The Cessna 120-140 Association Forum

Hey,

Finished up the annual on my 1946 140 yesterday N72911. the IA found some "wiggle" in the vertical stabilizer. Not a lot, but it is there. the bolts are intact and I have a tool on the way to get behind the bulkhead in the front of the vertical stab to access the nut so I can tighten things up. Have not looked at the rear bolts yet.

there is that AD about the bolts and this was accomplished by another shop a few years ago and I do not know their procedure. the IA there is long gone.

So -- my question is this: Is there a way to access and tighten these bolts without a lot of dis-assembly of the tail area? No, I am not skinny enough to crawl down the inside of the fuselage.

Any hits, pictures suggestions and whatever would be very welcome. To contact me directly use my email: Kevgar@gmail.com

Thanks, Kevin Garrison

Please take your time and do it right, as You don't want the Vertical to come off in flight!

If the holes are walleyed, try some close tolerance bolts or the next size up!
(my opinion)

The front nut/bolt can be tightened with a bent closed end wrench thru either of those access holes, I think I took a torch to a cheap box end wrench and bent it to what I needed, simple enough. Do not over-tighten. Here's what the bolt hole looks like on the fuselage sans vertical fin and horizontal stab...
The rear vertical stab bolts go into nutplates. These nutplates are part of the stabilizer and not the fuselage bulkhead. You do not want to strip those nutplate threads or you will have to do major surgery. Here's where those are...look at the top 2 bolts.
The AD you refer to is 48-07-01

Inspect the two bolts attaching the horizontal stabilizer to the fin post for tightness and proper length. If no bolt threads extend through the fiber lock rings of the anchor nuts inside the stabilizer attachment fitting (how on earth would you check that?), or if the bolts show any indication of having backed off when checked with a wrench, they should be replaced with AN 4-5A bolts on Serial Nos. 10091 and up, or AN3-5A bolts on earlier serial numbers. In making the tightness check use caution to avoid stripping the threads in the anchor nut. If the new bolts do not develop at least 3 inch-pounds torque in the anchor nut, AN 4-H5A or AN 3-H5A (drilled head) bolts should be substituted and safetied together with wire. Check the clearance of the elevator horn and horn bolts with respect to the cutouts in the fin spar and increase it to a minimum of 1/8 inch wherever necessary.

(Cessna Service Letter SLN-52 dated 02-04-48 and SLN-52A dated 03-03-48 and SLN-52B dated 05-04-48 covers this same subject.)

Those 2 bolts are in shear so they don't need to be reefed down.

The bottom 2 or 4 bolts that the rudder hinge bearing is attached to are also held by nutplates in the back. Some birds have 2 bolts, some have 4 bolts here. Don't over-tighten these.