.
exiting the APP mode requires initiating a go-around or disconnecting the
autopilot and turning off the flight directors.
When in altitude hold at MDA(H) and prior to commencing the circling maneuver, set the missed approach altitude.
Initiating the turn to base leg, select landing flaps and begin decelerating to the approach speed plus wind correction. To avoid overshooting final approach course, adjust the turn to final to initially aim at the inside edge of the runway threshold. Timely speed reduction also reduces turning radius to the runway. Complete the landing checklist. Do not descend below MDA(H) until intercepting the visual profile to the landing runway.
Leaving MDA(H), disengage the autopilot and disconnect the autothrottle. After intercepting the visual profile, cycle both F/D to OFF, and select the PNF F/D to ON. This eliminates unwanted commands for the PF and allows continued F/D guidance for the PNF in the event of a go-around when pitch or roll mode is changed. Complete the landing.
Note: If a go-around is selected with F/D switches off, the F/D commands disappear when the first pitch or roll mode is selected or engaged.
Obstruction Clearance
Obstruction clearance areas during the circling approach are depicted in the following figure. Distances are determined by aircraft approach category. Adjust airplane heading and timing so that the airplane ground track does not exceed the obstruction clearance distance from the runway at any time during the circling approach.
Circling Approach - One Engine Inoperative
If a circling approach is anticipated, maintain gear down, flaps 20 and a minimum of VREF 20 + wind correction while circling. Do not descend below MDA(H) until intercepting the visual profile.
Under some flight conditions such as high temperatures, high pressure altitudes, and high airplane weight, limit thrust may be required to maintain level flight with the gear down and flaps 20. When these conditions are encountered consider retracting the landing gear for the circling portion of the approach after the descent to MDA(H). The GPWS gear override switch may be used to prevent nuisance warnings.
Missed Approach - Circling
If a missed approach is required at any time while circling, make a climbing turn in the shortest direction toward the landing runway. This may result in a turn greater than 180° to intercept the missed approach course. Maintain the missed approach flap setting until close-in maneuvering is completed.
Different patterns may be required to become established on the prescribed missed approach course. This depends on airplane position at the time the missed approach is started. The following figure illustrates the maneuvering that may be required. This ensures the airplane remains within the circling and missed approach obstruction clearance areas.
In the event that a missed approach must be accomplished from below the MDA(H), consideration should be given to selecting a flight path which assures safe obstacle clearance until reaching an appropriate altitude on the specified missed approach path.
Refer to Missed Approach/Go-Around - All Approaches, this chapter.
Copyright . The Boeing Company. See title page for details.
October 31, 2003 FCT 757 (TM) 5.51
Visual Approach - General
The recommended landing approach path is approximately 2 1/2° to 3°. Once the final approach is established, the airplane configuration remains fixed and only small adjustments to the glide path, approach speed, and trim are necessary. This results in the same approach profile under all conditions.
Thrust
Engine thrust and elevators are the primary means to control attitude and rate of descent. Adjust thrust slowly using small increments. Sudden large thrust changes make airplane control more difficult and are indicative of an unstable approach. No large changes should be necessary except when performing a go-around. Large thrust changes are not required when extending landing gear or flaps on downwind and base leg. A thrust increase may be required when stabilizing on speed on final approach.
Downwind and Base Leg
Fly at an altitude of 1500 feet above the runway elevation and enter downwind with flaps 5 at flaps 5 maneuvering speed. Maintain a track parallel to the landing runway approximately 2 NM abeam.
Prior to turning base leg, extend the landing gear, select flaps 20, arm the speedbrake, and slow to flaps 20 maneuvering speed or approach speed plus wind correction if landing at flaps 20. If the approach pattern must be extended, delay lowering gear and selecting flaps 20 until approaching the normal visual approach profile. Turning base leg, adjust thrust as required while descending at approximately 600-700 fpm.
Extend landing flaps prior to turning final. Allow the speed to decrease to the proper final approach speed and trim the airplane. Complete the Landing checklist. When established in the landing configuration, maneuvering to final approach may be accomplished at final approach speed (VREF + wind correction).
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本文链接地址：757 Flight Crew Training Manual 机组训练手册(64)
