annunciation changes only if the status has degraded to a no autoland state. A change in the autoland status from fail-operational to NO LAND 3 is inhibited. Any failure below the alert height (200 feet) which would have caused a change in the autoland status is annunciated to the flight crew by displaying a NO LAND 3 message on the PFD when the airplane has completed the landing roll and the autopilot has been disconnected.
(b)
NO LAND 3 is displayed if the autoland status has degraded from fail-operational to fail-passive. This status requires that one or more FCCs have determined a NO LAND 3 state. This state exists when a single FCC, A/P servo or outer loop sensor has failed.
(c)
NO AUTOLAND is displayed if the autoland status has degraded to the point where autoland is impossible. NO AUTOLAND state exists if two FCCs, A/P servos or outer loop sensors have failed.
(d)
These autoland status annunciations are level B messages displayed on the main EICAS and are associated with a level B aural tone.
2. Operation
_________
A. AFDS Status and Roll Mode Annunciation Signals (Fig. 6)
(1) Status Annunciation
(a)
Autopilot status messages are sent from the FCC channel when the autopilot is engaged or the flight director is on. When the autoland system is not multi-channel engaged and above 1500 feet, three status signals are supplied by the FCC. These are: 1) CMD ENGAGE 2) FLT DIR ON - CAPT 3) FLT DIR ON - F/O
(b)
During approach mode, multi-channel engaged, and below 1500 feet radio altitude, three status signals are supplied by the FCC. These are: 1) FAIL OPERATIONAL MODE - Autoland in LAND 3 status
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747-400
MAINTENANCE MANUAL
FLIGHT CONTROL COMPUTER
AFDS Status and Roll Mode Annunciation SignalsFigure 6
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747-400 MAINTENANCE MANUAL
2) FAIL PASSIVE MODE - Autoland in LAND 2 status 3) NO AUTOLAND MODE - Autoland determined impossible
(2) Roll Mode Annunciation
(a) The FCC roll mode logic determines the following armed and engaged modes: 1) LNAV Mode ARM - LNAV armed but not engaged 2) LOC MODE ARM - Approach or localizer mode armed, localizer
not captured, and no roll mode fail 3) ROLLOUT MODE ARM - Multi-channel engaged, localizer
captured, and rollout not engaged 4) HEADING HOLD MODE OPERATE - Heading hold selected 5) HEADING SELECT MODE OPERATE - Heading select engaged 6) LNAV MODE OPERATE - LNAV engaged 7) LOC MODE OPERATE - Localizer captured and rollout
disengaged 8) ROLLOUT MODE OPERATE - Rollout engaged 9) ATTITUDE HOLD MODE OPERATE - Takeoff armed and on ground,
or roll attitude armed 10) TAKEOFF MODE OPERATE (ROLL) - Takeoff armed (roll) 11) GO AROUND MODE OPERATE (ROLL) - Go-around engaged (roll) 12) LNAV LIGHT ON - LNAV engaged or LNAV armed but not engaged 13) HEADING HOLD LIGHT ON - Heading hold selected 14) LOC LIGHT ON - LOC mode armed or LOC mode operate
B. Pitch Mode Annunciation Signals (Fig. 7)
(1) Pitch Mode Annunciation
(a) The FCC pitch mode logic determines the following armed and engaged modes: 1) G/S MODE ARM - Flare mode disengaged, G/S and G/S ARM
(ANNUN) 2) FLARE MODE ARM - Multi-channel engaged and flare mode disengaged 3) TAKEOFF MODE OPERATE (PITCH) - Takeoff armed, flap limit
not exceeded, and VMO/MMO limit not exceeded 4) VERT SPD MODE OPERATE - Vertical speed armed 5) VNAV PTH OPERATE - VNAV path engaged 6) VNAV SPD OPERATE - VNAV speed engaged 7) VNAV ALT OPERATE - VNAV altitude engaged 8) ALT HOLD MODE OPERATE - Altitude select active must be
valid and delta altitude command greater than 10 feet 9) G/S MODE OPERATE - Glide slope engaged 10) FLARE MODE OPERATE - Multi-channel engaged, rollout not
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