Page 14 - Dec 23

MAINTENANCE TIP
Legacy King Airs and the IPC
by Dean Benedict
Adirector of maintenance from Alaska with several King Air B100s called me not long ago. The most recent addition to his fleet had a pressurization problem that would not resolve. The system tested fine on the ground, but there was no pressurization in the air. He had researched the part number of the flow pack in the IPC (Illustrated Parts Catalog), ordered exchange units and installed them. The pressurization checked good on the ground but was “inop” in the air.
I asked him if he exchanged the pneumostats as well, and he had not. That was my first suggestion. My cardinal rule No. 1 with pneumatic flow packs is: Whenever exchanging a flow pack, exchange the pneumostat at the same time.
Assuming that the first set of flow packs were out-of- box failures, he sent them back and ordered an exchange
flow pack and pneumostat for each side. He received the parts, installed them in the aircraft, but again, there was no change. Pressurization checked good on the ground but was non-existent in the air.
He called once more, and I admit I was a little bit stymied. I had to dig deeper. I had him make sure all the various components in the pressurization system were
12 • KING AIR MAGAZINE
DECEMBER 2023
An upgrade or modification for your King Air, such as new props, requires an STC. The obliga- tory maintenance for that modification is found in the Instructions for Continued Airworthiness (ICA).