Gust Locks, pt 2

[donv]

This is a great article from the Twin Commander website, about what happens if you leave the airplane for a while with no gust lock on:

https://flightlevelsonline.com/2013/winter-2013/torqued-off-a-true-tail-of-failure-to-follow-a-simple-rule/

I haven't had that happen, as I am very careful about installing both internal and external gust locks, but you never know, especially if you let someone else use your airplane!

[Badger]

The same thing happened to me on a layover in Colorado Springs in August of 2020.  A line person removed the rudder lock to tow the aircraft (not necessary, but they often do that) and neglected to reinstall it.  The overnight wind gusts from the Rockies broke the rudder torque tube. Fortunately, I discovered the lack of rudder control during my preflight the next morning and called for a local mechanic to come look at my aircraft (500B).  We got it fixed in about 5 days, but it was not an experience that I would ever like to repeat.  My interior gust lock and my rudder gust lock both get installed whenever I park the aircraft. 

[Adam Frisch]

Had to repair my rudder torque tubes and stops on the old 520 for same reason.

[JimC]

I still haven't found a commercial source for external gusts locks. Anyone know of one?

[JimC]

Also, I'm replacing one of the long oval inspection plates on the tail with a plexi window. You can look inside and see the rudder internals during preflight.

[donv]

I would think Aero Air could either find one or build one for you.

I still haven't found a commercial source for external gusts locks. Anyone know of one?

[Bruce Byerly]

Also, I'm replacing one of the long oval inspection plates on the tail with a plexi window. You can look inside and see the rudder internals during preflight.

It is cool to have a window to look at stuff but I’m sure it’s not approved -  what do you really gain? Checking the torque tube integrity is easy? Plexi is good for a Cub I’m thinking.

As far as rudder locks, the internal is good and gives the cushion of the system and doesn’t scratch. An 1/8 piece of rubber sandwiched by some wood stays in place and scratches less too. Not a hard thing to fabricate.

[donv]

I would just point out that the AFM recommends using both internal and external gust locks.

[JimC]

re: tail window

I heard there could be twisting damage that could be present without a full torque tube failure? Is this likely or not?

[Bruce Byerly]

If you put a lock in, there’s really no chance of damage to the TQ tube sitting on the ground. That said, everything wears out. And judging by the pilots I’ve seen flying around at 200 KIAS or more with the ball mostly displaced, or leaving the plane without a lock, who knows what else is going on, bent, or damaged.  But I don’t see where a plexi window will be worth it other that to marvel at some machinery. You can’t really see sheared rivets in a torque tube.

Then there are the crappy repairs, etc. Take care of it and it’s extremely reliable. Let a Gulfstream blow it hard over while you’re in the FBO drinking coffee and poof, $25k out the window.

For the first time in a long time, yesterday I started up with the lock in place. I was distracted after the fueler at Dolphin aviation walked around the plane 3 times trying to figure out where to fuel the plane. After we talked and found a screwdriver, I checked the caps, etc I was refreshing myself on auto start override as I hadn’t used that in 15 years either. Got out of routine and forgot the external lock.  Fortunately a customer was watching and came out to advise and helped me out by throwing it in the baggage. Embarrassing for sure, but I wouldn’t have made it 10 feet without figuring it out as I move the pedals a lot when taxiing. Last time I did that I was in the Shrike and could duck out the back door to remove without shutting down. Anyway, reminded me that the only real way of a pilot can check for integrity of the TQ tube is to leave the external lock in place and push on the pedals.

[appleseed]

"Anyway, reminded me that the only real way a pilot can check for integrity of the TQ tube is to leave the external lock in place and push on the pedals"

Bingo!

Short of mechanic tearing into the plane. This is how you can check integrity if you have any doubts about the plane being abused/neglected outside of your watch.

If you still aren't sure, you can do what glider pilots do, a positive control check. It requires an assistant standing outside to gently resist control surface movement  through the full range in both directions.

[Big Pistons Forever]

A company I used to work for had a fleet of Turbo Commanders. After someone took off with the external lock on they modified the lock so it held the rudder defected about 10 degrees. When you got in it was immediately obvious if the lock was still on, as the rudder pedals were displaced

[Bruce Byerly]

Just touching the pedals will make it immediately obvious. Or following a checklist. 

I’ve seen folks put some tabs into the wind so that it makes it easier to kick out. Just remember to take your N# off of it before sending into someone’s back yard.

[donv]

I can only think of one time that I forgot the external gust lock. It was in an 840, and I was distracted getting everyone loaded up. I hopped in, started up, checked the pedals... and sure enough, gust lock in. Only thing to do was to shut down, get out, take it out, and start the whole process over. Embarrassing, but nothing you can do. It was about 20+ years ago, so I have that going for me.

[Big Pistons Forever]

So, so far 2 pilots have said they started up with the gust lock in place. Maybe there is a better way than the conventional faired lock……