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View Full Version : Navigation light article? Part 23.1385-.1401



bwilson4web
02-05-2012, 10:28 AM
Hi,

I've failed via Google and the Sport Aviation archives to find a distilled version of the FAA Part 23.1385-.1401 sections covering position lights:

23.1385 Position light system installation.
23.1387 Position light system dihedral angles.
23.1389 Position light distribution and intensities.
23.1391 Minimum intensities in the horizontal plane of position lights.
23.1393 Minimum intensities in any vertical plane of position lights.
23.1395 Maximum intensities in overlapping beams of position lights.
23.1397 Color specifications.
23.1399 Riding light.
23.1401 Anticollision light system.

These are fine regulations but written with a stilted style common to rules and regulations. Yet I thought I once saw a Sport Aviation article that clearly showed the angles both navigation and anti-collision lights had to cover. Just I'm not having luck finding that article or anything like it. Any suggestions?

The reason is we are rebuilding the wing-tip, navigation lights of N19WT:
http://hiwaay.net/~bzwilson/dragonfly/2012/wing_140.jpg
The strobes have to go to the fuselage because their flash is reflected off of the canard. What are the coverage angles required for the red and green navigation lights?

The Part 23 regs indicate 110 degrees from front-to-side. So we'll raise the navigation light socket about 3/8" to reach the bottom lip of the clear, plastic cover. But it is the angle to the rear that we need some guidance. What is the rear view requirement for the green and red navigation lights? Do they have to be rearward visible or is this optional after the 110 degree angle side is reached?

FYI, the original navigation light measured 1,150 ma and the LED replacement just 133 ma. Best of all, the LED replacement does not need a plastic filter and filter holding hardware:
http://hiwaay.net/~bzwilson/dragonfly/2012/wing_330.jpg
The led light replaces the plastic filter, bulb, and shield holder. Raising the socket 3/8" will fully expose the LED to the front and the back-side will reflect off of the former, strobe reflector.

As for the anti-collision lights, my understanding is one on the top of the fuselage behind the canopy and a second one on the bottom at the front edge of the canard will provide 360 degree coverage yet shadow the prop, wing and canard. This way the pilot won't be blinded at night. However, I'm not committed to strobes.

I've ordered some high intensity, white LEDs that per spec exceed the 400 lumen requirement, ~1,000 lm at 1A. The existing, 1980s, Tandy strobes draw 310-340 ma. Back of the envelope suggests that operating the LEDs to cycle at 400 lumens would draw about 400 ma. The relatively low-voltage, LED electronics will be simple, low-high-OWCH adjustable, robust and reliable.

Yes, a short duration, intense strobe burst is visible from a great distance but the requirement is lumen based from the days of rotating beacons:
http://skywagoncity.com/wp-content/uploads/0531003-6-225x300.jpg
Skywagon City (http://skywagoncity.com/index.php/electrical/2011/04/rotating-beacon/)

I'm one of those pilots who had a strobe equipped Cherokee and found the 'prop stopping' flashes to be annoying at night.

Thanks,
Bob Wilson

steveinindy
02-05-2012, 02:46 PM
I'm one of those pilots who had a strobe equipped Cherokee and found the 'prop stopping' flashes to be annoying at night

You said you're aircraft has a canard so that would normally mean a pusher configuration so this shouldn't be an issue.


Do they have to be rearward visible or is this optional after the 110 degree angle side is reached?

I don't believe so (don't hold me to that.....ask Chad Jensen, he would know) because of the fact it would make it difficult to tell if the plane was headed towards you or away.