Page 23 - May 23

instantaneously stop the motor and the still-operating segments. The POH tells us that the stopping action will take place by the time the flaps are 3°- 6° out of sync. Since full flap extension is 35°, it means we never exceed a 20% differential.
How do we handle this split flap condition? We cannot fix the problem. Until maintenance takes place, we are stuck with the flap setting that we now have. The obvious procedural change we need to address is to determine and use a new proper VREF landing speed.
Since the flap position indicator gets its information from the right inboard flap segment only, realize that its position may not be the best measure of the overall average extension. “Eyeball” all of the segments, then make an educated guess of the proper speed, somewhere between the full flap and no flap VREFs.
Before continuing, I need to clarify a minor item. The two split flap protections that I have been discussing did not become actual microswitches until 1979. All of the 300-series use the switches since they appeared later. But the 200-series, before serial number BB-425, use a surprisingly odd design. A standard 5-amp cylindrical fuse is mounted within a fuse holder, one with the springy metal clips that hold the fuse. A clamp connects a short wire to the fuse. When the 3°- 6° separation occurs, the wire yanks the fuse out of the holding clips, shutting down the circuit. Who came up with that plan?! As funky as it seems, however, it works quite well!
How often do King Airs have split flaps? Hardly ever. Perhaps of more interest is how often does the Split Flap Protection system malfunction and leave us with inoperative flaps even though the flaps themselves are fine? I have been pleasantly surprised to find that this additional safety feature has proven to be almost 100% trouble-free. Nice!
In 1985 I had the pleasure of flying with one of my recurrent training customers to attend the Paris Air Show. His model 200 was one of the first to be modified with all of the various Raisbeck Engineering King Air STCs that existed at that time. We met James Raisbeck in Europe and used the airplane, before arriving in Paris, for some demonstration flights. A number of these flights were in Norway. Landing on some relatively short strips perched on the walls of fjords was lots of fun and certainly showed the airplane to be exceedingly capable. Upon landing for an overnight stay in Bergen our flaps did not retract.
No CBs were popped and no burned-up-flap-motor odor had been detected. I wiggled the Up limit switch and it seemed normal. Maybe split flap protection problem? In our travel kit we had a small jumper wire with alligator clips on both ends. I jumpered around the left switch – easily accessible since the flaps were down – and tried retraction again: Nothing. Moved to the right side: Success! I took off one of the control circuit wires going to the switch and screwed it on to the other
MAY 2023
KING AIR MAGAZINE • 21