For those who are interested in the basics behind a330 probe heating
Monitoring
The PHC monitors heating of the static probes, AOA sensor, pitot probes and TAT sensor. Current detection with a preset threshold is provided for monitoring purposes.
Low heating or overcurrent or heating loss triggers a warning.
Monitoring of the TAT sensors is inhibited on the ground.
A monitoring system activates a warning when heating is incorrect. Warning is triggered as follows:
(a)
For pitot probe
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in flight when the current I is lower than 0.9A or greater than 6A
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on ground when the current I is lower than 0.4A or greater than 4A.
(b)
For TAT sensor
When the current I is lower than 0.8A or greater than 4A.
(c)
For AOA sensor
When the current I is lower than 0.12A or greater than 5A.
(d)
For L and R static probes
When the current is lower than 1.3A or greater than 4A.
The PHC serves to:
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identify the faulty element(s),
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memorize the faulty element.
(2)
Indication
The PHC continuously emits signals via the ARINC 429 bus (low speed).
A discrete output (one per probe) informs the ADIRU of associated probe channel of the heating fault. Then, the ADIRU informs the Flight Warning Computer (FWC).