TM 1-1500-204-23-1 Figure 8-15.  Simplex Fuel Nozzle a.    General  Procedures.     The  following  procedures shall be adhered to during turbine engine maintenance. (1)   Mark location of all attaching support brackets, clamps,   and   clips   prior   to   removing   lines,   tubes,   or conduit  to  facilitate  reassembly  with  a  felt  tip  marker Use ink conforming to Federal Specification TT-1-544. (2)    Use  new  O-rings,  packing  rings,  cotter  pins, lockpins, gaskets, and washers. (3)  Apply lubricating grease, MIL-G-4343, on all O- rings prior to installation. (4)    Apply  thread  compound,  MIL-A-13881,  to  all threaded parts attached to the hot section. (5)    When  gears  are  replaced,  examine  for  pattern wear and backlash. b.  Health Indication Test.   The Health Indication Test (HIT)  is  the  method  by  which  the  aviator  In  day-to-day flying  monitors  the  aircraft  engine  condition.    This  is accomplished by the aviator selecting an N1 speed (%) predicated   upon   the   existing   Free   Air   Temperature (FAT).    The  interstate  Turbine  Temperature  (ITT)  must then relate to a predicated value (Baseline ITT) within a certain  tolerance.    ITT  variation  from  baseline  values are    logged    by    the    aviator    in    accordance    with    the applicable   maintenance   manual   This   log,   part   of   the engine  records,  is  available  to  the  maintenance  officer as   an   aid   In   monitoring   performance   trends   and   in troubleshooting When the difference between a recorded  ITT  and  the  baseline  ITT  is  20 °C  (68 °F)  or greater the aviator will make an entry on DA Form 2408- 13  to  notify  the  maintenance  officer.    A  difference  of 30C (86°F) or greater is cause for grounding the aircraft until    troubleshooting    determines    the    cause    of    the excessive ITT.  New ITT baseline values for HIT should be    established    after    performing    a    baseline    engine performance  check.    A  new  engine  performance  check should be made when an engine Is changed, when the fuel control unit is adjusted or replaced, or when repairs are made to the engine hot section. c.    Hot  Start  Inspection.     A   hot   start   occurs   when exhaust    gas    temperature    exceeds    normal    starting temperature limit. NOTE A  hot  start  may  be  expected  when  a greater-than-normal starting fuel flow Is observed just as the power lever is moved Into the IDLE position. d.  Turbine Engine Analysis Check (TEAC).  A normal Turbine Engine Analysis Check (TEAC) is performed for comparison  of  normal  TEAC  data  with  baseline  data. This will confirm whether or not performance degradation   has   occurred   and   to   what   degree.      In addition,  TEAC  data  can  be  an  aid  in  determining  the cause    of    the    performance    loss    (Refer    to    TEAC troubleshooting).    A  normal  TEAC  shall  be  performed whenever  installed  engine  performance  degradation  Is suspected    or    as    part    of    a    general    test    flight    (if applicable). e.  Foreign Object Damage Inspection.   Most damage incurred   by   the   engine   is   the   result   of   ingestion   of foreign   objects   Although   screens   are   provided   in   the lower    aft    cowling    section    and    around    the    engine compressor inlet case to prevent entry of larger objects, sand and grit will enter and cause compressor damage. The  resultant  damage  will  be  in  the  form  of  nicks  or scratches  on  the  compressor  blades.    Such  a  nick  or scratch    can    cause    fatigue    failure    hours    later,    with disastrous effects to the entire engine. CAUTION When  maintenance  is  performed  on the    engine,    every    effort    shall    be made   to   retrieve   any   object   (wire, rivets,   nuts,   screws,   etc.)   dropped through the compressor inlet screen or  into  the  cowling,  even  if  engine disassembly Is required.  Damage to the engine may otherwise result. 8-13