Page 14 - April 2022

9
The drain line in question runs between the front of the fuel control and the back of the HP fuel pump; it connects to a drain fitting on the pump (refer to photo on page 10). If blue stains are noted in this drain
17 line, you know the front bearing in
30
your FCU has been compromised. The migration of the blue grease is a dead giveaway.
There is the remote possibility that the FCU bearing was washed out by a fuel leak, yet the Q-tip in the drain fitting came out clean, and no blue stains are visible because the drain line has darkened. In this case, I would poke a clean swab into the drain line and scrape around.
That blue grease is thick stuff and 9 will adhere to the inside of the line.
17
The chances of all the blue grease
being dissolved and washed away 30 without a trace are slim. It would take a leaky HP fuel pump spewing
fuel onto the FCU for some time.
This drain line is easily seen in the King Air model 200s, 300s and 350s. Open the right-side cowl door and look in at the HP fuel pump filter housing; then look aft, and you’ll see a drain line. That’s it. On a model 90, it’s harder to see because the cowl doesn’t open low enough to get a straight shot at it.
The bottom line is this: If you have fuel leaking from the gang drain, you must immediately investigate where it is coming from. Pay attention to the HP fuel pump. A mere Q-tip could save you from a runaway engine and subsequent shutdown. KA
Dean Benedict is a certified A&P, AI with over 45 years of maintaining King Airs. He’s the founder and former owner of Honest Air Inc., a maintenance shop that specialized in Beech aircraft with an emphasis on King Airs. In his new venture, BeechMedic LLC, Dean consults with King Air owners and operators on maintenance management & supervision, troubleshooting, pre-buys, etc. He can be reached at dr.dean@beechmedic.com or (702) 524-4378.
12 • KING AIR MAGAZINE
APRIL 2022