As targets move past the half-way position, adjust antenna tilt angle and range setting as necessary to avoid overscanning. Detection of targets closer than 20 NM may be difficult as the large tilt down settings being used may result in excessive ground clutter and/or more distant storms not being detected.
Cooling Faults
Caution: If COOL or COOL FAULT is displayed, the system should be shut
down at all times not needed for weather avoidance. The system
will not automatically shutdown during an overheat condition,
allowing Flight Crews to keep the radar on as long as possible if
needed for weather avoidance. The system will display COOL
FAULT until it fails due to overheat.
Storm Height
Most formulas and charts used to determine storm heights are complex as a result of the accuracy of calibration and the curvature of the earth. However, the following is a method that estimates the top of the detectable moisture (radar top) and is independent of calibration and curvature problems:
While scanning for storm targets, the most effective tilt angle of the antenna depends upon the altitude of the aircraft and the selected range. Once a storm is detected by varying the tilt angle (see previous table), decrease the tilt until the ground return touches the center of the storm and note the tilt angle displayed on the radar indicator. Now, increase the tilt until the storm disappears and again note the tilt angle. The difference of these two settings is important and eliminates the need of calibration corrections. Multiplying this tilt difference figure times the distance of the storm from the aircraft equals the storm height above ground level (i.e., a five degree difference of a storm at fifty miles equals a storm height of 250 or 25,000 ft. AGL).
Recall, the radar top is only the top of the moisture return and not the top of the cloud. Experience has shown that an additional 10,000 to 15,000 feet must be added to the radar top to ensure total clearance of the storm area.
Overwater Operating Procedures
.
Do not use MAP mode for weather detection.
.
Limit the use of 320 NM range to MAP mode. Weather detection is marginal beyond 220 NM.
.
Use 160 NM range for weather surveillance with tilt down 3 degrees and expect some sea clutter at the outer limits, (i.e., above 120 NM).
.
As weather is detected, range down to 80 NM then 40 NM using tilt to determine the “radar tops.” Radar tops should be avoided by approximately 10,000 to 15,000 feet. Circumnavigate if required.
.
Periodically return to 160 NM to re-examine the “big picture.”
INTENTIONALLY LEFT BLANK ENGINE OPERATION DURING SEVERE PRECIPITATION
Flights should be conducted to avoid moderate to serve thunderstorm activity by overflight or circumnavigation. To the maximum extent possible, moderate to heavy rain/hail should also be avoided. Weather radar, pilot reports, and flight crew observations may be used by the flight crew to determine when moderate to heavy rain/hail/sleet is anticipated. Should flight in moderate to heavy rain/hail/sleet be encountered or anticipated, refer to SEVERE RAIN/ ICE/ TURBULENCE CHECKLIST, Section 3.
INTENTIONALLY LEFT BLANK WINDSHEAR AVOIDANCE AND RECOVERY PROCEDURES
The first and foremost rule is to avoid windshear. As enhanced detection and guidance capabilities become available, the pilot must not perceive these aids as providing the capability to penetrate windshear. These aids are intended to be used for avoidance only, in the same manner as radar is used as an aid in avoiding thunderstorms.
Microburst Windshear Probability Guidelines
Observation Probability Of Windshear
Presence Of Convective Weather Near Intended Flight Path
.
With Localized Strong Winds (tower report or observed blowing dust, rings of dust, tornado-line features, etc.) ............................ HIGH
.
With Heavy Precipitation (observed or radar indications of contour, red or attenuation shadow) ..................................................... HIGH
.
With Rainshower ........................................................................ MEDIUM
.
With Lightning............................................................................ MEDIUM
.
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本文鏈接地址：MD-80 Flight Manual 麥道80飛行手冊 2(42)
