Page 17 - Volume 12 Number 8

I assigned a heading and altitude and asked the owner to slow to 90 KIAS, clean. Next, approach flaps and 80 knots. All was going well, and the owner was doing a good job. “Landing gear down, full flaps, slow to 70,” were the next instructions I gave. As is my habit, I had my eyes on the flap position indicator as it started to move from Approach to Down.
Oops; that ain’t right! The needle went to about 60 percent then became a blur as it danced rapidly and when it stabilized, it was in the Up position. The owner said, “This doesn’t feel right!” as he was holding a lot of right aileron and right rudder to maintain the heading. From the cabin, the pilot yelled, “The flaps just broke!” Somewhere in that confusion I heard a snap. The flap motor circuit breaker on the aft end of the pedestal had just popped. I directed the owner to start a gradual descent. He was having no problem controlling the plane. We examined the flaps visually and confirmed that the two left segments were fully down as was the right outboard segment. But the right inboard was fully up. I knew this would be the case since the right inboard is the “master” flap because it contains both the position indicator’s transmitter and the limit switches. Since it was now Up, the Down limit switch was never activated. Hence the motor kept running, overloaded the circuit and tripped the circuit breaker (CB).
The three of us discussed the situation and it was suggested that we put the flap handle in the Up position and reset the CB. I agreed to try this good plan but also stated that it likely would not work. Why? Because the “Up” limit switch, activated by the broken segment that was now up and “telling” the motor not to run in the Up direction since it believed the flaps were already there. Handle Up, CB in – it stayed in fine – but no response.
We were now right over the airport at 5,000 feet. We were holding about 120 KIAS in our descent. We set up for a left downwind to Runway 32. There was no one else in the pattern. The owner had trimmed out the roll forces easily and was doing fine so I suggested he make the landing. He declined because he had never landed a King Air previously and asked me to take over. I did so and was pleasantly surprised that the airplane flew perfectly in this “three-down, one-up” situation. No more than half-travel of the aileron trim wheel was necessary to fly the airplane hands off. Unlike the 200- and 300-series with their
AUGUST 2018
longer wings, the 90- and 100-series have no split flap protection system since the planes were flight tested to demonstrate that any one flap section stuck up or down could easily be handled. My personal experience can now confirm this.
I carried an extra 10-15 knots into the flare since we had over 6,000 feet of runway. The landing was a nonevent and we taxied to the ramp and shut down. I asked the pilot to see if he could find any tools from anyone – it was a Saturday, so I was not very optimistic – and he left the plane to start his search.
The owner and I rolled back the aisle carpet in the cabin to start the process of gaining access to the flap gearbox, or transmission, mounted on the forward side of the rear spar beneath the floorboards. If we could disconnect the drive cables from the gearbox, we could then manually turn them to retract the other three segments and fly back to Beechcraft West for repairs, making a no-flap landing there. It had not yet dawned on me that what we had experienced was not what I was thinking. The most common reason for split flaps is that the jackscrew actuator is not operating, probably because the drive cable came loose at one of its ends. If this happens, the flap is locked in its last position.
“Hey, come look at this,” the pilot yelled to us through the open cabin door. We exited to see what he was talking
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