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  1. der8110

    Major Alteration or STC ?

    Voodoo, you are a quick learner! One detail I did not mention before and you found, is that it is whoever returns the airplane to service - IA, Repair Station - or "AME" as in EASA terminology, determines whether a Repair or Alteration is Major or Minor. Another "what could go wrong with...
  2. der8110

    Major Alteration or STC ?

    Looks like you have done some research, which will help to fend off the trolls. This document delineates what MUST be STC'd: https://drs.faa.gov/browse/excelExternalWindow/5394780C328E120C862581600045B7E7.0001 There is still a lot of art in "interpreting" this document (only the FAA is...
  3. der8110

    Aircraft Certified for Ditching

    The Type Certificate Data Sheet (TCDS) is your source. If the aircraft model is certified for ditching, it will say so (Order 8110-4C, Chapter 3, paragraph 3-3.b.(22)(c)). Some more recent TCDS's will even say if it is not, for instance, on the Cessna (oops, Textron) model 680: "14 CFR 25.801...
  4. der8110

    Cable Tie Mount that fits over Stringers

    http://nylonmoldingcorp.com/Products/Wire-Routing-Devices
  5. der8110

    stress analysis fundamentals

    Probably realized all he/she/ze was going to get was a lengthy list of rhetorical questions, or a printout from an IHS subscription.
  6. der8110

    Recip fogging oil?

    Try: https://www.aircraftspruce.com/catalog/eppages/tanis1.php?clickkey=50661 for a whole kit, suitable for long term storage. All the components, and thorough instructions. Also some good rabbit tunnels to go down and get lost in (engine manufacturer service bulletins). Or try...
  7. der8110

    PMA by Identicality per licensing agreement... Same part?

    As a practical matter, nearly all PMA's by Identicality per a Licensing Agreement are made by the supplier to the OEM. Either the OEM does not want to bother with the support supply chain, or the supplier made permission to sell in the aftermarket part of the original agreement of selling to...
  8. der8110

    Seat dynamic evaluation acc. to FAA Advisory Circular

    Yes the requirement applies to all Part 25 aircraft with Certification Bases Amendment 25-64 and after. And most airliners with earlier Cert Bases used in Part 121 operations (date thresholds apply). As a practical matter, a seat manufacturer is not going to design different seats for above...
  9. der8110

    Classification FAA and EASA

    Is this wha you are looking for? https://fsims.faa.gov/Wdocs/Other/Major_Repair_Alteration_Job-Aid.pdf Look at D.13r and D.13s
  10. der8110

    Rule of thumb: Numbers of Doublers i

    SparWeb, I would partially disagree with the assertion that getting DT authority is harder now than 20 years ago. Current requirements are in Order 8100.8D (10/28/2011) Table 4-1, page 4-7: This reads the same as Order 8110.37C (9/20/98), before appointment requirements were moved out at...
  11. der8110

    Using PMA parts for specific aircraft

    No further approval would be needed to install a PMA part on any particular serial number of a model listed for the PMA. To install a PMA'd part on a model NOT listed, then yes, installation data and an approval for it would be needed. But at least manufacturing approval for the part is...
  12. der8110

    Helicopter vibrations

    Also RTCA DO-160, Section 8.0
  13. der8110

    Fatigue analysis and GAG cycles

    Sounds like the two positioning up-downs before and after the middle of the mission may be a bigger effect than you realize. Bird strike on the windshield (25.775, if you have to comply) is a one-time discrete event, so while the mission may statistically be "in the muck" for more time, the...
  14. der8110

    FAR 25.561 Applicability Interpretation Help

    There's a recent "publication" from TAD, "Lists of Part 25/26 Rules and Their Associated Advisory Circulars and Policy Statements" that lists each regulation: https://www.faa.gov/aircraft/air_cert/design_approvals/transport/rules_acs_policy/ Best part is, there are hyperlinks to the various...
  15. der8110

    How to become a CVE

    CVE actually stands for “Compliance Verification Engineer”, it is an independent checking function of the showing of compliance. Similar to some of the Administrative DER duties here in the U.S. FAA system. They perform a check that all regulations in the Certification Plan have been complied...
  16. der8110

    Required certification level on aircraft reconfiguration.

    Greetings, Cabin outfitting and subsequent modifications are not required to be STC’d (or part of the TC). They may be done by engineering approval - DER 8110-3 or ACO approval. The history is that a decade or so ago, FAA Aircraft Certification and Flight Standards got together to decide what...
  17. der8110

    Standard Parts are not DDPs (fatigue)?

    Actually they are (or should have been!), keep looking through Chapter 4/5 for examples. And if not, look at another aircraft manual. In most cases these types of parts have "super fatigue life" as you call it, just as a matter of good design practice. Either intentional or by luck. And...
  18. der8110

    External Doubler, Antenna Installation

    Good evening, My first suggestion would be to use an internal doubler for the connectors, then separate internal doublers (nutplate strips) for the attachment screws. But knowing nothing about your geometry, let's assume your hands are tied so then allow me to answer your questions directly...
  19. der8110

    Hoop stresses

    yes, very conservative to consider only the skin. A pretty easy way to account for frames is to use Flugge, NACA TN 2612.
  20. der8110

    Bolt hole eddy current inspections

    What are the thicknesses of the 3 layers? Also what type of fasteners? Bolt hole EC is typically used for deep holes, i.e., each thickness is similar to or greater than the hole diameter. Also the "3 layers" statement piques my interest, understanding that may be just a 'for instance'...

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