Intensities of navigational lights for homebuilts

[steved]

Hello:

I have been going through the CARs and FARs to try and determine the minimum intensity/color requirements for home built aircraft.

I have seen several LED light packages and it would seem that given the number and quality of the LEDs per nav light, there is no way that these lights would pass certification.

Is there another governing body for homebuilt airplanes that gives approval to various navigational lights?

Do they have their own 'homebuilt' specifications or are they taken directly from the FARs?

So far I have been somewhat frustrated trying to locate this information. If anyone out there could help, I would really appreciate your comments.

Thanks for your time.

Regards,

Steve

[Denny of Oakland]

Steve the short answer is they are minimum intensity/color requirements for all aircraft covered in part 23, 27 and 25.

"Do they have their own 'homebuilt' specifications?" No, they have to meet the requirements of FAR 21. FAR 21.191 Experimental certificates covers most of what is required for specifications. If you think it will fly and want to built something bring your specification to your local FSDO and have them submit them to the FAA engineering office. I have only seen one experimental not fly and it was shown of Myth Busters, two of the guys I work with did not sign it off. Aircraft should be safe this one was not.

However when it comes to light intensity. FAR 23 covers these:

Sec. 23.1391 Minimum intensities in the horizontal plane of position lights.
Sec. 23.1395 Maximum intensities in overlapping beams of position lights
Sec. 23.1397 Color specifications.
Sec. 23.1399 Riding light.
Sec. 23.1401 Anticollision light system.

Intensities is by intensity (candles) See FAR 23.1391 there is a nice chart that show how much candle light you will have to meet. Also FAR 23.1389 will help so I attached it as follows:

Sec. 23.1389 Position light distribution and intensities.
(a) General. The intensities prescribed in this section must be provided by new equipment with each light cover and color filter in place. Intensities must be determined with the light source operating at a steady value equal to the average luminous output of the source at the normal operating voltage of the airplane. The light distribution and intensity of each position light must meet the requirements of paragraph (b) of this section.
(b) Position lights. The light distribution and intensities of position lights must be expressed in terms of minimum intensities in the horizontal plane, minimum intensities in any vertical plane, and maximum intensities in overlapping beams, within dihedral angles L, R, and A, and must meet the following requirements:
(1) Intensities in the horizontal plane. Each intensity in the horizontal plane (the plane containing the longitudinal axis of the airplane and perpendicular to the plane of symmetry of the airplane) must equal or exceed the values in Sec. 23.1391 .
(2) Intensities in any vertical plane. Each intensity in any vertical plane (the plane perpendicular to the horizontal plane) must equal or exceed the appropriate value in Sec. 23.1393, where I is the minimum intensity prescribed in Sec. 23.1391 for the corresponding angles in the horizontal plane.
(3) Intensities in overlaps between adjacent signals. No intensity in any overlap between adjacent signals may exceed the values in Sec. 23.1395, except that higher intensities in overlaps may be used wìth main beam intensities substantially greater than the minima specified in Secs. 23.1391 and 23.1393, if the overlap intensities in relation to the main beam intensities do not adversely affect signal clarity. When the peak intensity of the left and right position lights is more than 100 candles, the maximum overlap intensities between them may exceed the values in Sec. 23.1395 if the overlap intensity in Area A is not more than 10 percent of peak position light intensity and the overlap intensity in Area B is not more than 2.5 percent of peak position light intensity.
(c) Rear position light installation. A single rear position light may be installed in a position displaced laterally from the plane of symmetry of an airplane if--
(1) The axis of the maximum cone of illumination is parallel to the flight path in level flight; and
(2) There is no obstruction aft of the light and between planes 70 degrees to the right and left of the axis of maximum illumination.
[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as amended by Amdt. 23-43, 58 FR 18977, Apr. 9, 1993]

Denny of Oakland

[steved]

Thank you very much for taking the time to respond.

Hopefully the sections will help me find out what I need to.

Lets hope that I can easily find the sub-sections that you have refered to on the net. (I have had some problems with that as well)

Cheers,

Steve