Eric M. Jones
Joined: 10 Jan 2006
Posts: 565
Location: Massachusetts
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 Posted: Wed Aug 22, 2007 5:38 am Post subject: LED Position and Anti-collision lighting. |
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Let's put this discussion where one can find it...
| Quote: |
Hello James, You wrote: "Eric himself does not believe that present
commercial units meet the FARs, but for experimental, they do not need to."
I am questioning your statement that stobe and position lights installed on
amateur built experimental aircraft do not need to meet FAR requirements. What is your basis for that statement?
A) Each amateur built experimental aircraft will have a set of Operating
Limitations that are part of that aircraft's special airworthiness
certificate. The Operating Limitations will include the words:
"After completion of Phase I flight testing, unless appropriately equipped
for night and/or instrument flight in accordance with 91.205, this aircraft
is to be operated under VFR, day only."
B) FAR Sec. 91.205 paragraphs (c) (1) and (2) read:
"(c) Visual flight rules (night). For VFR flight at night, the following
instruments and equipment are required:
(2) Approved position lights.
(3) An approved aviation red or aviation white anticollision light system on all U.S.-registered civil aircraft......skip....."
C) Here is a quote from the introduction to my table on the subject of
amateur built aircraft equipment requirements:
"The builder should note that some items required by the FAR's are
described in the FAR's as needing to be approved, but since there are no
certification standards established for amateur built experimental aircraft,
no formal individual item approval, such as meeting a TSO (Technical
Standard Order) or FAR Part 23, is required. However certain items must
interface properly with ATC (Air Traffic Control), other aircraft, or other
entities external to the aircraft. Transponders, communication radios,
exterior lighting and ELT's (Emergency Locator Transmitters) are examples of such equipment. Therefore, the builder can expect that the initial airworthiness inspection of his aircraft will require evidence that this
type of equipment in the aircraft is acceptable to the FAA."
D) It would appear that the inspector performing the original airworthiness inspection of an amateur built experimental aircraft would have the prerogative of insisting that the strobe and position lights of that
aircraft (if installed) meet the requirements of FAR Part 23 regarding
strobe and position light performance. The presumption being made that the installation of such lights indicates an intention to fly at night on some
occasions.
Bob wrote: "if one had LED based position and strobes, then perhaps
night VFR on 8A would be quite comfortably managed."
This is a good point, and opens up the topic of LED position lights. I
have a Jabiru J400, and the alternator is good for 20 amps max, closer
to 15 amps continuous. I had planned to put an SD20 alternator on the
crank splined shaft to get more total power, but the complication of two
alternators and two batteries seemed far too great for what will be
mainly a day and night VFR plane with pretensions.
The Whelan strobe and position light system has two lamps per wingtip
and the strobe supply. Each lamp is two amps, and the strobe supply is
6 amps. Yikes! That is 14 amps for running lights. The gold plated
pins that go into DB connectors and also the circular plastic locking
connectors are very easy to use, but should not be used for much over 4
amps. I could parallel these critters, but that gets to be more work.
By going to the LED system from either Kunzleman or GS, the current draw is between 150 and 300 ma per wingtip. The strobe systems run 2 to 4 amps.
Are these wingtip nav lights equivalent to the Whelan incandescent? I
have bought both GS and Kunztleman systems for testing. I just made a
simple turntable marked off in degrees to rotate the wingtip unit to
measure lux output vs. angle. I'm using the nice primer on lighting
requirements that Eric Jones posted on his website, Perihelion Designs.
http://www.periheliondesign.com/
To measure the light output, I got a lux meter, calibrated in lux.
Photographic light meters can be converted from exposure value to lux,
but these meters are intrinsically logarithmic in response, and I don't
trust it.
The horizontal plane measurement will be relatively easy, but the
vertical plane may be harder. Eric himself does not believe that
present commercial units meet the FARs, but for experimental, they do
not need to. Of course, the low power strobes don't, but any strobe is
far better than none, and the logarithmic response of the eye comes to
our rescue here.
James Foerster, J400, wiring. |
| Quote: |
Time: 06:14:24 AM PST US
From: "Fergus Kyle" <VE3LVO>
Having read the discussion this topic regarding Running Lights (Nav Lts?)
and the pro-/anti-Whelen sides, it occurred to me that perhaps another tack be taken.
The coloured lights are there so that (like ships) an early estimate
of direction of travel be made in order to plan evasive manoeuvres if
needed. In that case, the lights are not just for our protection but for the
Others out there. That's what I think the U.S. regs require - service to
other flyers. If they don't satisfy the particular standards drawn up, they
don't protect other aircraft - and that could be 300 people.....
That's why I've chosen an approved source for lights.
Ferg
Europa 914 mono |
I have some concern that the FAA will tighten up exterior lighting requirements, probably after some very public night accident, but for now you get your airplane signed off as VFR-day flightworthy and the rest seems up to your good judgement and the insurance company.
I agree with Ferg that the position and anticollision lights are for the protection of others, so we should insist that other builders design for safety all around. Don't be shy. Not just your own life is at risk. I have made offers to test LED position lights made by other but got no takers.
I state categorically that many LED lighting systems are not per the FAA specs. See my website for information.
I have sold some position lights that ARE per the FAA specs. One of my customers landed using only the LED position lights to see the runway. An amazing accomplishment. But the LEDs were really really bright.
I am planning to reintroduce these later, but others will enter the field with good systems too. For now I am working on too many other things.
Exceeding the FAA specs would be in the best interest of builders who may want LEDs but don't want to certificate them or buy certificated parts. It is also true that the differences in LEDs (soon 4-10X the luminous efficacy, essentially infinite lifetime, organic LED sheets, etc.) gives rise to vastly different schemes for placement and operation of exterior lighting.
I am interested in making a flush beacon. Ideas appreciated.
As for James Foerster's testing: It will be great to see your results. We anxiously await data.
"THE VERY BIG STUPID" is a thing which breeds by eating
The Future. Have you seen it? It sometimes disguises itself as a
good-looking quarterly bottom line, derived by closing the R&D
Department.
--Frank Zappa
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_________________
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net |
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