A couple times I forgot to put it on and never heard any complaints / reminders. For some time I carried it in the baggage compartment in case I got 'reminded'. I don't think it's even in the plane anymore. If you wanted to have an inexpensive and visible lock with at least some security there are some heavy duty cable locks made for motorcycles that would work better than the bicycle lock.

Jim

[Seth]

Quote: jwilkins

Some airports were requiring a 'third lock' in the post 9-11 panic. The way I remember it, it could be the aircraft door, ignition, and then any 'third' lock such as a locked hanger door. At our flying club it was not required but we put a chain and padlock on the tail tie-down of the club aircraft in the shade hangers just to show how security conscious we were.

The Aircraft Throttle Lock sold by ACS doesn't fit the Mooneys; you can however custom order the vernier version milled out to a larger ID from the manufacturer. 

When I was traveling around to a couple airports where the 'third lock' was supposed to be required I bought a Master Lock bicycle cable lock which was entirely plastic coated (including the lock) to put on the prop. It was not high security but it met the requirements. A couple times I forgot to put it on and never heard any complaints / reminders. For some time I carried it in the baggage compartment in case I got 'reminded'. I don't think it's even in the plane anymore. If you wanted to have an inexpensive and visible lock with at least some security there are some heavy duty cable locks made for motorcycles that would work better than the bicycle lock.

Jim

[Bennett]

In the past (over 20 years ago) I purchased both throttle and mixture cylindrical locks from Aircraft Spruce. These slipped over the knobs when pulled out, and they have an unusual circular lock with a "half" key. I still have one of them (no idea what I did with the other one), and I use it and a prop lock (stainless steel motorcycle lock in a leather sleeve) when I am in remote sections of Mexico. The best (interior) security system I ever had was a sheet of aircraft aluminum, cut to completely cover the panel, (shaped exactly to the panel contours),with two half tubes ("D" shaped) welded perpendicular to this plate, and which dropped over the yoke shafts. It had a pin arrangement and lock on the lower part of the "D" shaped half tubes that would not let the unit be removed without removing the pin and lock. The yokes were pulled back to allow these half tubes to fit in place. Really nice setup to protect valuable avionics, and with aircraft aluminum, the device was quite light weight. As I recall it also a drop down section in the middle that covered the throttle, prop , and mixture knobs when they were pushed in. I kept it in the baggage compartment when not needed (Mexico and Caribbean). It was made and marketed strictly for Mooneys, and I bought it locally in San Carlos. Lent it to a friend who was heading south, and I never got it back. Dang! I should have a new one fabricated.