New memeber ... need advice boom damage.
 

Hello... I recently found this website for a friend of mine who is an owner of a Skymaster.

He recently damaged the boom in the area of the doubler for ice protection. He struck a ladder while the prop was running and it was thwn into the boom.

My question is this: What repairs are allowable in this area? I have no access to structural repair manuals..... The damage is only to the skin of the aircraft. He would appreciate any advice concerning this matter.


Thanks and Godspeed,

Jon Freeman

Posting for the owner of the aircraft

We had a similar incident with our Skymaster several years back. One person in our FSDO (where my wife works) insisted that the entire boom had to either be replaced or reskinned. He made this determination while refusing to even go look at the airplane.

In our case, the prop had hit a slug (about the size of a quarter) and slung it into the boom. The slug penetrated the skin on the inner side of the boom and broke the skin on the outer side, but did not exit the boom.

We took pictures of the damage, copied the appropriate figure from the illustrated parts catalog, marked the location of the damage and sent the package to Cessna for evaluation.

Their position was that since no structural members were damaged (Ours also was only skin damage) that repairs could be made in accordance with 43-13.

Our local shop made the repair, documented it with a form 337 which was submitted to FAA and that was the end of it.

I can fax the 337 and diagram to you if you'd like. I briefly looked for Cessna's position letter tonight and haven't spotted it yet, but if you'd like a copy of it I can keep looking. Their position letter would not apply to your aircraft as it applies to an individual situation.

Call me at 804-320-5588 if you'd like the form 337 or if you'd just like to discuss the situation.

I am usually up until about 11:00PM Eastern time.

Jim Stack

Thanks so much for the quick reply!
 

This is just the kind of info my friend is looking for. I am going to print this off for him and let him decide needs to call you.

Once again. thanks for the response... you all are great.

Thanks and Godspeed,

JON FREEMAN

I may not be remembering this correctly, but in the CPA course I believe they explained the skin in the boom *is* structural. There are no internal spars.

Open up one of the access panels on the boom and look inside. You'll see all kinds of hardware.

I have 2 holes in the boom of my O2. Repaired in VN and I keep an extra eye on them no signs of stress cracks. They pulled an AK-47 round out of the boom during restoration.