(2)
With the FPV switch ON and the AFDS FD switch ON, the FPV display symbol appears and the aircraft reference FD command bars appear.
(3)
With the FPV switch OFF and the AFDS FD switch ON, the existing aircraft reference FD command bars are displayed.
(4)
On approach, with the FPV symbol and the rising runway displayed, the FPV symbol disappears at 200 feet, radio altitude.
(5)
On go-around, if the aircraft descends below 200 feet, radio altitude, while the rising runway symbol is displayed, the FPV symbol disappears until the aircraft ascends to more than 200 feet, radio altitude.
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(6)
On landing rollout, the rising runway symbol blanks and the FPV, if selected earlier, reappears.
(7)
At takeoff with the localizer selected, the rising runway symbol is blanked, the radio altitude appears at the bottom of the PFD, and the FPV symbol is available.
D. EICAS display
(1) The EICAS displays are located on the center instrument panel,P2-2. The main EICAS display provides IRS caution, advisory and memo messages. The auxiliary EICAS display provides IRS status messages.
(a) The IRS - related EICAS messages are as follows: ~............................................................................... | MESSAGES | LEVEL | SIGNIFICANCE | ................................................................................. | ATTITUDE | CAUTION/STATUS | CAPT & F/O attitudes disagree| ................................................................................. | TRACK | ADVISORY/STATUS | CAPT & F/O tracks disagree | ................................................................................. | HEADING | ADVISORY/STATUS | CAPT & F/O headings disagree | ................................................................................. | IRS LEFT (RIGHT, CENTER) | ADVISORY/STATUS | L (R, C) IRU system fault | ................................................................................. | >IRS DC LEFT (RIGHT, CENTER) | ADVISORY/STATUS | L (R, C) IRU DC failure | ................................................................................. | >IRS AC LEFT (RIGHT, CENTER) | ADVISORY/STATUS | L (R, C) IRU AC failure | ................................................................................. | SOURCE SEL IRS | ADVISORY/STATUS | Capt & F/O using same IRU | ................................................................................. | IRS MOTION | ADVISORY | Motion detected during align | ................................................................................. | IRS ALIGN MODE L (R,C) | MEMO | L (R, C) IRU is in ALIGN mode| 2..............................….................…..............................1
E. IRS Resistor Modules and IRS Diode Modules.
(1) Three resistor modules (M4300D, M4301D, M4302D) mate with wire interface unit (WIU) M4160 on Shelf E1-6 in the Main Equipment Center, one for each IRU (L, C, R) on the airplane. Each (of 3) 47-ohm resistors in a module terminates one of the three analog discrete lines (DC FAIL, ALIGN, ON DC) to the IRS System ground. Each resistor prevents a false alarm during wraparound test of the applicable analog discrete.
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(2) One diode in module M4163D is installed between each IRU and the IRS ON DC relay to prevent spiking when that relay functions and turns off the "IRS ON BATTERY" horn and annunicator lights after 9 to 11 seconds of operation when APL ON GND is true (the AIR/GND relay is energized).
8. Operation
_________
A. Functional Description (Fig. 8 and Fig. 9)
(1) IRS ALIGN mode
(a)
In the alignment mode, the IRS ALIGN MODE message(s) appears on the upper EICAS display, the IRU reference axis is aligned to the local vertical, initial velocities are set to zero and the IRU calculates latitude and true heading by measuring the earth's rotation rate.
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