Page 20 - Volume 15 Number 11

“... almost always the left side has less friction and will migrate more.”
Our Four Friends: Power, Props, Flaps and Gear
The entire first chapter in my first book was devoted to the four friends. How tremendously useful they can be in many different King Air flying situations! What about takeoff?
Power should already be set before a suspected power loss is experienced. But is it? Now is not the time to tweak the last little bit of torque. Needless to say, reverting to the training you received in the Duchess or Seminole is incorrect for the PT6. We cannot “firewall” the power
levers without probably causing significant exceedances of torque and/or ITT limits.
If you have not yet heard of PLM – Power Lever Migration – where have you been?! The PT6 power lever linkage contains a spring that is always trying to retard the power lever toward idle. If the friction knobs are not snugged up sufficiently by clockwise rotation then you have set yourself up for a very dangerous event: A loss of power when the hand moves off the power levers to reach for the landing gear handle! What a bad time to lose power!
As I have written in previous articles, more often than not PLM is a humorous event, not a dangerous one. The pilot observes the power lever(s) sliding back, returns his hand to them, resets the desired takeoff power, and then must figure out a way to tighten the knob while still flying the airplane ... and, finally, getting the gear handle up. But, if the aft migration is not observed and if the power step of the Four Friends has already been “checked off” in the pilot’s mind, then tragedy can follow.
Each King Air is different. In some, even with the friction knobs fully backed off by turning the knobs counterclockwise to their limits, the levers do not move. In others, both snap back aggressively. Probably the most common outcome is that both move aft but the left side much more so than the right. Due to the length of the cable and its routing from the cockpit to the fuel control unit (located on the right side of both engines, making
18 • KING AIR MAGAZINE
NOVEMBER 2021