Sem título

MLG EXTENSION AND RETRACTION

1. UPLOCK MECHANISM AND ACTUATOR

   • PURPOSE
   • LOCATION
     • There are two MLG uplock mechanisms, one for each MLG, on the ceiling on the outboard edges of the main landing gear wheel well.
       • Why use a an over-center lock?
   • PHYSICAL DESCRIPTION
     • HAS THESE COMPONENTS
       • - Springs (2)
       • Uplock actuator.
       • - Uplock hook
   • FUNCTIONAL DESCRIPTION
   • TRAINING POINT

2. -- DOWNLOCK MECHANISM AND ACTUATOR

   • PURPOSE
   • LOCATION
     • Why use a an over-center lock?
   • What is the function of the has a restrictor relief valve at the body?
     • On what pressure the relief valve open?
   • The downlock actuator has a restrictor check valve. What is the function of that relief valve?
   • TRAINING POINT
   • PHISICAL DESCRIPTION

3. MAIN LANDING GEAR ACTUATOR

   • PURPOSE
   • LOCATION
     • The MLG actuator is on the wing structure outboard of the MLG shock strut. One end attaches to a beam hanger and the walking beam pivot
   • PHYSICAL DESCRIPTION
     • has an internal restrictor.
       • What is the function of this restrictor?
     • what prevent the incorrect function of the hydraulic hoses?
   • FUNCTIONAL DESCRIPTION
   • Training Information Point

4. TRANSFER CYLINDER

   • PURPOSE
   • LOCATION
     • The transfer cylinder is on the rear spar of the left and right wings.
   • FUNCTIONAL DESCRIPTION

5. FRANGIBLE FITTING

   • PURPOSE
   • LOCATION
   • PHYSICAL DESCRIPTION
     • The frangible fitting operates during this sequence
       • - A section of tread comes off from a main landing gear tire but not fully
         • - Landing gear starts to retract
           • - Gear retract braking has a fault and does not stop the wheel before it moves into the wheel well
             • - The section of tread removes the lever from the frangible fitting
               • - Frangible fitting opens
                 • - Up pressure is removed from the main landing gear actuator
                   • - Main landing gear that has the damaged tire stops retraction and moves to the extended position
                     • - Flow limiter in the up pressure line keeps the flow limit to 8 gpm (30 lpm) from the volume fuse to the frangible fitting and MLG actuator
                       • - Volume fuse in the up pressure line closes when the hydraulic flow through the frangible fitting increases to 180-250 cubic inches (3-4 liters); this stops the loss of fluid from the hydraulic system.