Heads up for any one flying a 1965 to late 1968 Cessna 172 concerning elevator bell crank bracket.
I fly a 1967 172H on several occasions about two years ago friends at the airport noticed that my elevator was moving in the wind, the first several times I checked it I found nothing wrong, gust lock in place and everything appeared normal, I continued to fly my aircraft, the last time I was called I checked and found that the gust lock was in place and the cables were loose in the fuselage, much to my horror I found that the elevator bell crank bracket was broken and loose in the bottom of the airframe, I researched this problem and found that Cessna had a service bulletin Se69-4 outlining just such a problem with Cessna 172s from 1965 to 11/1968. I have been checking every 172 that I have come across in these years about a dozen so far, and found that in all but one of them with TAFT 1900H either the bracket is in the process of breaking or has been replaced. How is it possible that this is not a recurring AD on these aircraft? Elevator is a primary flight control.
By the nature of the construction and the weight of the elevator the elevator control feels normal even when the bracket is in the process of breaking, however down control could be severely inhibited, leaving a pilot unable to recover from a departure stall, there have been departure stall fatalities in these years of 172s, I have no idea if this problem contributed to the cause or not.
I found that the turn buckle in my aircraft had been adjusted at least once, probably to compensate for the failing bracket.
The other thing that frosts me is the repair kit in 1969 was $6.26 now the bracket is about $377.00 and not to mention about 30 hours of labor.

172heavy,

Do you have any photos or information on where the cracking is occurring specifically. Would like to know what to look for when doing inspections on all my customers 172's from that era that come into my shop.

Thanks.

Brian.

THANK YOU for posting this! Mine was built before 1965, but from now on I will try to remember this whenever I happen to coma across one of the affected airplanes. Is this something you could have seen from the outside of the airplane on a pre-flight?

All of you guys are staying proficient on your flight techniques in controlling the aircraft without elevator control, ain't ya ?

The bracket can be inspected through the inspection covers in the floor by the pilots seat, the easy way to tell is by the smoking /moving rivets on the belly skin just to the left of center, between the formers that house the wing struts, lay under the airplane and with the factory gust lock in, have someone lift up and down on the elevator (not to hard, duh), this will show the rivets movement , the bracket is 6-7” in length and is about 5/8”wide, it’s made of sheet aluminum bent in a U form with mounting tabs on the bottom and each end, the cracks start on the vertical tabs in the radius of the bend, fore and aft, the bottom tabs have only one rivet per tab and begin to twist as the bracket moves fore and aft, thus creating smoking rivets on the belly skin between the formers that house the wing struts, the new style bracket is heavier and has more mounting points, If your aircraft has the new bracket, on the belly, you will find three rivets per forward tab and two per aft tab, that’s a total of ten, as opposed to four on the original. If you find the bracket intact, and you do not want or feel the need to change it, discontinue the use of the factory gust lock and use an aftermarket one on the tail.
Note: If you have to do this job I will share any information and tricks that I learned, I found the factory instructions to be worthless, actualy less than, a waste of time

I have a friend's Cessna 1966 172G in my hangar now with a broken flap bell crank bracket. Any tips you may have for the repair would be appreciated. We are replacing the seat rails during the repair, and already have them removed, along with the section of floor directly above the broken bracket. Thanks, Stan

Why so specific on the year airframe-- is the bracket and/or attach configured differently on the pre-65 & post-68 airplanes?

I believe that on the earlier models, the bell crank is mounted vertically below the floor, but is mounted horizontally on the these models. Not sure what is used later . Anyway, I have a friend's 172G in my hangar now that has a mounting bracket that is toast! The new or updated mounting brackets are beefed up quite a bit, and use 10 rivets to retain it, rather than the original which only used 2 rivets.