TM 1-1520-240-BD SECTION III.  BATTLE-DAMAGE REPAIRS 7-3. DEFERMENT. Scheduled maintenance as indicated   in   the   applicable   aircraft   manual   may   be deferred.  Unscheduled maintenance, such as the repair of   systems   and   subsystems   which   are   not   critical   to mission  accomplishment,  may  be  deferred  if  safety  of flight   is   not   significantly   degraded.      The   commander may    defer    combat    maintenance    and    battle-damage repair, even if doing so places operational limitations on the aircraft. 7-4. GENERAL   The   purpose   of   pneudraulic   system BDR  is  to  restore  serviceability  to  only  those  systems required to perform the mission.  The type mission to be flown  will  determine  the  system  required.    Pneudraulic system damage will normally be reported by the pilot or be   self-evident.      However,   a   full   assessment   of   all damage  is  essential  before  repair  decisions  are  made. Repair to nonessential systems should only be attempted when down time will not be increased.  These procedures    are    intended    to    provide    guidance    and suggest   approaches   to   making   essential   repairs   in   a timely manner. a. Expedient   Repairs.      Standard   repair   methods should  be  used  if  facilities,  equipment,  materials,  and experienced  personnel  are  available.    In  most  cases, standard repair methods take less time than nonstandard  repair  methods.    Some  of  the  expedient repairs   are   temporary,   while   others   are   permanent. However, it should be remembered that the objective of BDR  is  to  return  the  aircraft  to  the  flight  line  by  the speediest   means   possible   so   that   it   is   capable   of additional sorties. b. Non-detailed  Instructions.    Uncertainties  in  the battle-damage repair environment make it impossible to give     specific     repair     procedures     for     all     situations involving pneudraulic system damage.  The best repair method   will   depend   on   the   availability   of   facilities, spares,   and   the   operational   or   tactical   environment Ultimately,    the    best    method    will    depend    on    the experience  and  ingenuity  of  the  BDR  technicians.   The repair   techniques   discussed   in   this   manual   do   not include   detailed   procedures.      Therefore,   the   use   of sound   judgment   and   experience   in   the   selection   and application    of    repairs    is    of    paramount    importance. Although  these  repairs  will  restore  essential  systems  to a serviceable condition, they are intended to serve as a checklist  of  ideas.    The  repairs  are  neither  exhaustive nor mandatory. 7-5. COMPONENT   DAMAGE.       Component   damage such as hydraulic valves, will be repaired by replacement.        Serviceable    items    will    be    obtained through  normal  sources  or  cannibalization.    However, internal   repairs   will   be   attempted   when   replacement parts     are     not     available     and     technical     ability     is accessible.  Nonessential components will be isolated at the  component  or  downstream  past  the  damaged  area. Leaving existing damaged tubing installed and routing a replacement hose from the first undamaged "B" nut, can save   time.      The   procedure   is   permissible   providing existing tubing does not interfere with other operations. Secure  replacement  hose  where  it  will  not  be  damage during system operation. WARNING Substitute or repair hoses must meet system pressure and fluid requirements. 7-6. PNEUDRAULIC    SYSTEM .        When    only    one pressure   source   is   required,   other   damaged   systems maybe    isolated.        The    type    mission    required    will determine    what    systems    can    be    eliminated.        The technician and assessor will evaluate these situations. CAUTION Take care to prevent hydraulic liquid locks   whenever   a   component   has one system disconnected or isolated. A    bypass    hose    will    have    to    be installed to direct pressure from inlet port  to  outlet  port.    In  some  cases ports will have to be left open. 7-7. BDR TUBING AND HOSE REPAIR TECHNIQUES.        Of    all    battle    damage    incurred    by aircraft  pneudraulic  systems,  the  most  probable  will  be tubing and hose installation damage.  BDR to hose and tubing    installation    can    be    accomplished    in    many different  ways.  When  repairs  must  be  made,  the  most important  items  are  system  pressures,  tools  and  repair materials.    Most  aircraft  have  a  combination  of  both tubing  and  hose  installations  of  both  AN  (flared),  MS (flareless), and permaswage manufacture. Replacement  with  original  equipment  is  desirable  but not   essential,   providing   materials   are   available   and down time will not be increased. 7-8. TUBING REPAIRS. a. Manufacture.  Manufacture as per sample or template and replace damaged assembly.  This can be accomplished   using   AN   flared   assemblies   with   MS flareless installation or MS flareless assemblies with AN flared  type  installation  providing  appropriate  AN  to  MS unions are available. 7-3