(e)
Make sure that the EICAS advisory message HEAT P/S CAPT does not show.
(f)
Make sure that the upper left pitot probe head temperature increases.
(g)
Close 7F23, LANDING GEAR DSP & CONT ALTN circuit breaker on the P7, Overhead Circuit Breaker Panel.
(h)
Open 6D34, PROBE HEAT IND L and 6D30, PROBE HEAT PITOT L circuit breakers on the P6, Main Power Distribution Panel.
(i)
Install relay, R7433, in the P414, Left Power Distribution Center.
S 715-023
(3) Make sure that the upper left pitot probe strut heater operates:
(a)
Remove relay, R7431, from the P414, Left Power Distribution Center.
(b)
Close 6D34, PROBE HEAT IND L and 6D30, PROBE HEAT PITOT L circuit breakers on the P6, Main Power Distribution Panel.
(c)
Open 7F23, LANDING GEAR DSP & CONT ALTN circuit breaker on the P7, Overhead Circuit Breaker Panel.
(d)
Make sure that the EICAS advisory message HEAT P/S CAPT does not show.
(e)
Make sure that the upper left pitot probe strut temperature increases.
(f)
Close 7F23, LANDING GEAR DSP & CONT ALTN circuit breaker on the P7, Overhead Circuit Breaker Panel.
(g)
Open 6D34, PROBE HEAT IND L and 6D30, PROBE HEAT PITOT L circuit breakers on the P6, Main Power Distribution Panel.
(h)
Install relay, R7431, in the P414, Left Power Distribution Center.
S 715-024
(4) Make sure that the upper left pitot probe heater operates on the ground with an engine on signal:
(a)
Remove relay, R7433, from the P414 Left Power Distribution Center.
(b)
Close 6D34, PROBE HEAT IND L and 6D30, PROBE HEAT PITOT L circuit breakers on the P6, Main Power Distribution Panel.
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
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747-400 MAINTENANCE MANUAL
(c)
Set the S1 switch on the YMLA001 ENG 1 N2 speed card in the forward electrical systems card file to TEST.
(d)
Make sure that the EICAS advisory message HEAT P/S CAPT does not show.
(e)
Make sure that the upper left pitot probe head temperature increases at a lower rate.
(f)
Set the S1 switch on the YMLA001 ENG 1 N2 speed card to NORMAL.
(g)
Alternative steps to do a check of the probe heater operation: 1) Set the S1 switch on the YMLA001 ENG 1 N2 speed card to
TEST. 2) Measure the voltage at Pin B1 of Relay socket DR7431. 3) Make sure the voltage measurement is from 60 to 65 volts,
with a digital multimeter on the AC scale. 4) Set the S1 switch on the YMLA001 ENG 1 N2 speed card to NORMAL.
(h)
Open 6D34, PROBE HEAT IND L and 6D30, PROBE HEAT PITOT L circuit breakers on the P6, Main Power Distribution Panel.
(i)
Install relay, R7433, in P414 Left Power Distribution Center.
G. Lower Left Pitot Probe System Test
S 865-025
(1)
Close 6D34, PROBE HEAT IND L and 6D32, PROBE HEAT AUX PITOT L circuit breakers on the P6, Main Power Distribution Panel.
S 715-026
(2)
Make sure that the lower left pitot probe heaters operate:
(a)
Make sure that the EICAS advisory message HEAT P/S L AUX shows.
(b)
Make sure that the lower left pitot probe temperature does not increase.
(c)
Open 7F23, LANDING GEAR DSP & CONT ALTN circuit breaker on the P7, Overhead Circuit Breaker Panel.
(d)
Make sure that the EICAS advisory message HEAT P/S L AUX does not show.
(e)
Make sure that the lower left pitot probe temperature increases.
(f)
Close 7F23, LANDING GEAR DISP & CONT ALTN circuit breaker on the P7, Overhead Circuit Breaker Panel.
(g)
Make sure that the EICAS advisory message HEAT P/S L AUX shows.
S 715-027
(3) Make sure that the lower left pitot probe head heater operates:
(a)
Open 6D34, PROBE HEAT IND L and 6D32, PROBE HEAT AUX PITOT L circuit breakers on the P6, Main Power Distribution Panel.
(b) 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址:747-400 AMM 飞机维护手册 防冰和排雨 ICE AND RAIN PROTECTION(34)