Repairing an Engine Mount (Looking for Advice)

[ShyFlyGuy]

I have a Cessna 152 and while on it's latest flight, a part of the motor mount broke. If anyone is familiar with the Cessna, the nosegear is integrated into the mount, and is held rigid by two supporting, lower braces. Those braces are visible by looking at the airplane head-on, and extend to the nosegear outside of the cowling. The crack is conveniently located at the weld-spot.

I have heard of someone having the motor mount being repaired without having to remove the mount and send it in (thus, also saving the hassle of removing the motor). Has anyone heard of this, and if so, let me know where it is done? Feel free to post away if you've got advice, but PM me if you know of a shop who can repair it. I hear FI doesn't take to kindly to free advertising.

Shy

 

[erj-145mech]

Sorry to say that your mount is going to have to be removed to repair. First, according to 14CFR43, Appendix A, its considered a major repair. After its weld repaired, the hardness of the steel in the heat affected area of the repair is going to be altered by the heat as a result of the repair, and the mount is going to have to go into a large oven to normalize the mount as a whole assembly.

I beleive that it is also spelled out in the Cessna maintenance manual.

 

[ShyFlyGuy]

Sorry to say that your mount is going to have to be removed to repair. First, according to 14CFR43, Appendix A, its considered a major repair. After its weld repaired, the hardness of the steel in the heat affected area of the repair is going to be altered by the heat as a result of the repair, and the mount is going to have to go into a large oven to normalize the mount as a whole assembly.

I beleive that it is also spelled out in the Cessna maintenance manual.

Thanks man! That is the same info that I've come up with. I'm gonna have to send it out for an overhaul. We'll take it from there. Thanks for the info!

Shy

 

[TrafficInSight]

good time to powder coat it if it's not already.

 

[ShyFlyGuy]

good time to powder coat it if it's not already.

I was thinking about that, but is there a benefit to that?

Shy

 

[TrafficInSight]

I was thinking about that, but is there a benefit to that?

Shy

Most of ours are powder coated but we have a few that aren't... yet.

The ones that aren't powder coated the paint peels off and they get rust spots on them and we end up having to clean the rust and repaint the sections a lot... but then the paint peels again. It's very rare that the powder coating gets damaged.

 

[erj-145mech]

How do you find a crack or a defect if it is below the powder coat? Is it possible that you could develope a crack in a weld after the powder coat is applied, and not find it on a visual inspection?

I havent found an STC for this application, what are the legalities for using it?

edited to add STC comment.

 

[TrafficInSight]

How do you find a crack or a defect if it is below the powder coat? Is it possible that you could develope a crack in a weld after the powder coat is applied, and not find it on a visual inspection?

I havent found an STC for this application, what are the legalities for using it?

edited to add STC comment.

It's not specifically approved or prohibited. AC43.13 talks about organic coatings as a way to combat corrosion but doesn't specifically mention powder coat. The Jeppesen airframe textbook mentions it as an excellent high durability coating for things like "engine mounts and landing gear struts." Not regulatory, obviously.

We send the engine mounts out for repair and they come back powder coated. No one's ever called us on it.

You'd find a crack under the powder coat the same way you'd find a crack under the paint.

 

[erj-145mech]

However, A.C. 43.13 is not valid in this particular case, as the Cessna 152 (subject aircraft) maintenance manual calls out specific repairs to the engine mount. Refinishing after the repairs is also covered. Is powder coating called out in the 43.13? Where is the Jeppesen handbook designated in the approval process?

Powder coating is more flexible than ordinary paint, so a crack could develope under the coating, and could go undetected. They would not be an indication in the coating. So, nobodys called you on it. You've been sucessful in hiding it. Its not the FAA that you have to be worried about, its the insurance company. The FAA is down sizing, and they are counting on the insurance companies to enforce the regs for them, where it gets the most visibility, your pocket book. If they can get out of paying a claim, due to any technicality, they will. The airworthiness certificate for the airplane is not valid at that point. If you read the fine print on that certificate, you would read someting to the effect that it is not valid if the aircraft is not maintained in accordance with the current regulations.

If its not an approved procedure, then its an unapproved procedure, correct? Its got to be one or the other, right? Is the person who is signing the bottom line on the 337 aware of the re finishing?

If you are not the airplanes owner, is the owner aware that he is paying you for gambling with his assets?