(2)
Test of the OBRM The ECB test the installed OBRM and ensures that the correct OBRM is installed. In case a proper OBRM is not installed on the ECB the fault output is activated.
(3)
ROM checksum evaluation The data, stored in the ECB-ROM in binary form, corresponds to a determined checksum. If the sum, evaluated during power-up, is not equal to the checksum a failure of the ROM (ECB) is declared.
(4)
RAM read/write test Every RAM location is tested in the write and read mode, with every bit high and low and with a pattern of alternating high and low bits.
(5)
Speed injection test The ECB tests the integrity of the primary and backup overspeed circuirity by stimulating the overspeed circuits with a known frequency (speed). If the measured value is not equal to the reference value a fault is detected.
(6)
Test of discretes and analog outputs The ECB energizes the fuel solenoid valve and the gearbox de-oiling valve for approx. 10msecs to determine if the outputs are open circuit or short circuit.
(7)
Oil level test The oil level test is performed using the oil temperature, evaluated by a Resistance Temperatur Device (RTD), and two reference voltages. The reference voltages are the output voltage of the RTD measured at the beginning of the test (55msecs) and the output voltage of the RTD after an energized period of 8 seconds. The oil temperature in conjunction with the delta of the two reference voltages gives a conclusion of the oil level.
NOTE : The oil level test is only performed when the A/C is on ground
____
and the air-intake flap is fully closed.
B. Manually Initiated Test It is possible to initiate a self test of the ECB via the CFDS. This self test is only released during the WATCH state while the speed is less than 7%. The self test conducts the following checks: - oil level (regardless of air intake flap position),
-speed circuits,
-engine ID,
-discrete outputs,
-ROM test,
- output test.
During the manually initiated self test a start command is not
recognized.
C. Linear Voltage Differential Tranducer (LVDT) compensation At 95% speed and prior to activation of the EGT and surge control loops, the ECB reads the position (voltage) of the actuators of the Inlet Guide Vanes (IGV) and of the Bleed Control Valve (BCV), which corresponds to the 0% position demand. These values are used to compute the 100% position (voltage) and automatically compensates for the LVDT circuirity errors.
D. Fault Detection A list fault symtoms that can occur is shown in Table 1 of Para. 7. The fault symptoms are classified as operational faults, or as Line Replaceable Unit (LRU) faults. The severity levels for the fault symptoms are also defined in Para. 7. All detected faults can be cleared and a re-start of the APU is possible by cycling the APU-MASTER switch, with the following exceptions:
-
no clearance by APU-MASTER switch cycling but APU re-start is possible . low oil level
. speed injector test faild (one primary channel).
-
no clearance by APU MASTER switch cycling and no APU re-start is possible: . back up speed injection test fails, . watch dog circuirity failure, . speed injection test (both primary channels).
With the exception of certain failures (identified by SSL=1), all shutdown faults are inhibited in flight mode. The inhibited shutdowns are not stored in the ECB nor shown on CFDS.
ENGINE IDENTIFICATION MODULE - REMOVAL/INSTALLATION
___________________________________________________ TASK 49-73-31-000-001 Engine Identification Module (8061KM) - Removal (APS 3200) WARNING : DO NOT TOUCH THE APU UNTIL IT IS SUFFICIENTLY COOL TO PREVENT BURNS
_______ WHEN YOU DO THE MAINTENANCE TASK(S).
1.
Reason for the Job
__________________
Self Explanatory
2.
Job Set-up Information
______________________
A. Fixtures, Tools, Test and Support Equipment
-------------------------------------------------------------------------------REFERENCE QTY DESIGNATION -------------------------------------------------------------------------------
No specific blanking caps
No specific circuit breaker(s) safety clip(s)
No specific access platform 2.5 m (8 ft. 2 in.)
B. Referenced Information
-------------------------------------------------------------------------------REFERENCE DESIGNATION -------------------------------------------------------------------------------
24-41-00-861-002 Energize the Aircraft Electrical Circuits from the External Power 29-00-00-864-001 Put the Related Hydraulic System in the Depressurized
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