Page 22 - March24

Within its capabilities, the pressurization controller will keep the cabin at the set altitude the best it can.
time for landing gear extension and maybe, if it’s not overly turbulent, approach flaps too. Remember that the maximum allowable load factor limit is reduced when flaps are extended.
Even the relatively small portion of air that is bled from the engine’s compressor for cabin pressurization and heating in a King Air typically causes the engine to run about a 10 to 20 degrees hotter ITT than if the bleed air were shut off and allowed to remain in the engine. That explains why leaving the bleed air valve switches closed sometimes allows more takeoff power to be achieved.
Outflow
The pressurization control system is made by Honeywell Aerospace. Honeywell is the name that has survived from a long line of com- pany acquisitions and mergers. The control system we use evolved from the very first installations used on
vertical velocity indicator (VVI), more than torque or fuel flow, when I reduce power significantly. You may need to push the power levers back
up a bit to keep supplying enough inflow to prevent the cabin from ascending. On the other hand, if you need to come down steeper, it’s
Break through with Ice Shield®
Wing De-Ice Boots
Inflow
The flow packs attempt to provide constant air mass flow regardless of altitude, outside air temperature, or compressor speed (N1 or Ng). If compressor speed is too low, however, the flow cannot keep supplying the pounds of air that it should ... the air pump isn’t turning fast enough. A quick and unscientific
22 check of your inflow and outflow is
29
High Quality, Reliable Wing De-Ice Boot. Co an authorized Distributor today for purchase!
an ATC request or to keep the speed
this: Can you maintain maximum
∆P with both power levers pulled 6 back far enough to just trigger the landing gear warning horn? If the answer is no, then you can be sure that your air inflow is too low (weak or dead flow pack) or your air outflow is too high (excessive leaks)
IceShield.com • 800-767-6899 • info@iceshield.com
or
a
c
om
ination of both.
n
t
a
c
t
b
As you reduce power aggressively
for a descent – either to comply with
down due to turbulence – you may
observe the cabin starting to climb.
In fact, I tend to watch the cabin’s
20 • KING AIR MAGAZINE
MARCH 2024