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airspeeds close.
7.23.3. In an offset formation, the combination of airspeed and angular adjustments complicates the
problem. You should mark the angular offset and desired separation on the scope with either a
mechanical or an electronic cursor. Avoid extreme corrections when flying in formations.
7.23.4. This example presents one basic way to establish a position at a 60o offset at 1 NM (Figure 7.19).
First, maneuver the aircraft so that the lead's radar return is at the desired distance from the heading
marker (in this case 1 NM) and turn to lead's heading. Secondly, adjust airspeed so that lead's return
moves parallel to the heading marker toward the angular offset (this mechanical cursor is offset 60o from
the heading flash). Once in position, adjust airspeed to match leads. Equipment and capabilities vary
among aircraft, so expand upon these basics as necessary.
7.23.5. Aircraft equipped with station-keeping equipment (SKE) should follow the recommendations of
their associated manuals.
7.24. Weather Avoidance. Severe turbulence, hail, and icing associated with thunderstorms constitute
severe hazards to flight. You must avoid these thunderstorms whenever possible. Airborne weather
radar, if operated and interpreted properly, can be an invaluable aid in avoiding thunderstorm areas.
7.24.1. You must be aware of factors and limitations affecting thunderstorm radar returns to get the most
out of the radar. Some of these factors aren't meteorological and depend on the characteristics of the
radar and the way it is used. The same weather target can vary considerably in its appearance from
ground mapping mode to weather mode. Navigators must ensure they use the radar as intended for
weather avoidance. Primary meteorological factors that affect radar returns are the amount of moisture
in the weather target and atmospheric absorption characteristics between the radar antenna and the
target.
194 AFPAM11-216 1 MARCH 2001
Figure 7.19. Station Keeping.
7.24.2. The predominant weather-induced returns on most radarscopes are caused by precipitation-size
water droplets, not by clouds. Intense returns indicate the presence of very large droplets. These large
droplets are generally associated with the most hazardous phenomena; those with strong vertical
currents which are necessary to maintain these droplets in the cloud. It is possible, however, to
encounter such strong turbulence in an echo-free area or even in an adjacent cloud-free area, so avoiding
areas giving intense returns will not necessarily guarantee safe flight in the vicinity of thunderstorms.
Refer to your command guidance for weather avoidance distances. Make careful note of all areas
forecast to have the potential for hazardous weather.
7.24.3. Generally, the map mode of the radar with a moderate amount of gain applied is adequate for
obtaining a return from hazardous cells. Sometimes, ground returns hamper detection in the area by
hiding the storm. This can occur in mountainous areas where ground returns are similar and airmass
lifting action breeds the cells. For these reasons, raising the radar tilt or switching to pencil beam (or
both) are techniques that will aid weather detection.
7.24.4. There are two types of weather avoidance with radar: (1) avoidance of isolated thunderstorms
and (2) penetration of a line of thunderstorms. Avoid an isolated return by first identifying it and then
circumnavigating it at a safe distance.
7.24.5. After detecting a weather system, determine its extent. Analyze the weather's layout relative to
planned track and decide either to deviate around it or penetrate the line. If the system is complex,
remember your deviation could worsen the situation by flying into a sucker hole, where a solid system
could surround the aircraft. Sometimes, what seems to be a good heading at short range will seem
foolish when viewed at long range. Remember that turning around is always an option and ARTCC can
sometimes assist in weather analysis.
7.24.6. A simple technique for flying around weather at a preferred distance (say 20 NM) is the flying
disc technique. Imagine the aircraft is a disc defined by the 20 NM range mark on the PPI. The heading
marker is the nose of the disc. Draw an imaginary tangent from the disc to the edge of the weather (or
AFPAM11-216 1 MARCH 2001 195
use a pencil or plotter). Turn the aircraft the same number of degrees that it would take to get the
heading marker to fire parallel to the tangent. After the turn, recheck the heading in the same manner.
This technique works best with a scan of more than 180o (Figure 7.20).
Figure 7.20. Weather Avoidance.
7.24.7. Penetration of a line of thunderstorms is a last resort and presents a different problem. Since the
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