Page 17 - August 2015 Volume 9, Number 8

The connecting rod that blew the hole in the compressor case, shown on page 12.
It got worse. After four days, the pilot had to yank his aircraft out of the shop for that important trip (with no A/C in triple digit temperatures). He managed to swing by my shop for a look-see, but he only had a few hours. With three guys we had it diagnosed in about an hour. Using the sniffer, we determined the system was not leaking, but we found other issues. First, it was still a tad low on Freon. Sometimes it’s that last half a pound, or even a few ounces, that makes all the difference. Second, we found the switch that turns the A/C off below 50o F was inoperative. And third, we found the condenser blower was intermittent due to a loose terminal block.
This was good news considering the other shop had seen stains on the condenser and therefore assumed it was leaking Freon. They had no sniffer, so they were shooting in the dark.
Based on guesswork alone, they had recommended the condenser be changed. This is a very expensive part and an extremely labor-intensive job. Although the pilot couldn’t stay for us to fix the problems we identified, he was thrilled to know exactly what was necessary to get that A/C system blowing
cold again. He was even happier to
know that their recommendation
to change the condenser was
completely unnecessary.
Moral
The moral of the story is this: Make darn sure you know what kind of Freon your King Air takes and find out the exact refrigerant capacity of its A/C system. Make a note of this somewhere other than the logbooks, because when your A/C goes out you probably won’t have the logbooks handy.
AUGUST 2015
The most common problem is that the system is a little low on Freon. This does not imply there is a leak somewhere. The maintenance manual states clearly that it is normal for the system to lose a few ounces per year. If you haven’t serviced it in 18-24 months, it could be down just enough to compromise the cooling capability.
If it’s more than just a low-Freon problem, then find someone that has a knack for air conditioning with King Air capabilities and equipment. In a cool King Air cabin, everyone’s happier. KA
If there is a particular maintenance issue you would like Dean to address in a future issue, please email Editor Kim Blonigen at kblonigen@cox.net.
About the Author: Dean Benedict is a certified A&P, AI, and has 40 years of experience in King Air maintenance. He is president of Honest Air, Inc., which specializes in Beechcraft King Air maintenance and repair.
KING AIR MAGAZINE • 15