Thales 421, Operation And Maintenance, Page: 142 / 256

LLZ 421
Maintenance Operation and Maintenance
ILS 420
6−2
Ed. 01.10 SOAC
6.2 PERIODIC MAINTENANCE
We recommend for a CAT. III installation to perform the maintenance activities listed in the table below
weekly, quarterly, half−yearly or yearly (more details are given in ICAO DOC 8071, Vol. I, 4th Ed.). For
other categories (CAT. II or I) the scope of activities should be defined accordingly. Besides the recom-
mended activities, the responsible authorities may define individual procedures depending on local
guide lines and requirements.
The following measuring instruments are recommended for maintenance on site:
− Desktop PC or Laptop with PC User Program (ADRACS or MCS) used for maintenance on site
− ILS test set for field measurement (e.g. PIR)
− Multimeter, frequency counter, frequency generator, spectrum analyzer (e.g. HP8561E, 30 Hz to
6.5 GHz), cables, adapters
− If non maintenance free batteries are used:
Battery maintenance equipment (acidimeter, acid syringe, areometer, thermometer, funnel). Refer
to the instructions of the manufacturer.
Ground test requirements for ILS performance CAT. III:
No. Weekly maintenance
1
2
3
4
5
6 Check system status and make a visual inspection of building equipment and antenna (6.2.1).
Check course alignment and course shift monitoring (6.2.2).
Check displacement sensitivity and displacement sensitivity monitoring (6.2.2).
Check reduction of clearance DDM deflection < 150 uA, 2F systems only (6.2.2).
Check reduction in power monitoring (6.2.2).
Check total time to shutdown, if out−of− tolerance radiation (6.2.2.1).
No. Quarterly maintenance, additional to weekly
7
8
9
10
11
12
Check Off course clearance (6.2.2).
Check settings of all parameters of both transmitters and monitoring for each parameter (6.2.2).
Check output power and power alarm (6.2.2).
Remote control system (line loss): Check LCD window ’Alerts’ for remote control alert message.
Check battery function by simulating a power failure (6.2.5).
Clean all equipment thoroughly (refer to
6.2.7).
No. Half−yearly maintenance, additional to quarterly
13a
13b
14
15
Check shutdown circuits and control logics (refer to
6.2.3
).
If the interlock function is used: Check of ECU interlock shutdown control (refer to 6.2.3.1).
Check MIT function (refer to 6.2.4, or with ECU 120571−0003 only: 6.2.4.1).
Check lead batteries including voltage check, refer to 6.3.2, 6.3.3.
No. Yearly maintenance, additional to half−yearly
16
17
18
19 Check polarization (6.2.2).
Check synthesizer difference frequency and carrier frequency, refer to 6.2.2.2 and 6.2.2.3.
Check transmitter signals with respect to further parameters like harmonics or spurious (6.2.2).
Take a complete memory readout of all possible parameters (6.2.6).
6.2.1 Damage Check
The following system parts have to be checked visually for entirety and damage:
− Shelter and equipment, fence around the station
− Antenna installation, Monitor dipole, monitor mast and cable
− Obstruction lights
− Tight fitting of all RF cable connections (internal and external)
− Tight fitting of all mechanical parts (screws and nuts)