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2.4
Lens heating optional device
The LHA unit of LED PAPI 66 system can be equipped with optional lens heaters. The heater is controlled by a
microprocessor system to delete any problem caused by repeated and close on-off cycles and to optimise the
relative consumption.
The heater is always activated at full power for 25 minutes after the unit is powered on. Subsequently it remains
powered at low power to keep the lens warm at about 5 ° above ambient temperature.
In any case, if the lens temperature exceeds a certain threshold, the heater is deactivated.
2.5
Tilt switch optional device
The effectiveness of the LED PAPI 66 system is determined by the correct inclination of the light beams of the
LHA units installed. If a LHA unit loses the alignment of the correct inclination, can provide incorrect indications to
the pilot approaching.
Each LHA unit can be equipped with a tilt switch optional device of the LHA unit and, if this deviates by the correct
inclination set during installation, the whole LHA units system is deactivated (with a delay of 10-30 seconds, to
avoid detection mistakes due to temporary external conditions, such as wind or vibrations).
The PAPI system is designed to operate in fail-safe mode: when the LHA units are equipped with tilt switch device,
the system becomes operational only if all LHA units are correctly inclined.
2.6
Tilt switch optional device (mercury-free)
The LED PAPI 66 system can be equipped with tilt switch optional device mercury-free type (for applications in
areas in which mercury is listed among the substances subject to restrictions). The operation of these components
is similar to the one already described in the paragraph related to the standard tilt.
2.7
Behaviour in case of fault
Below are listed the possible types of faults and the behaviour of the failed unit and of other units of the system
in the various cases:
●
Tilt error: the tilt switch device detects the misalignment of the LHA unit with respect to the inclination set
during installation. All the LHA units in service of the PAPI system switch off after about 10-30 seconds.
●
LED module fault. All the LHA units in service of the PAPI system switch off after a few seconds.
●
Fault of the unit supply system: an internal fault occurs or the power supply is disconnected. The LHA failed
unit switches off immediately (or does not switch on) and the remaining LHA units in service of the PAPI
system switch off after a few seconds.
2.8
Optional monitoring device
The LED PAPI 66 LHA unit can be equipped with an optional device for monitoring its operating status remotely.
It is an internal relay with contact normally open. The contact is externally made available through a cable with
L-823 Style 6 plug.
The status of the contact reports the information on the operating status of the unit:
●
Closed contact: LHA unit in operating condition.
●
Open contact: LHA unit in fault condition or disconnected.
The relay opens the contact in case of fault, as described in the previous paragraph: tilt error, LED module fault,
supply system fault.
Only the monitoring contact of the faulty (or not powered) unit is open, while the unit in
operating condition switch off their own LEDs after a few seconds and keep the contact of
the relay closed: in this way the faulty unit can be identified by an external monitoring system
ILCMS (Individual Lamp Control and Monitoring System).
UT-MT-0972_1.0_19-09-2022 (EN)
Use and Maintenance Manual
LED PAPI 66
17
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