Are vehicle strobe power supplies suitable for EAB

Discussion in 'Instruments / Avionics / Electrical System' started by wb2754, Nov 7, 2018.

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  1. Nov 7, 2018 #1

    wb2754

    wb2754

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    Just curious if Whelen vehicle strobe power supplies are safe and suitable for use in experimental homebuilts, and if so, what type/ configuration?
    Is anyone using something from a different application or something "homebuilt"?

    Thanks,

    William
     
    Last edited: Nov 7, 2018
  2. Nov 7, 2018 #2

    TFF

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    I dont know, but the Whelen airplane ones are. Joking. As a homebuilt, its just gota work. Its up to you to decide. Personally I would be looking at LED strobes.
     
  3. Nov 7, 2018 #3

    Marc Zeitlin

    Marc Zeitlin

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    Safe? Sure. Legal? 14 CFR Part 91 requires "approved" lighting for both day, night and IFR flight. If you have lights, they're supposed to be "approved". The old version of Part 23 clearly called out what that meant - the new version is a bit vaguer.

    So it's POSSIBLE that non-aviation strobes will meet the definition of "approved" lights and all that requires, and that should theoretically be enough. And if you're installing them on an aircraft that already has an AC issued, the chance of getting caught or checked by the "strobe police" is essentially nil. But I know of a few folks that installed non-approved (read Non-TSO'd here) lights on their EAB aircraft and had the DAR deny the AC until they took them off of the plane.

    So, YMMV.
     
  4. Nov 7, 2018 #4

    Dana

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    Whelen makes their "Microburst" strobes, non TSO, for experimentals, then specifically says they're not approved for night flight per 91.205, wink wink nudge nudge...

    www.whelen.com/pb/Aviation/Product Sheets/MicroBurst_Flyer.pdf

    But, reading 91.205 it looks to me like it's legal to install them and use them for better visibility during daytime operations, though not necessarily legal to fly at night with them... so a DAR should have no problem signing off on the installation.

    But then, the FAR definitions state:

    So to whom does the FAA "delegate authority"? Anybody can "approve" an experimental for return to service after a modification...
     
  5. Nov 7, 2018 #5

    BJC

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    Good question.

    My understanding is that E-AB aircraft may install position lights that have been tested and shown to meet the technical requirements and be legal for night operations.

    Is there a citation to the contrary?


    BJC
     
  6. Nov 7, 2018 #6

    Toobuilder

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    I and friends use the Whelen automotive power supplies, flash tubes and eBay automotive LED bulbs for our lighting. I'd happily compare them to the TSO'd versions from a performance standpoint. No issues on any front.
     
  7. Nov 7, 2018 #7

    TFF

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    Visibility wise LEDs are way better. Day time and night time, at least double the range you can see them. LEDs don't seem as bright just looking at them but some how it is either the color of the light or the dwell of the flash or a combo, but i notice them. In the day time its the only lights I see, unless right up on an aircraft. The plus of the LEDs is also power draw; probably a tenth of a traditional strobe. Same opinion on the other bulbs. The only thing I don't like is the aesthetics of the LED, thats pretty minor.
     
  8. Nov 7, 2018 #8

    Marc Zeitlin

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    91.205(b)(11) says:

    (11) For small civil airplanes certificated after March 11, 1996, in accordance with part 23 of this chapter, an approved aviation red or aviation white anticollision light system. In the event of failure of any light of the anticollision light system, operation of the aircraft may continue to a location where repairs or replacement can be made.

    So even for day VFR, the anticollision light needs to be "approved".

    Can't answer that. But given that you have to be able to "prove" that a thing meets the TSO requirements, even in an EAB (if you built your own transponder, which is legal to do, you'd still have to prove that it met the TSO requirements for a transponder. Good luck with that :)). Obviously, proving lights meet the requirements is easier.
     
