.
balance fuel if required
.
verify rudder trim is zero
.
ensure the autopilot is engaged in HDG SEL or HDG HOLD and
stabilized for at least 30 seconds
.
trim the rudder in the direction corresponding to the down (low) side of
the control wheel until the bank indicates level (no bank angle indicated
on the bank pointer). Apply rudder trim incrementally, allowing the bank
to stabilize after each trim input. Large trim inputs are more difficult to
coordinate. The airplane is properly trimmed when the bank angle on the
bank pointer indicates zero. If the airplane is properly rigged, the control
wheel should indicate approximately level. The resultant control wheel
condition indicates the true aileron (roll) trim of the airplane being used
by the autopilot.
After completing the alternate rudder trim technique, if the autopilot is disengaged the airplane may have a rolling tendency. Hold the wings level using the sky pointer as reference. Trim out any control wheel forces using the aileron trim switches. If properly trimmed, the airplane holds a constant heading and the aileron trim reading on the wheel/column agrees with what was seen while the autopilot was engaged. Aileron trim inputs require additional time and should be accomplished prior to final approach.
Flight Management Computer(s)/CDUs
The Flight Management System provides the crew with navigation and performance information that can result in a significant crew workload reduction. This workload reduction is fully realized when the system is operated as intended, including proper preflight and timely changes in flight. FMC guidance must always be monitored after any in flight changes. In the event flight plan changes occur at inopportune times or in areas of high traffic density, the crew should not hesitate to revert to modes other than LNAV/VNAV.
During preflight, all flight plan or performance related FMC CDU entries made by one pilot must be verified by the other pilot. In flight FMC CDU changes should be made by the pilot not flying and executed only after confirmation by the pilot flying.
FMC Route Verification Techniques
After entering the route into the FMC, the crew should verify that the entered route is correct. There are several techniques that may be used to accomplish this. The crew should always compare:
.
the filed flight plan with the airways and waypoints entered on the
ROUTE pages
.
the computer flight plan total distance and estimated fuel remaining with
the FMC-calculated distance to destination and the calculated fuel
remaining at destination on the PROGRESS page.
For longer flights and flights that are planned to transit oceanic airspace, the crew should cross-check each leg on the LEGS page with the computer flight plan to ensure that the waypoints, magnetic or true tracks, and distances between waypoints match.
If there is a discrepancy noted in any of the above, correct the LEGS page to match the filed flight plan legs. A cross check of the map display using the plan mode may also assist in verification of the flight plan.
Required Navigation Performance (RNP) Operations
RNP defines navigation accuracy required for a specified route or terminal area procedure. This accuracy is specified in NM (for example RNP 0.3 where the accuracy required is "within 0.3 NM"). RNP values are usually smaller for terminal area procedures (SIDs, STARs, approach transitions, and approaches) than enroute procedures. Small RNP values can require navigation accuracy that is more precise than current VOR/ADF navigation, allowing lower weather minima for departures and/or approaches.
The FMC can use one of the following as the displayed RNP:
.
default RNP - FMC default values are set by the FMC and are displayed if
no RNP is available from the navigation data base.
.
manually entered RNP - A manually entered RNP remains until changed
or deleted. The crew may need to make a manual RNP entry if the RNP
for the route or procedure is incorrect.
Note: Future navigation data bases will be capable of providing an RNP for each route or procedure.
Setting a RNP smaller than what is specified for the procedure, airspace, or route, may cause inappropriate crew alerts. Operators should select FMC default values that meet the requirements of their route structure. However, AFM requirements may specify RNPs for certain approaches. (For example, RNP 0.3 is required for GPS approaches).
The FMC calculates its Actual Navigation Performance (ANP) and displays this as ACTUAL. ACTUAL is displayed in NM and specifies the accuracy associated with the FMC position. This accuracy is based on a 95% probability that the FMC position is within the ANP value. This calculation is based on the source of updating (GPS, DME-DME, VOR-DME, LOC-GPS, LOC-DME-DME, LOC VOR-DME, or LOC) and the time since the last update to the FMC position from one of these sources. When the FMC is not updating from one of these sources the indicated mode is INERTIAL. ANP is smaller with more accurate updating sources. GPS updating provides the smallest ANP and the highest position accuracy while INERTIAL updating provides the highest ANP value and the lowest position accuracy.
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本文链接地址：757 Flight Crew Training Manual 机组训练手册(16)
