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Valve Manifold Assembly
Figure 5-26.Abort aircraft-buffing aft cycle

Aviation Boatswains Mate E - Aviation theories and other practices
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NOSE-GEAR-LAUNCH CONTROL SYSTEM On ICCS ships the operation of the NGL equipment is automatic under normal operating conditions. The only controls provided are the buffer fwd and the buffer aft push buttons installed on the monitor control console, deckedge, and the central charging panel (CCP). On  non-ICCS  ships,  the  operation  of  the  NGL equipment    is    automatic    under    normal    operating conditions. Two control panels (fig. 5-23) are provided for  the  operation  of  the  NGL  system.  One  panel  is located adjacent to the catapult deckedge station for use during normal operations. A second panel is located in close proximity to the aft end of the catapult trough for emergency operations. The control panels are identical and houses a relay, terminal board, power on indicator light,  buffer  fwd  and  buffer  aft  switches  with  integral indicator lights and associated wiring. Panel selection is made by rotating a transfer switch (fig. 5-24) from its normal position to its emergency position. OPERATIONS Buffer Forward The  buffer  forward  push  button  is  used  during  an aircraft launch abort operation to move the buffer hook forward of the holdback bar so that the release element and holdback bar can be removed from the aircraft. When  the  BUFFER  FWD  push  button  is  pressed, the buffer forward solenoid (A) is energized (fig. 5-25), shifting  the  buffer  forward  solenoid  valve,  allowing medium-pressure hydraulic fluid to shift the piston of the  flow  control  valve.  When  the  piston  of  the  flow control valve shifts, fluid flow from the aft end of the buffer cylinder assembly to the gravity tank is shut off. This  causes  a  pressure  buildup  on  the  aft  end  of  the buffer cylinder assembly pistons. Since the area on the aft  side  of  the  pistons  is  larger  than  the  area  on  the forward side, the pistons, piston rods, and attached slide assembly are driven forward. Buffer Aft The  buffer  aft  push  button  is  pressed  during  an abort   operation   when   the   aircraft   holdback   bar   is connected to the buffer hook; the fluid pressure acting on  the  forward  side  of  the  buffer  pistons  will  tow  the aircraft  aft.  When  the  buffer  has  moved  back  4  to  10 inches,  the  abort  force  is  reduced  because  hydraulic pressure   is   bled   off   through   exposed   holes   in   the buffer-cylinder assembly orifice tubes. Aircraft braking is required prior to releasing the push button to hold the aircraft against its thrust load. When the NGL BUFFER AFT push button is pressed after the aircraft is removed from   the   catapult   and   the   buffer   hook   is   forward, hydraulic fluid pressure will return the pistons, piston rods,  and  slide  assembly  fully  aft.  When  the  slide assembly  is  retracted,  the  buffer  hook  returns  to  a position below deck. When the BUFFER AFT pushbutton is pressed, the buffer aft solenoid (B) is energized (fig. 5-26), shifting the   buffer   aft   solenoid   valve,   allowing   medium- pressure hydraulic fluid to shift the piston of the flow control  valve.  Medium-pressure  hydraulic  fluid  flows through  the  flow  control  valve  to  the  buffer  cylinder 5-21 ABEf0523 Figure 5-23.—Deckedge and emergency control panel. ABEf0524 Figure 5-24.—Transfer switch.







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