Jammed wing flaps

[Guest]

Have a long body in the shop with wing flaps which would jamb and trip the breaker, always in the same place.  Nothing was physically stopping the travel, so we disconnected the actuator from the flap torque tube, they were all free.  Then we took,the actuator out and opened the back cover.  

Here is what we found. One missing tooth.

Clarence

Edited March 20, 2019 by M20Doc

[nels]

I’d say you found the problem. Breaking off gear teeth is not an easy thing to do. I wonder what caused the failure?

[Guest]

1 hour ago, nels said:

I’d say you found the problem. Breaking off gear teeth is not an easy thing to do. I wonder what caused the failure?

We have no idea what caused the tooth to break off, there was a reasonable amount of grease in the actuator. 

Clarence

[nels]

On 3/20/2019 at 7:19 PM, M20Doc said:

We have no idea what caused the tooth to break off, there was a reasonable amount of grease in the actuator. 

Clarence

Usualy it would require some contamination like a lose piece of iron or steel mixed in with the grease and getting wedged between the mating surfaces of the two sets of gears. I assume you had a good look at the lubricant and gear box for debris?

[Guest]

7 hours ago, nels said:

Usualy it would require some contamination like a lose piece of iron or steel mixed in with the grease and getting wedged between the mating surfaces of the two sets of gears. I assume you had a good look at the lubricant and gear box for debris?

We cleaned all of the grease out, the only piece of contamination was the broken tooth.

Clarence

[nels]

I wonder if there was some runout in the pinion or mating gear? Also, maybe a bent pinion shaft or dirty or nicked mating surfaces if the pinion is mounted separate from the mating gear? Not familiar with the layout.

[Awful_Charlie]

Being a gear I suspect it is made of a hardened material. I wonder if in a previous life it got dropped or similar which set off a brittle fracture?