Installation approval

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Burk
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Installation approval

I am looking to install LED nav bulbs in a Cessna 172. The bulbs that I am looking at have no FAA/PMA approval that I know of. The distributor boasts that they meet Fed Spec W-L 0011 and Mil-Spec-45208A and Mil-Spec-45662; are theses specs approval enough to replace the orginal bulbs with these?

Thanks,
Burk

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bob.pasch
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Burk, there's a company called Aveo Engineering in the Czech Republic who are marketing LED units in the states. You might visit their web site to glean some insight...

n14ky
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If it isn't approved, you would need to get approval. To do that you need to show compliance with 23.1385 through 23.1399 if you have a 172 R or later. If an earlier 172, you will need to research the equivalent CAR 3 requirements. AC20-74 gives a method for doing the light measurements. You can go the STC route, or possibly a Field Approval, or a DER approval. What ever route you take, it will require a fair amount of engineering and documentation to get it done right.

bob.pasch
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Dave, do you sleep with that FAA hat on?

n14ky
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Seems like it sometimes!

Burk
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I guess my question is more about can I use a Mil-Spec to justify using this as a replacement? What about AC23-47 as grounds for substituting parts for older aircraft?

n14ky
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OK, the two mil specs that you cite have nothing to do with the performance of an item. MIL-I-45208A refers to the manufacturers Quality Control Plan, and MIL-STD-45662 is their calibration plan. Since neither one identifies performance, neither would provide data to support the installation.

Since there is no AC23-47, I assume you are refering to AC23-27 Parts and Materials Substitution for Vintage Aircraft. Within that document, it states that the parts substitution still needs to meet the original certification basis of the aircraft, so you will still need to meet the original requirements as I stated in my forst post. Assuming you have an older 172 certified under CAR 3, you will need to meet the requirements of CAR 3.700 through 3.703, or you can choose to comply with the later regulations stated in my first post.

Read your AIrworthiness Certificate, the limitations state that it is in effect only as long as it is maintained in accordance with Parts 21, 43, and 91. Part 21 is what drives you to maintain your certification basis.

n14ky
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By the way, Whelen has an FAA approved solution for LED navigation lights. It may cost a couple $ more, but they have already done all the paperwork to get them approved.

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