According to the instructor, the student pilot was practicing touch-and-go landings at the airport in Sparta, Tennessee. They heard a “pop” sound as the Cessna 172 touched down.
The student pilot initiated a go-around and then informed the instructor that the left main landing gear (LMLG) had separated from the airplane.
They flew for about 2.5 hours to reduce the airplane’s fuel load before attempting to land with the fractured LMLG.
The landing was uneventful, and the airplane came to a stop on the runway.
According to the instructor, the LMLG struck the horizontal stabilizer when it separated, resulting in substantial damage.
The LMLG spring strut was examined by the National Transportation Safety Board Materials Laboratory. It fractured where the step bracket was affixed to the spring strut. The step bracket was tack welded to the spring strut. No epoxy adhesive was present on the faying surfaces of the step bracket or spring strut.
According to the Cessna service manual, step brackets can only be affixed to the spring strut using an approved epoxy adhesive on abrasively blasted surfaces; welding on the spring strut is not permitted.
The Materials Laboratory examination also found a fatigue crack that initiated at a tack weld between the step bracket and the spring strut and propagated to a length of about 0.2 inches. The fatigue crack led to an overstress fracture during the accident flight.
Probable Cause: Maintenance personnel’s failure to properly affix left main landing gear components, which led to the failure of the left main landing gear during the accident flight.
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This March 2022 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
I recall back in the mid-1970’s there was a spate of gear leg steps coming loose on the Cessnas with tubular main gear. Cessna supplied a service kit wuth a two-part epoxy with instructions to sand the mating area, then “glue” the step back on. I also used a small Breeze clamp to hold the step, and simply left that clamp on. I seem to remember that some steps on the spring gear were overly long, and there were instructions to cut these steps down before reattaching them.
Most pilot’s don’t understand Suck , Squeeze, bang, blow.
Or how carb heat works.
I bet noy one in a hundred know how that step is connected to the gear leg.
WHEN YOU HAVE A HAMMER IN YOUR HAND, EVERYTHING LOOKS LIKE A NAIL.
Same principle goes for a stick welder!
Jerry King
JimH in CA states: “… the aircraft owner should have known that the repair was not authorized, or acceptable to Cessna.”
That would be quite a new knowledge requirement for pilots/owners.
Any pilot who owns an aircraft should have the service and parts manuals for the aircraft.
Remember, the pilot is responsible to insure that the aircraft is airworthy and safe to fly.
The mechanic does the work and signs it off….but the pilot/owner must know what was done and how it was accomplished.
I could use much more harsh words wrt the pilot….
So, since the NTSB didn’t travel to look at the aircraft, they didn’t look at the logbooks and interview the mechanic that welded the step bracket to the gear leg.
The mechanic should have his certificate revoked…if it was an A&P that did the work ??
And, the aircraft owner should have known that the repair was not authorized, or acceptable to Cessna.
Hard to believe a licensed mechanic would do that. Owner ‘maintenance’ maybe?
Never had a plane come out of annual without mechanic induced problems. I’m sure there’s better available if I wanted to scour the country.
If true, that’s pathetic. What’s your recommended solution?
Regards/J
My solution is for me. the pilot/owner, to do as much work on the aircraft as possible, with the watchful eye of an A&P.
But, we both must know what to do and how to do it.!
ie; per the aircraft service manual, and supplements.
Sounds like this guy needs to find a better mechanic, probably shopping low though. In GA maintenance, in the eyes of the owner your damned if you do or damned if you don’t. It’s no wonder A&Ps are leaving. Low pay on top of no appreciation (which you do get in airlines, but at least you’re paid).
For this Cessna, I’d bet it was either owner maintenance or an ancient mechanic who will do anything for $25.