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  • Steve

RV-8 and the Blown Flash Tube

11/25/21 - When I flew on Sunday I noticed that my right strobe was out. Since the airplane was built mostly in the last century, it has mostly last century technology and the strobes and position lights are no different. It has the old Whelen A600 Series Nav/Strobe combination that has the colored position light int he front, white position light in the back and a strobe in the middle.

Whelen A600 Series Nav/Strobe light.

I think these are old style as there is a power supply in each wing tip each driving it's own strobe. I think the newer units have a single power supply running all of them, or that may have been an option at the time and they chose this method for whatever reason.

When I bought the airplane the left flash tube was blown, but Carl was nice enough to buy a new one to go with the airplane. I think that one cost around $80. Four years later, the same thing cost $190. More than twice the price in 4 years. If one were to buy all new bulbs for just one light it would be just under $350. For light bulbs! Fortunately, for everything except the flash tube, I was able to find PMA'd bulbs that were a mere fraction of what Whelen wants. In fact, for the forward, colored lights I found LED bulbs that were way less than half of the old style incandescent bulb from Whelen.

Now, ordinarily changing a light bulb is not a major ordeal but, this is an airplane so everything is harder than it has to be. In this case, in theory, it should have been a small matter of removing the 2 screws that hold the cover on and removing the flash tube and installing the new one. But, naturally, there is a catch. The flash tube has 3 wires going into a connector and that connector will not fit through the hole in the end of the wing tip.

Cover off, eyeball dangling.
There is a little bit of a slot where the wires go in, but not big enough fo r the connector.
Flash tube with connector.
Inside of the wing tip with wires and connections.

So, I had to mark which wire went where in the connector, remove each pin and push the wires through the grommet and the hole then put the wires back into the connector. Of course, in order to do this I had to remove the wing tip. What's the big deal with removing the wing tip says you? Every time I do I run the risk of scratching the paint and the more times the screws come out and go back in, the more the paint chips around the screw holes says I.

All back together witht he flash tube lens cleaned.

I got it back together pretty easily and, for once, a maintenance action took less time than I thought it would. Even better, it works again. I was a little afraid that the power supply had crapped out. Of course, when it does, I will replace them with Aeroleds, but those are pretty spendy, so for now, I will do my best to keep it going as is.

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