  9. Nov 7, 2018 #9

    Marc Zeitlin

    Marc Zeitlin

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    Nope - what you say is the legal truth (not just for night flight, but day as well, as indicated by 91.205(b)(11). But not all DAR's/FSDO's will accept the truth, as we know, so my point was just that one should protect one's self and take the conservative route during AC issuance. And even if they accept it, you MAY have to show proof that the lights (transponder, whatever) meet the technical requirements.

    As Toobuilder points out, if you choose the right non-TSO'd equipment, it can be as good or better than the TSO'd. But if you install it AFTER AC issuance but before first flight, there will be no potential approval problem. Same with your homemade transponder that meets the TSO requirements.
     
  10. Nov 7, 2018 #10

    BJC

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    Thanks, that is what I thought.

    My son-in-law designed, built, tested and documented compliance with 91.205 criteria a set of LED position lights for my project. Not a simple task, but he is an EE with a masters in Optical Engineering, and a research and development lab full of certified test equipment.

    BTW, casual observation of a popular offering for homebuilts seems to suggest that they do not meet the FAA’s criteria.


    BJC
     
  11. Nov 7, 2018 #11

    Dana

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    I don't think that's correct, because 91.205 by itself applies only to aircraft with standard airworthiness certificates. When 91.205 is referenced by an experimental's operating limitations, it's only in reference to night flight.
     
  12. Nov 7, 2018 #12

    Marc Zeitlin

    Marc Zeitlin

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    We've had this discussion before with respect to a few areas. There is nothing in any OL's or FAR's that exempts EAB aircraft (or any E aircraft) from Part 91 requirements. The fact that 91.205 is only explicitly called out in the OL's for night/IFR flight does not, in my interpretation, exempt an EAB aircraft from the requirements of 91.205 for day flight.

    In fact, my OL's explicitly say:

    "This aircraft is governed by the operating roles contained in the FARs, 14CFR 91, and is subject to the following OL's:"

    This is a blanket indication that part 91 applies.

    The OL's don't explicitly call out many OTHER paragraph of part 91, but no-one makes the argument that EAB aircraft aren't subject to the rest of part 91 just because the OL's don't mention it. For example, the OL's don't mention 91.207 at all, but we still need ELTs. They don't mention 91.211, but we still need supplemental oxygen.

    A lack of a mention is not mention of a lack. The FAR that we're not subject to is part 43, because part 43.1 explicitly exempts experimental aircraft. 91.1 only exempts part 103, 101 and 107 vehicles - NOT Experimental aircraft.

    I don't buy the "not subject to 91.205 except for night/IFR" argument, but I know that some do, even given the logic above, of which I've never seen a valid refutation.
     
  13. Nov 7, 2018 #13

    Dana

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    That pretty clearly says that it applies only to standard category aircraft... which is why it then has to be explicitly referenced in the operating limitations for experimentals, like part 43 appendix D for condition inspections. In other areas of part 91, they don't explicitly say "standard category aircraft" so those rules apply to all aircraft.

    I also suspect an established outfit like Whelan got legal advice before offering their non-TSO Microburst lights for experimentals, while stating "not for night operations."
     
  14. Nov 7, 2018 #14

    Marc Zeitlin

    Marc Zeitlin

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    That's one way of interpreting it. But not the only way. It doesn't say that it ONLY applies to std cat. aircraft - it just explicitly says that it DOES apply. However, I'll grant that your explanation of the interpretation of 91.205 DOES make more sense, and for 91.205 alone, does seem to exempt EAB aircraft except as called out in the OL's. Point for you :).

    Agreed.

    So back to the OP's question - non-TSO'd (or more specifically, lights not meeting TSO'd requirements) would by this interpretation be legal on EAB aircraft ONLY for day VFR ops, but NOT for night/IFR.
     
  15. Nov 7, 2018 #15

    Toobuilder

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    And on the practical side of things, one only has to look at the plethora of options (DIY and manufactured) that the RV crowd uses. Those guys LOVE rules, yet you never hear of any violations for lighting. This is a case where "...close enough..." Seems to be OK.
     

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