Airframe/Structural Repair 1

[begbie553]

Hi All.
I am a systems man by trade, and wm now in an enviroment which requires certification of Airframe/Structural Repair.

It is an alien concept after many years of never having to go near it.

Does anyone know of a good book, guide etc for self study of Principles etc..
This would be a huge help.

Many thanks.

 

[wes616]

Hi Begbie,

There are many many books discussed on this forum. Read through some of the old posts and do a search (as well as take a look at the faqs).

For a starting place, take a look at the Flabel book, "practical stress analysis for aircraft design engineers".

Also spend some time reading through AC43.13.

Good luck to you!

Wes C.
------------------------------
Light travels faster than sound. That's why some people appear bright until you hear them speak.

 

[prost]

How do you certify the repair without a Designated Engineering Representative (DER)?

 

[berkshire]

Throw it back in the air and see if it flies?

 

[DC1000]

prost, it is not even legal to perform a major airframe repair without filling out a form 337 and having your plan of action approved by the FAA.

 

[begbie553]

"How do you certify the repair without a Designated Engineering Representative (DER)?"

Eh ? It has just became apparent that this is a U.S site.
I am assuming of course.

As a Licensed Aircraft Engineer you hold certification rights iaw Aircraft SRM and/or in my case a Boeing Approved Repair Scheme.

I just want a book that takes you back to basics but covers all aspects to refresh the old grey matter and catch up a bit before the signing begins...Thats all.

Then of course throw back in the air and see if it flies !

 

[berkshire]

begbie553 (Aeronautics)
Joking aside , which government entity are you working under. FAA, CAA, LBA. or other ?
Most but not all of the posters on this site work on American registered aircraft. Hence the responses you got.
The other question is are you working heavy or light aircraft? You could try the "Standard Aircraft Handbook for Mechanics and Technicians" for basics or AC-65.15A Airframe Handbook - FAA then if you need something more advanced Go to Peery or Flabel or Bruhn.
Good luck.
B.E.

 

[crackman]

Just as a note and regardless of whether or not you are workinng under EASA or the FAA, a certified repair station can approve minor repairs per the FAR definitions contained in Appendix A of FAR Part 43 for the FAA of course. Now if the repair is major and you are in the USA, in addition to a 337 you will need an FAA DER or the FAA ACO to approve. This gets more complicated under EASA or other european authorities. It really amounts to whether or not your are a delegated engineering company and what you are delegated with. If the delegation does not cover it (ie repairs to critical areas), then the EASA or equivalent agent must sign it. Also EASA finally published their bilateral agreement with the FAA regarding minor and major repairs and STC's. Fairly convoluted.

As for guidance, Boeing has many documents and training manuals on airframe repairs. In fact, my best recommendation would be to get sent to the Boeing Airframe Repair course which they offer (or at least use to) to liasion engineers at the airlines and authorized repair centers. It is a very good training course and its on the mark as it addresses real world repairs.

 

[prost]

begbie553: doesn't matter what you call it in your own country, so the term DER can mean "any authorization to perform a repair on certain classes of air vehicles." I never meant to restrict the discussion to the US; however, almost every country, I think, has laws about who can certify structural repairs or designs for certain classes of air vehicles.

You said that you were in systems engineering; typically in the US systems engineers do not do structural analysis and therefore would not be DERs or similarly authorized by your country's governing civil aviation authority.

 

[wes616]

you were in systems engineering; typically in the US systems engineers do not do structural analysis and therefore would not be DERs

Actually if we want to get really technical, you need to specify tht Structural DERs perform structural analysis & cert, and Systems DERs perform systems analysis & cert.

Why must we assume that something illegal is about to happen. Can't this be a legitimate question from a professional colleague who has changed jobs, asking a group of professionals for some educational material to "get him up to speed." It is quite a difficult endeavor to switch from systems to structures and vise versa.

Probablly should have searched before posting, though.

Wes C.
------------------------------
Light travels faster than sound. That's why some people appear bright until you hear them speak.

 

[prost]

My question wasn't about legalities, per se. My question was regarding whether just opening a few references was enough, since there are often many other issues such as certification, which carries with it the legalities of who can certify and under what circumstances. Despite how brilliant anyone is, he/she still can't certify any repair without the proper credentials as specified by the governing aviation authorities.


Oh never mind...

 

[737eng]

Sign up and take the BAC Training Class - Aircraft Structural Repair for Airline Engineers Part I, let it sink in for 6 months or so and then take Structural Repair for Airline Engineers Part II. These two classes will give you the basics and be a great refresher course.
In addition, I recommend: Bruhn, Niu's books, Flabel, and depending how deep your getting possibly Broek's practical fracture mechanics book.
OEM Design and Repair Manuals are also excellent resources, however, they are harder to come across anymore.
If you are into something you are not comfortable or don't fully understand, consult with a co-worker who is familiar or contact the OEM for assistance.

 

[SeaKing1998]

read airframe structural design by

MICHAEL CHUN- YUNG NIU

 

[toddec]

This is way easier than it is being made out to be. The aircraft manuals provide approved data which can be used to perform repairs without additional approval. Many repairs in the SRM are MAJOR repairs and no additional work or approval is needed to perform the repair, but the accomplishment of the repair must be tracked.
If you are outside the scope of the repair, there are now two paths to go down. 1) The published repair will fix the problem but you have to make minor changes to the repair -- this can be considered MINOR and not require additional approvals IF your internal Major/Minor decision tree allows it 2) You are developing the repair based off of experience or published repairs but the changes are not minor or there is no existing data - if your internal Major/Minor decision tree determines this is a MAJOR repair FAA approval must be obtained. The appproval can come from a DER (8110-3), the OEM (8100-9 for Boeing or RAS for Airbus), SFAR36 if your company is designated or an FAA office.
The key is that MAJOR repairs cannot be performed without APPROVED data whereas MINOR repairs (or MINOR changes to APPROVED MAJOR REPAIR DATA)can be performed with accepted data. If your company has an engineering group that is allowed to write MINOR repair procedures, that is all that is required. Most companies usually require two signatures on their paperwork, but some allow a single signature for minor repairs. It all comes down to what your company's Repair Station Manual or General Maintanence Manual or whatever document you have to live by says. I know American Airlines lets Co-Op students write repairs and sign them, but they have to have a lead or manager signature as well.

 

[Joa38]

737eng... could you provide more information on how to take the BAC Training Class?

Thanks.

 

[toddec]

Joa38... don't know if 737eng is still following this thread or not, so I'll let you in on the secret. The Boeing training is now done by Alteon, which is a Boeing company. Their website has all of the course info and the like. It is

http://www.alteontraining.com/

You need to look for a link to the "Per Seat Courses" to find the class. The Structures I class is a two week course that used to cost about $3k. If there are several people at your company that need the class, they can set up a class at your facility for a much better rate (don't have cost of airfare, rental car and hotel for two weeks).

Hope this helps.

 

[sigma38]

Looked and looked but couldn't find the course offered. Thanks for the suggestion. I went ahead and started another specific thread with the same question.

Thanks again.

 

[HANDCALC]

Sigma 38,

Your answer is waiting at your other post:

http://www.eng-tips.com/viewthread.cfm?qid=187821&page=1

Handcalc