Turning Radius
The wing tip of the 757-200 and the tail of the 757-300 (not shown in the drawing below) swing the largest arcs while turning and determine the minimum obstruction clearance path. All other portions of the airplane structure remain within these arcs.
CAUTION: Do not attempt to make a turn away from an obstacle within (15 feet/4.6 m) of the wing tip for the 757-200, or (16 feet/4.9 m) for the 757-300, or within (26 feet/7.9 m) of the nose for the 757-200, or (20 feet/6.1 m) for the 757-300.
Visual Cues and Techniques for Turning while Taxiing
The following visual cues assume the pilot’s seat is adjusted for proper eye position. The following techniques also assume a typical taxiway width. Since there are many combinations of turn angles, taxiway widths, fillet sizes and taxiway surface conditions, pilot judgment must dictate the point of turn initiation and the amount of nose wheel tiller required for each turn. Except for turns less than approximately 30°, speed should be 10 knots or less prior to turn entry. For all turns, keep in mind the main gear are located behind the nose wheels, which causes them to track inside the nose wheels during turns. The pilot position forward of the nose wheel and main gear is depicted in the table below.
Model Pilot Seat Position Pilot Seat Position
(forward of nose gear) (forward of main gear)
feet (meters) feet (meters)
757 - 200 12 (3.7) 72 (22)
757 - 300 12 (3.7) 85 (25.9)
Turns less than 90 degrees
Use a technique similar to other large airplanes: steer the nose wheels far enough beyond the centerline of the turn to keep the main gear close to the centerline.
Turns of 90 degrees or more
Initiate the turn as the intersecting taxiway centerline (or intended exit point) approaches the aft edge of the number 2 window. Initially use approximately full nose wheel steering tiller displacement. Adjust the tiller input as the airplane turns to keep the nose wheels outside of the taxiway centerline, near the outside radius of the turn. Nearing turn completion, when the main gear are clear of the inside radius, gradually release the tiller input as the airplane lines up with the intersecting taxiway centerline or intended taxi path.
Minimum Radius 180 Degree Turns
Coordination with ATC and ground support personnel may be required to complete the operation safely. In some cases (for example: heavy weight, pilot uncertainty of runway and/or taxiway edge margins, nearby construction, vehicles, etc.), towing the airplane to the desired location may be the safest option. If a minimum radius 180° turn is necessary, a ground crew should be used to monitor the wheel path and provide relevant information to the flight crew. The ground crew should be warned of the risk associated with jet blast and position themselves to avoid the hazard. Also ensure that obstacle clearance requirements are met. Since more than idle thrust is required, the flight crew must also be aware of the area directly behind the airplane as well as the area being swept by jet blast during the turn.
Approach the edge of the taxi surface at a shallow angle until the outboard side of the main gear wheels are near the edge. The lower outboard corner of the pilot’s number 1 window is a good visual reference for the outboard side of the main gear wheels on the same side. The lower inboard corner of the pilot’s number 1 window is also a good reference for the opposite side main gear wheels.
Turning radius during 180° turns can be reduced with lower engine thrust and less nose gear tire wear by following a few specific taxi techniques. Taxi the airplane so that the main gear tires are as close as possible to the runway edge.This provides more runway surface to make the turn. Stop the airplane completely with the thrust at idle. Stopping the airplane in a turn is not normally recommended due to higher nose landing gear loads and the increased thrust required to start the airplane moving again. However, since a minimum radius turn is generally beyond the scope of normal taxi operations, it can be treated as a special case. Hold the tiller to the maximum steering angle, release the brakes, then add thrust on the outboard engine. Only use the engine on the outboard side of the turn and maintain 5 knots or less during the turn to minimize turn radius. Light intermittent braking on the inside main gear helps decrease turn radius. As the airplane passes through 90° of turn, gradually reduce the tiller input as required to align the airplane with the new direction of taxi. These actions result in a low speed turn and less runway being used. Wind, slope, runway or taxiway surface conditions, and center of gravity may also affect the turning radius.
Taxi - Adverse Weather
Taxi under adverse weather conditions requires more awareness of surface conditions.
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：757 Flight Crew Training Manual 机组训练手册(22)
