Page 23 - May 2022

Starting the 331 is a totally different process than starting a PT6. In fact, the pilot’s left subpanel and the power quadrant are greatly changed between the A100 and B100 models. There are switches in the B100 that were never there before! Instead of Power, Propeller and Condition levers, there are Power, Speed and Fuel Cutoff & Feather levers. Because it is relatively easy to harm the engine due to improper starting procedures – and I would opine that the PT6 is much more forgiving to bad technique than the 331 – one needs to read the POH procedure thoroughly, practice it under the direction of an experienced instructor or operator, and take every care to do it properly.
For the newcomers, you need to practice the proper starting procedure thoroughly, with the battery switch off, until the steps are easy for you. It takes some coordination and practice for the fingers of the left hand to do their tasks well.
Flight Idle Fuel Flow Check
I have often discovered that the flare-for-landing characteristics of some B100s are less forgiving than desired because the Flight Idle Fuel Flow (FIFF) adjustment is set incorrectly. Perhaps in a misguided attempt to reduce engine starting temperatures, the FIFF is set too low, far below the setting desired by Beech or Garrett/Honeywell. The result is that the airplane “falls
out of the sky” when power is reduced to flight idle. Here is how you, the pilot, can determine if your airplane is meeting the proper FIFF specifications:
Begin this check at 6,000 feet pressure altitude. Configure the airplane for landing – gear down, speed levers fully forward, flaps down. Trim the aircraft for 100-105 KIAS and reduce power levers to flight idle.
Passing through 5,000 feet, check for:
A. 1,800 fpm descent rate (yes, it seems high but it’s correct!)
B. No adverse yaw
C. No Beta lights
D. Approximately 180 pph fuel flow per engine
Record the descent rate and the fuel flow that you observe, then add power and return to normal configuration.
If the FIFF needs to be adjusted, maintenance personnel should turn the adjusting screw on the rear of the fuel control unit clockwise to increase fuel flow (1 click = 2 pph). A very rough rule-of-thumb is that each 10 pph fuel flow change will make a 300 fpm rate-of-descent change. Realize that the FIFF setting cannot be verified properly without a flight test being accomplished!
MAY 2022
KING AIR MAGAZINE • 21