Indicated Malfunction Probable Causes Suggested Action • Engine pressure ratio indication has high  reading error. • Engine pressure ratio indication has low  reading error due to: - Misaligned or cracked turbine discharge  probe. - Leak in turbine discharge pressure line from  probe to transmitter. - Inaccurate engine pressure ratio transmitter  or indicator. - Carbon particles collected in turbine  discharge pressure line or restrictor orifices. • Possible turbine damage and/or loss of turbine  efficiency. • If only exhaust gas temperature is high, other  parameters normal, the problem may be  thermocouple leads or instrument. • Turbine damage. • Damage in compressor section. • Engine-mounted accessory such as  constant-speed drive, generator, hydraulic  pump, etc. • Engine main bearings. • Engine bleed-air valve malfunction. • Turbine discharge pressure probe or line to  transmitter leaking. • Engine out of trim. Engine has low rpm, exhaust  gas temperature, and fuel  flow when set to expected  engine pressure ratio. Engine has high rpm, exhaust  gas temperature, and fuel  flow when set to expect  engine pressure ration. Engine has high exhaust gas  temperature, low rpm, and  high fuel flow at all engine  pressure ratio settings. NOTE: Engines with damage  in turbine section may have  tendency to hang up during  starting. Engine vibrates throughout  rpm range, but indicated  amplitude reduces as rpm is  reduced. Engine vibrates at high rpm  and fuel flow when compared  to constant engine pressure  ratio. Engine vibrates throughout  rpm range, but is more  pronounced in cruise or idle  rpm range. No change in power setting  parameters, but oil  temperature high. Engine has higher than  normal exhaust gas  temperature during takeoff,  climb, and cruise. Rpm and  fuel flow higher than normal. Engine has high exhaust gas  temperature at target engine  pressure ratio for takeoff. • Check inlet pressure line from probe to  transmitter for leaks. • Check engine pressure ratio transmitter and  indicator for accuracy. • Check probe condition. • Pressure-test turbine discharge pressure line  for leaks. • Check engine pressure ratio transmitter and  indicator for accuracy. • Confirm indication of turbine damage by: - Checking engine coast-down for abnormal  noise and reduced time. - Visually inspect turbine area with strong light. • Re-calibrate exhaust gas temperature  instrumentation. • Check turbine as outlined in preceding item. • Check compressor section for damage. • Check each component in turn. • Check scavenge oil filters and magnetic plugs. • Check operation of bleed valve. • Check condition of probe and pressure line to  transmitter. • Check engine with jetcal. Re-trim as desired. Figure 10-75.  Troubleshooting turbojet engines.  10-61