[3] Figure 40-3 illustrates an example of the autoland. After selecting APP and engaging the second autopilot to CMD, an automatic transition is made from ILS approach through autoland. The LNAV and VNAV are still in control.
Fig. 40-3 autoland
A. Initial conditions -------- with LNAV and VNAN engaged, the FMC provides guidance to the A/P and A/T to command approach altitude at 150 knots on a heading for localizer intercept.
B. Approach preparations -------- Tune both VHF NAV receivers to the inbound ILS frequency. Select the inbound course on both course displays. Press the APP mode switch on the MCP and engage the second A/P to CMD.
C. Localizer mode -------- Mode logic in the A/P determines the optimum capture point relative to the localizer beam. At localizer capture, LNAV is disengaged and the LNAV mode switch extinguishes.
D. Glide slope mode ------ The glide slope capture point is approximately 0.5 dot of deviation. The A/P and F/D commands a descent to make a smooth transition to glide slope.
E. Approach on course ------- Approach on course (AOC) occurs at 1500 feet radio altitude.
F. Approach on course plus ten seconds -------- Ten seconds after AOC, the second A/P is engaged in both roll and pitch channels.
G. Radio altitude FCC internal discretes ------ The airplane should be stabilized on the ILS in the landing configuration before reaching 800 feet. The second A/P must be engaged in CMD at this point. If a disconnect occurs above 800 feet, both channels can be re-engaged. Below 800 feet only a single channel can be re-engaged.
H. Landing ------- At 50 feet, FLARE occurs. The A/P controls the airplane to reduce vertical speed to -2.5 feet per second at touchdown. The flight director commands are biased off. At 27 feet R/A or 2.5 seconds after flare (whichever comes first), the A/T retards the throttles and A/T annunciates RETARD.
I. Touchdown ------- Press the A/P disengage switch on the control wheel. The A/P red warning light on the FMA flashes and an aural warning is heard. Press either control wheel disconnect switch or either warning light assembly to reset the warning. At squat, the A/T transfers to ARM. At squat plus 2 seconds, the A/T disconnect. There is no warning for touchdown A/T disconnect. When on ground and the ground speed is reduced to less than 20 knots, all annunciation is off.
READING MATERIAL
QUESTIONS TO LESSON 40 READING MATERIAL
1. What failures are recorded?
2. What does the inflight fault history include?
3. What is the priority order of flight deck effects?
4. A failure may cause more than one flight deck effect. Is only the highest priority flight deck effect recorded?
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本文链接地址：第31课 大气数据系统 LESSON 31 AIR DATA SYSTEM(45)
