Page 24 - Volume 15 Number 8

corrosion control, designed to be added to a Phase inspection for King Airs operating in corrosive environments. It covers the whole aircraft. I didn’t find anything major, just a little corrosion up in the tail that would be easily remedied by the shop using the standard protocol for corrosion correction. I was in and out in a day; the rest of that buyer’s due diligence continued on.
Borescope Inspections
For years I have been preaching the importance of a borescope inspection on the engines as part of the pre-buy. Timing is crucial. Have it done before the Phase 1-4. If it reveals a significant problem, you can cancel the Phase inspections and save that money for the next deal. Chip McClure concurs. Buyers not having a borescope of the engines done prior to purchase is one of his
pet peeves. A borescope can’t get to the whole engine, but it goes where it counts the most – in the hot section. A really good technician can peek into the compressor. Anyone who balks at borescoping the engines before purchase should contrast the cost of a borescope with the repair bills for a damaged hot section. You will find them paltry by comparison. Don’t forget: One bad start can ruin an engine.
Black Death
Black Death is another problem on Chip’s list. He has seen buyers skip a pre-buy only to find this serious air conditioning problem post-purchase. It is a relatively new area of concern that I addressed in the August 2017 issue of this magazine. I field more phone calls on air conditioning (AC) than any other topic. Some mechanics are
trained in it and truly understand it. Others will tell you, frankly, that they don’t mess with AC and they should be thanked for their honesty. Far too many mechanics, trying to be helpful, will fiddle with servicing the AC or flushing the system, when they really don’t know what they are doing. Unwittingly they make things worse. The primary cause of Black Death is improper maintenance of the AC system over time. If you buy an airplane “plagued” with Black Death, the only remedy is to replace every line in the system that moves Freon. It is a very expensive job.
Structural Cracks
Pressurization cycles repeated over time eventually create cracks in the aircraft structure. Like corrosion, these cracks are cropping up more frequently as the King Air fleet ages. And yes,
22 • KING AIR MAGAZINE
AUGUST 2021