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I recently did an annual inspection on a Rockwell Commander, and the gear warning light was not working.

Before we tell that story, I want to thank our sponsor, PilotWorkshops.com

This week’s “Tip of the Week” was about emergency checklist memorization… a very interesting lesson by Sarah Fritts, a West Point graduate and Army combat aviator.

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I also discovered Sarah Fritts has a website with fantastic training resources at ThinkAviation.net

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Now back to the gear warning light… after some troubleshooting, I discovered there was proper voltage at the light assembly and the ground connection was good, so it had to be the bulbs.

Sure enough, those little mini bulbs with soldered wire strands were the culprit… there are two of them.

I was super excited to find a batch of 7 or so of these on eBay, only to discover they were not working… how frustrating! Back to the drawing board.

I finally found some appropriate bulbs from another source, soldered them in the light socket, and they worked perfectly!

Another mystery with this Commander 114 landing gear system was solved a couple years ago after the owner had a huge yaw in flight… it turned out the landing gear was extending during flight. Since the gear is hydraulic, the one with least resistance came down first, and created a yaw effect.

It turned out the emergency extension valve was leaking internally past a worn o-ring, and causing the gear to extend.

Here’s the knob near the pilot’s right knee… the knob is connected to a hydraulic valve.

This issue was perhaps more difficult to troubleshoot since the gear warning light was also not working.

Now, both squawks have been fixed, (the valve was replaced a couple years ago, and the light was fixed during the most recent annual inspection.) Now, hopefully the system will operate normally for a long time.

One last item for today… check out an exhaust valve I recently lapped in a TSIO-550 cylinder for an owner… it showed very early signs of burning, but was still in good condition:

We lapped the valve and installed a new rotator, hopefully extending the life of this cylinder.

The post “163 – Gear Warning Light Mystery” appeared first on AirplaneOwnerMaintenance.com