Ask Gulfstream for their parts and materials substitution lists or drawings or IPB, etc.
Be careful... for certified aircraft parts substitutes, already approved... no sweat. For substitutes, NOT already approved in any way by Gulfstream, or a DER, you might have an uphill fight. Where this can get really difficult is for alternate alloys/finishes/[over]sizes, etc.... or for mechanical installs.
Well I guess I should have really clarified the issue. Seat tracks are being replaced both on the LH side and someone claims that engineering gave the the ok to replace the hi loks with ply’s in difficult areas. This person decided to just randomly replace any that were in a tough spot with the alternate over 12% in a row. I’ve worked on quite a few Gulfstream a/c and never seen this allowed before.
I'm not familiar with the expression "% of substitution fasteners". Do you mean substituting Gulfstream part numbers with "stock" fasteners ?
I am familiar with Gulfstream, and that they reidentify fasteners with their own code (like I think Boeing does too). But these are going to be "reasonably" stock fasteners, possibly unusual fasteners (like Hi-Tigue rather than Hi-Lite) ... I'd've thought that you should be able to identify what the fastener type is, and coatings.
No if you check the SRM there is not an alternate. You have to get an eng. disposition to use alternates anywhere in a seat track as far as I’ve experienced. I have never seen nor have known any engineering to allow the alternate fastener to be installed where ever a tech wanted. So that’s what I’m asking because a different tech decided to install over 15 alternate fasteners in a single row of about 120 fasteners and thats against anything I’ve ever seen.! Just curious!
ok, so some tech has done some unauthorised work. You could ask him under what authority he did this ... I suspect he'll say "SOP, AFAIK" (ie normal unremarkable for him). Has Inspection signed the work off ? Then ask them. If you're doing an audit, then maybe you've found an escape (and fix the incident and the practise). For own experience says this is not a good thing, and no one here is saying otherwise. If you are "just curious" then it'd seem we here agree.
me, for myself, I can see that substitute fastener can be done, with care (to get the same fastener as the OEM part), and then this would need a RDA (Repair Design Approval) since it isn't covered by the SRM.
Just like 'rb' ... I'm not familiar with the expression "% of substitution fasteners". Do you mean substituting Gulfstream part numbers with a % mix of replacement 'alternate' fasteners ?
Well I guess I should have really clarified the issue. Seat tracks are being replaced both on the LH side and someone claims that engineering gave the the ok to replace thehi loks withply’s in difficult areas. This person decided to just randomly replace any that were in a tough spot with the alternate over 12% in a row. I’ve worked on quite a few Gulfstream a/c and never seen this allowed before.
ALSO, My curiosity is killing me...
I have been in the serious business of aerospace fasteners for +40 and the term'Ply's'... RE: fasteners... is 100% alien to me. WHAT ON THIS PLANET DOES PLY'S' MEAN in relationship to fasteners????????
/NOTE/ Every discipline in engineering has a 'standard vocabulary, representation, symbology', etc ... a few examples for fasteners...
ASME B18.12-* Glossary of Terms for Mechanical Fasteners
ASTM F1789 Standard Terminology for F16* Mechanical Fasteners [*NOT F-16]
NAS380 NAS Documents, Preparation and Maintenance, in the Inch System Of Units
NAS523 Fastener Code
NASM1515 Fastener Systems for Aerospace Applications
NASM17855 Fasteners, Screw Threaded, Descriptive Factor Symbols and Order of Notes for Engineering Documents for
NASA RP1228 Fastener Design Manual
"someone claims that engineering" ... yeah, well that doesn't stand up ... in court or in the meeting room.
as the song (Phil Collins) says "it doesn't matter if it isn't written in ink".
And someone from Engineering can endorse the replacement, but outside of the SRM, I think you need an RDA to certify the replacement ... if you're doing maintenance on the plane. if you're moding the plane you may be able to "hide" this inside the mod change, just another MRB/RNC/NCR/... "production change" (but you shouldn't).
rb... when I was a USAF field service engineer overseas I carried a single 'NO BS' 5 X 9 notebook that was numbered in-sequence for every action/call I took.
I rigorously documented everything to my notebook... #/date/time/who/where/when/what/why/how. When challenged... I would confirm by ~date, etc... what I'd done. These were my standard answers when challenged...
YEAH, OK!
NOPE!
DANG I forgot, OK
Never happened.
PS: I also had my name and contact info written on the cover... just in case I was in a hurry and had a mental fart and lost track of it. I got calls all the time... 'hey just found Your notebook'. Grrrr Thanks!!
