Per my view and what I require for a repair that I review and approve as a Static Strength DER-
Per 25.625 if you are using tested allowables to design your joint than you don't need to utilize the 1.15 factor. If you are using computed allowables (i.e. Fbru*d*t) then you have to include the...
If the repair is statically acceptable and the durability is adequate, then it is OK. I usually try to get a minimum of three rows for fastener load distribution. However, compliance to the FARs is what you are after, as long as you check the durability of the two rows and implement...
As an operator you need to know what structure is FCBS. Yes, the DAHs will provide you with a mtc program that will cover the damage tolerance requirements of the original OEM and/or STC structure. However, you also have to determine if existing/future repairs/mods require further supplemental...
Not only is there a cost associated with the FCBS list but there is also going to be a cost associated with the Compliance Document/Repair Evaluation Guideline. I am not saying that you need this data to put your OIP together, but it would sure make it easier.
If your fleet is small enough...
I made the jump (at an older age) and beware the grass is not always greener. I thoroughly enjoy doing the analysis and I have learned a lot, especially about Fatigue and DT, however, an analyst sits behind a computer in a cubicle all day, the whole job is done in a cubicle. I miss going down...
Going with a Hi-Lok would provide for a nice assortment of oversize fastener options available and a very good solution, just check your hole tolerances to ensure you are maintaining the fit that you desire. Another option would be to change to another material bolt, perhaps a Ti NAS6805 or...
If it is a "fitting" and the fitting has an offset load the actual shear stress could go up per fastener due to the eccentric load acting on the closer spaced fasteners.
For a joint you have to check:
Shear strength of fastener
Bearing of material
Tear-out of material due to short edge margin
Tear-out between fasteners
Tension failure
Transitional failure (head popping or bending, pull through, everything that can only be tested)
If you have an edge margin...
Well, I finally was able to pull quotes directly out of AC 120-77 and think that I at least got someone's attention on the documentation and substantiation requirements for a repair. In lieu of trying to "dumb" down my presentation, I just stuck with the Regs and stated that all repairs, minor...
Thanks again for your responses. I think we are all in agreement that the structure has to be shown to meet limit and ultimate loads when either repaired or damage is reworked and let go. Compliance has to be shown by some sort of engineering substantiation, what that engineering...
I am trying to prove that you have to accomplish an analysis to show that it can carry the limit and ultimate loads, even for Minor repairs or damage. To me stating that the repair or damage is minor and just stating that the "aircraft flew in that way" or "we see that damage all the time and...
rb,
thanks for your response. My interest is to disprove the old mentality of "it flew in that way, it will fly out that way" by proving that the aircraft most likely did not experience or more critically will not be able to sustain the limit load (and thus is not in compliance). I want to...
I know that Limit Load is the maximum load anticipated on the aircraft or component during its service life. My question is what is the definition of service life and how it relates to limit load. I was taught that a limit load is only to occur once in the life of a fleet (i.e. 1 aircraft out...
I think that personality (which could include enthusiasm) and smarts (which may not be actual knowledge of actual job) are the key to hiring. If you hire a smart person who fits in with your current culture, you can easily teach them the job.
However, you can hire the person with the most...
