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SAFIR 5L
OPERATION AND ATTENDANCE MANUAL
PG 01-31
6.
DEFECTS AND TROUBLESHOOTING
General Survey
This chapter lists all the typical defects that can occur during the first actuation or during APU operation.
The schematic diagrams can be used to determine in a stepwise manner the most probable cause of a defect and the
method of eliminating it.
6.1.1.
Overview of the most common failures:
By switching on the main switch to position "RUN" and pushing "START BUTTON", the APU does not start
turning
APU is running for 2 sec. only
APU is ronning for 13÷20 sec. only
APU runs for 35 seconds only
APU not accelerate to operating speed 100 %, or after reaching the operating speed they come up for decline.
During start of the APU and main engines light signal lamp „HIGH TEMPERATURE EXHAUST GAS“ for
more than 5 seconds and rotation of the turbine decreases
APU is exessively oiled. Excessived oil consumption detected. Smoke and blasts visible in APU exhaust.
APU operation cut off due to APU rotor overspeeding
The engine do not achieve 49 % revolutions during the time of 45 sec. since the beginning of start.
