Page 11 - June Volume 10 Volume 6

I told him to taxi back to the shop, tell them he had spoken to me about the problem, and have them smack the OSG solenoid with a mallet. That did the trick.
I gave that pilot the same advice – quit testing the overspeed governor because you’re just asking for a stuck solenoid.
The Power Lever Double-Check
Back in the ‘70s and ‘80s, we had a chronic problem with solenoids sticking open. We would do the final ground runs on a King Air and everything would be fine, but when the owner went to leave, one prop wouldn’t come up to takeoff rpm. It happened a lot and it was maddening.
In response, I formed the habit of releasing the test switch and running the power levers back up through the test zone. This way, if the solenoid stuck open after the test, I could catch it on my ground run and fix it before the owner picked up his aircraft. To this day, if I touch that OSG test switch, I do a double-check with the power levers afterwards.
In the old days, those solenoids failed so frequently that we kept them in stock. I don’t know if it was a vendor problem or a change in design, but the tendency for stuck solenoids on the overspeed governors seemed to lessen over time. It still happens, however, and always at an inopportune time. Being able to identify and fix the problem is very handy.
Malletization Beats Beaucoup Bucks
So why didn’t I replace the solenoid in that B200, or tell the E90 pilot to have his replaced?
Once you look up the price you’ll see why. They have become absurdly expensive. Currently, the price at Beech (Textron) is a hair below $7,000.
Malletization, or hitting something with a soft-blow hammer, is a
JUNE 2016
KING AIR MAGAZINE • 9