Good morning, I’m TSgt _ _ and I’ll be your student instructor for this lecture. Today we are going to go over the normal operation of the C-130 flap system from the pilot moving the handle all the way back to the flap moving down it’s track. We are also going to shortly cover what do if the flap system decides not to work.
The H2 aircraft is equipped with four flaps, an inboard and outboard on each wing. They are Lockheed-Fowler high lift type flaps. When the flaps are extended fully they form an angle of approximately 35 degrees with the wings. All four flaps are driven by one utility system fed hydraulic motor.
Imagine yourself preparing for landing on a normal day and the Aircraft Commander asks for 100% Flaps. The Copilot checks the aircraft speed and moves his hand down to the flap lever. As he moves it back towards 100% he passes 3 switches inside the flap quadrant. The first being the 15% switch. This changes the rudder boost system from between 1100 and 1400 psi to between 2900 and 3200 psi for landing. The next switch that the handle will activate is the 40% switch. This switch signals the GPWS computer whenever the airspeed, altitude and flap setting are not in a landing configuration. The 40% switch can be overridden by the ground proximity flap override switch which is a normal procedure during no flap landings. Next in line on our way to 100% flaps is the 70% switch. This switch activates the landing gear warning horn if the gear is in any other position but down and locked. The horn cannot be silenced until the landing gear is down and locked or the flaps are retracted back above 70%. Now that we have passed the 3 switches in the flap quadrant we finally reach the 100% position on the quadrant.
Steel cables travel from the flap quadrant on the flight deck along the hell hole, up the bulkhead and right along the hog troth until they reach flap drive control which is part of the flap drive assembly located on the aft side of the wing box.
Inside that flap drive control is a ring cam. The ring cam rotates and activates a down indication switch which energizes the Main DC powered wing…