(k)
High Oil Temperature Shutdown A shutdown occurs if the HOT signal is present and the speed is greater than 95%, or cooldown is active with the speed greater than 50%. The HOT shutdown is delayed by 10 seconds.
(l)
No Acceleration Shutdown The ECB detects a slow start and shuts down the APU if the start initialization is complete and the
-
Acceleration is less than 0.5 %/s for 60 seconds,
or
-
Acceleration is less than 0.2 %/s for 30 seconds,
or
-
Acceleration is less than 0.1 %/s for 15 seconds and APU is in light-off condition (adequate rise of EGT).
(m)
Not Applicable
(n)
Reverse Flow Shutdown A reverse flow shutdown occurs when speed is greater than 50 percent, LCIT is not failed, and one of two following sets of condition are met:
1 Two occurrences of Surge condition where both occurrences are
_
within 7.5 seconds, but at least 2.5 seconds apart.
2 Two occurrences of LCIT greater than 350F for 0.1 seconds
_ where both occurences are within 7.5 seconds, but at least 2.5 seconds apart (there may be intermediate occurrences within the 2.5 seconds).
(o)
Start Time Exceeded Shutdown The start time exceeded shutdown occurs when the main start contactor is commanded but the APU speed is less than 7 % for at least 30 seconds.
(p)
Clogged Oil Filter Shutdown The ECB shuts down the APU after 5 seconds if:
-a clogged oil-filter signal is triggered and
-
the oil temperature is higher than 100 DEG.F (37.77 DEG.C) and
-
the APU is on governed speed condition (> 95 % rpm). This shutdown is inhibited during flight (TSO/JAR).
(q)
Main Power Interrupt Shutdown On every APU shutdown (normal or protective), the ECB sets a flag that a regular shutdown sequence has occured. On the next power-up the ECB checks this flag. If it is not set, it indicates that the previous APU run was terminated by a power loss, and the ECB records a loss of DC power shutdown. Power interrupts shorter than 500 msec will not cause a shutdown if the interrupt supply is available, without interrupt supply the limit is 200 msec.
(r)
IGV Shutdown There are two conditions for an IGV shutdown:
1 The IGV command and position differ by more than 10 degrees
_ for 5 seconds when the speed is between 50 and 95%, or
2 The speed is above 95% and the IGV position goes 2 degrees
_
below RTL for 5 seconds.
R **ON A/C 001-003, 051-099, 401-499,
8. BITE Test
_________
A. BITE Test
The BITE tests the three subsequent BITE modes:
-
the Power Up Test (PUT),
-
the In Operation Test (IOT),
-
the self test if started from the MCDU.
(1) Power-Up Test (PUT) The PUT starts if the subsequent signals are available:
-
the power up initialization is complete and
-
the APU speed is below 7 % or
-
the start signal received for more than 60 seconds.
During the PUT the drivers and the loads are tested for open and short. The switches are tested for thier position and the sensor signals are compared to thier limits.
(2)
In Operation Test (IOT) The IOT tests all LRUs which are necessary for the APU operation. The IOT starts after the PUT.
(3)
Self Test The self test is similar to the power-up test. It is opational when:
-
the test is manual started from the MCDU,
-
the APU speed is less than 7%.
(4)
Built In Test Equipment (BITE) For the indication of the report and test pages on the MCDU refer to the chapter 49-73-00 Analyzers.
**ON A/C 001-003, 051-062,
B. Alternate Values for Failed Sensors
(1)
The ECB 59KD programs alternate values for certain failed LRUs. These are identified in the PUT or during the APU IOT. The LRU failures and the alternate actions are listed in Table 3. There is a time delay period between the failure of the LRU and program of the alternate value. The ECB uses the last value indicated before LRU failure.
(2)
Table 3 Alternate Values List for Failed Sensors
-------------------------------------------------------------------------------
Failed -------------------------- Action-----------------------------------------------------
1. P2 Sensor * 1. On ground: Program P2 = 0.94 bar (13.66 psia)
2. In flight:
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