TM     55-2840-241-23 4-5.   OH-58   T63-A-720   Engine   Compressor Health   Cheek   Procedures. a.  General  Information.  The  following  pro- cedures are to be used as a troubleshooting aid in  determining  compressor  health  when  an  en- gine fails the health check. A baseline is re- quired with this procedure. Recommend that the initial  compressor  health  check  baseline  be  performed concurrent with the establishment of the next re- quired hit baseline. New compressor health check baseline will have to be established if the N 1 indi- Do not operate engine above idle speed   with   gage   installed   or damage to gage will result. NOTE Ensure engine de-ice and bleed air heater are off prior to performing check. b. Compressor Health Check Procedure: fitting designed to accommodate a 0-30 PSI pressure gage (figures 4-5 thru 4-6). Gage needs to withstand approximately 400°F. (2) Start engine and stabilize at ground idle (62-64   percent   N 1 speed). (3) Record air pressure reading (ap- proximately   15-16   psi   for   OH-58A/C). (4) Compare gage reading with baseline reading. (a) Readings 1 to 2 psi low indicate a slightly  dirty  or  eroded  compressor. (b)  Reading  1  1/2  to  3  1/2  psi  low  indi- cate a dirty or eroded compressor. (c) Reading 3 1/2 psi or lower, check for compressor air leak or possible compressor erosion/damage c. This check should be performed on a 500 hour interval and the results annotated on the 2408-15, historical record for the aircraft, along with   and replace with a locally manufactured line with a tee gage used. Subcomponents   of   P.C   Gage   Test   Kit Item National  Stock Item Name and No Number Part Number 1 4730-00-013-6970 Elbow,  Tube  to  Hose                   3 MS27060-4C  (96906) 2 4730-00-889-2474 Adapter,  Straight  Tube                            3 MS27053-4C (96906) 3 4720-00-857-1732 Hose,   Nonmetallic                                       5 ft. MIL-H-27267-4 (81349) 4 4730-00-804-9310 Tee,  Tube                                                                  1 MS24390-4 (96906) 5 4730-00-277-5736 Coupling,  Pipe                                              4 BF-4  (16166) 6 4730-00-266-0533 Adapter,  Straight                                            1 MS35869-22 (96906) 7 6685-00-088-1548 Gage, Pressure                           1 047738 (61349) *Quantity Required for Each End- Item/System Figure 4-5. Subcomponents of PC. Gage Test Kit. 4-16.2 Change 23 cating system or the aircraft rigging has been changed or if a different gage is used. Qty Req* (1) Remove line from scroll to ezternal P C the N1 speed and the part and serial numbers of the