FUNCTION OF EACH VOLUME OF THE MANUAL (cont)
h. TM 11520238T8, Aviation Unit and Intermediate Troubleshooting Manual. TM 11520238T8
contains system location and description, theory of operation, ECLC index, power up/power down procedures,
MOCs, wiring interconnect diagrams, FIPs and FD/LS NOGO FIPs. The following systems are covered in this
Hoists and Winches (not applicable).
Auxiliary Power Unit.
i. TM 11520238T9, Theory of Operation.
TM 11520238T9 contains description and theory of
operation for each aircraft system. This information includes signal flow diagrams for major system functions and
explanatory text with the appropriate signal name for each input or output. This information can be used to isolate
unanticipated faults for failure symptoms or related data which do not exist.
j. TM 11520238T10, Wiring Diagrams.
TM 11520238T10 provides pointtopoint wiring for
each aircraft system. The diagrams show LRUs, cable interfaces, splices, shielding, ground studs, etc. Each cable
location and connection can be found in the wire harness location and routing diagrams. This volume also
contains connector end view diagrams and a symbol chart for the various wiring diagram symbols used.
By using these volumes, you will be able to perform inclusive troubleshooting on the
helicopter. TM 11520238T2 directs you to the appropriate volume when you know the failure symptom.
TM 11520238T1, and TM 11520238T3 through TM 11520238T8 aid you in isolating faults and
making repairs. TM 11520238T9 and TM 11520238T10 give you additional information to help you
troubleshoot the helicopter.
The following troubleshooting examples illustrate how the volumes should be used together to locate and isolate
a. Example Using TM 11520238T3 Multiplex (MUX) Read Code Volume.
(1) Assume the following failure symptom is known ADS INDICATOR LIGHTS (PILOT ANTI ICE PANEL:
PITOT ICE DET AD SNSR SWITCH SET TO OFF).
(2) Find the failure symptom in the master failure symptom index Table 21., TM 11520238T2. (The
Reference column specifies TM 91230476202, and the MOC column specifies AIR DATA SYSTEM.)
(3) Refer to TM 91230476202 and read HOW TO USE THIS MANUAL and chapter 1 to become
familiar with the manual.
(4) Go to the MOC (para 314), AIR DATA SYSTEM MAINTENANCE OPERATIONAL CHECK.
(5) Perform the MOC in paragraph 314. Step b. in the Task column instructs you to verify PITOT ICE
DET AD SNSR switch is OFF and CPG AUX/ANTIICE panel ADSS switch is set to ADSS position. The Result
column directs you to TM 11520238T3 to perform troubleshooting. Then if no fault is found, go to the