A flap slab interconnect failure on takeoff indications would present which symptom?

A flap slab interconnect failure on takeoff indications would present which symptom?

• A. Unusual forward stick force
• B. Nose wheel shimmy
• C. Rudder pedal stiffness
• D. Elevator trim flutter

Answer: (A)

The control system concept here is the flap/slab interconnect, which ties the movement of the trailing-edge flaps to the horizontal stabilizer (the slab) so that as flaps are extended for takeoff, the elevator/trim action partners with that change to maintain proper pitch and a normal control feel. If that interconnect fails, the elevator and flaps no longer move in the coordinated way they’re supposed to, so the pilot feels an abnormal change in control effort. On takeoff, this lack of coordinated movement shows up as an unusual forward stick force. In other words, the flight controls don’t feel normal—the pilot experiences an unusual push on the stick toward the nose or an unusual need to push forward to maintain the climb attitude—because the stabilizer isn’t responding with the expected nose-up moment when the flaps are extended. That abnormal control-feel is a key cue that the flap/slab interconnect isn’t functioning properly. Nose wheel shimmy relates to the landing gear on the ground, rudder pedal stiffness points to the rudder or its controls, and elevator trim flutter is a trim-system vibration issue. None of these directly describe the disrupted coordination between flap movement and the horizontal stabilizer that the interconnect failure causes, which is why they aren’t the correct symptoms.

The control system concept here is the flap/slab interconnect, which ties the movement of the trailing-edge flaps to the horizontal stabilizer (the slab) so that as flaps are extended for takeoff, the elevator/trim action partners with that change to maintain proper pitch and a normal control feel. If that interconnect fails, the elevator and flaps no longer move in the coordinated way they’re supposed to, so the pilot feels an abnormal change in control effort.

On takeoff, this lack of coordinated movement shows up as an unusual forward stick force. In other words, the flight controls don’t feel normal—the pilot experiences an unusual push on the stick toward the nose or an unusual need to push forward to maintain the climb attitude—because the stabilizer isn’t responding with the expected nose-up moment when the flaps are extended. That abnormal control-feel is a key cue that the flap/slab interconnect isn’t functioning properly.

Nose wheel shimmy relates to the landing gear on the ground, rudder pedal stiffness points to the rudder or its controls, and elevator trim flutter is a trim-system vibration issue. None of these directly describe the disrupted coordination between flap movement and the horizontal stabilizer that the interconnect failure causes, which is why they aren’t the correct symptoms.