Page 16 - Volume 14 Number 8

MAINTENANCE TIP
Troubleshooting Tips for King Air AC
How’s the air conditioning (AC) in your King Air right now? This time of year, my phone is burning up with air conditioning problems due to everything from low Freon to the dreaded Black Death. If your AC is acting up a little or not working at all, there are things an owner/operator can check before calling the shop. The more info you can give your mechanic, the more efficiently they can fix the problem.
Please don’t mistake my intentions here; this is not a replacement for your POH, nor is it official training of any kind. I’m just offering some troubleshooting tips for the more typical problems found in King Air air conditioning systems.
Low on Freon
The most common problem with weak AC is low Freon. You need a shop with the proper equipment to measure
14 • KING AIR MAGAZINE
by Dean Benedict
how much is in your system and whether it needs more Freon added or taken away. Over-servicing Freon is as bad as not having enough. Make sure you know whether your system takes R12 or R134a. Many King Airs built with an R12 system have been converted to R134a and there should be a corresponding STC in the POH. The Maintenance Manual or the STC will specify the exact amount of Freon your system takes. A pound over or under will greatly affect performance.
If the system is empty or very low, your shop needs a sniffer to find where the Freon is leaking. Such leaks need to be fixed. If the system is down just a little, it’s probably the normal seepage inherent in most AC systems – rarely are they completely airtight.
The balance of this article applies to the 200/300/350 series King Airs. The AC system in these models has more components and therefore more places where the system can break down. My apologies to the
AUGUST 2020