background image

TM106101(8/01)

RDR-1600 Pilot’s Guide

53

Advisory Circulars (Cont.)

52

RDR-1600 Pilot’s Guide

TM106101(8/01)

Advisory Circulars (Cont.)

AC 00-24B

1/20/83

radar echoes depends on echo intensity, spacing between the echoes,
and the capabilities of you and your aircraft. Remember that weather
radar detects only precipitation drops; it does not detect turbulence.
Therefore, the radar scope provides no assurance of avoiding turbulence.
The radar scope also does not provide assurance of avoiding instrument
weather from clouds and fog. Your scope may be clear between intense
echoes; this clear area does not necessarily mean you can fly between
the storms and maintain visual sighting of them.

f. Remember that while hail always gives a radar echo, it may fall

several miles from the nearest visible cloud and hazardous turbulence
may extend to as much as 20 miles from the echo edge. Avoid intense or
extreme level echoes by at least 20 miles; that is, such echoes should be
separated by at least 40 miles before you fly between them. With weaker
echoes you can reduce the distance by which you avoid them.

7. DO'S AND DON'TS OF THUNDERSTORM FLYING.

a. Above all, remember this: never regard any thunderstorm lightly

even when radar observers report the echoes are of light intensity.
Avoiding thunderstorms is the best policy. Following are some do's and
don'ts of thunderstorm avoidance:

(1) Don't land or takeoff in the face of an approaching thunder-

storm. A sudden gust front of low level turbulence could cause loss of
control.

(2) Don't attempt to fly under a thunderstorm even if you can see

through to the other side. Turbulence and wind shear under the storm
could be disastrous.

(3) Don't fly without airborne radar into a cloud mass containing

scattered embedded thunderstorms. Scattered thunderstorms not embed-
ded usually can be visually circumnavigated.

(4) Don't trust the visual appearance to be a reliable indicator of the

turbulence inside a thunderstorm.

(5) Do avoid by at least 20 miles any thunderstorm identified as

severe or giving an intense radar echo. This is especially true under the
anvil of a large cumulonimbus.

(6) Do circumnavigate the entire area if the area has 6/10 thunder-

storm coverage.

(7) Do remember that vivid and frequent lightning indicates the

probability of a severe thunderstorm.

(8) Do regard as extremely hazardous any thunderstorm with tops

35,000 feet or higher whether the top is visually sighted or determined by
radar.

AC 00-24B

1/20/83

during massive water ingestion. Although the exact mechanism of these
water-induced engine stalls has not bee determined, it is felt that thrust
changes may have an adverse effect on engine stall margins in the pres-
ence of massive water ingestion.

(3) Avoidance of severe storm systems is the only measure as-

sured to be effective in preventing exposure to this type of multiple engine
damage/flameout. During an unavoidable encounter with severe storms
with extreme precipitation, the best known recommendation is to follow
the severe turbulence penetration procedure contained in the approved
airplane flight manual with special emphasis on avoiding thrust changes
unless excessive airspeed variations occur.

6. WEATHER RADAR.

a. Weather radar detects droplets of precipitation size. Strength of the

radar return (echo) depends on drop size and number. The greater the
number of drops, the stronger is the echo; and the larger the drops, the
stronger is the echo. Drop size determines echo intensity to a much
greater extent that does drop number. Hailstones usually are covered with
a film of water and, therefore, act as huge water droplets giving the
strongest of all echoes.

b. Numerous methods have been used in an attempt to categorize the

intensity of a thunderstorm. To standardize thunderstorm language
between weather radar operators and pilots, the use of Video Integrator
Processor (VIP) levels is being promoted.

c. The National Weather Service (NWS) radar observer is able to

objectively determine storm intensity levels with VIP equipment. These
radar echo intensity levels are on a scale of one to six. If the maximum
VIP Levels are 1 "weak" and 2 "moderate," then light to moderate tur-
bulence is possible with lightning. VIP Level 3 is "strong" and severe tur-
bulence is possible with lightning. VIP Level 4 is "very strong" and severe
turbulence is likely with lightning. VIP Level 5 is "intense" with severe tur-
bulence, lightning, hail likely, and organized surface wind gusts. VIP Level
6 is "extreme' with severe turbulence, lightning, large hail, extensive sur-
face wind gusts, and turbulence.

d. Thunderstorms build and dissipate rapidly. Therefore, do not

attempt to plan a course between echoes. The best use of ground radar
information is to isolate general areas and coverage of echoes. You must
avoid individual storms from in-flight observations either by visual sighting
or by airborne radar. It is better to avoid the whole thunderstorm area than
to detour around individual storms unless they are scattered.

e. Airborne weather avoidance radar is, as its name implies, for avoid-

ing severe weather - not for penetrating it. Whether to fly into an area of

Summary of Contents for CP-113K

Page 1: ...PREFLIGHT PFT 10 4 1 PREFLIGHT WARNING 10 5 0 THEORY OF OPERATION 11 5 1 GENERAL 11 5 2 RADAR PRINCIPLES 12 5 3 WEATHER RADAR PRINCIPLES 13 5 4 RADAR REFLECTIVITY 14 5 5 WEATHER DISPLAY CALIBRATION 1...

Page 2: ...ST OF ILLUSTRATIONS FIGURE TITLE PAGE 2 1 Typical System Block Diagram 2 2 1 1 Receiver Transmitter 3 2 1 2 DA 1203A Drive Assembly with AA4512A 12 Flat Plate Antenna 3 2 1 3 CP 113K Control Panel 3 2...

Page 3: ...three air to surface search and detection modes and two conventional weather avoid ance modes This lightweight digital X band radar system provides a peak power of 10 kW and is primarily designed for...

Page 4: ...ved by the antenna are amplified and sent to the radar display indicator The flat panel antenna which is available in diameters of 10 12 or 18 inches scans 60 or 120 degrees Swept by a motor driven ge...

Page 5: ...s and a code feature identifies the beacons Beacon Formatting allows for the display of either standard or DO 172 type beacons This information can be displayed in any of eight separate ranges Rainfal...

Page 6: ...e Tilt Control Knob is pressed in the stabilization function is active When this knob is pulled out the stabilization function is turned off TILT Adjusts antenna tilt angle Figure 3 2 1 Tilt Control 3...

Page 7: ...rotary potentiometer that controls the gain of the Search receiver CODE Pressing this switch selects Beacon Codes in a sequential cyclic fashion i e Code 0 Code 1 Code 2 Code 15 or Code 0 Code 1 Code...

Page 8: ...then move the function selector to TEST No display appears in the STBY position and the radar does not transmit in either STBY or TEST The test pattern scans 120 and automatically selects the 80 mile...

Page 9: ...2 RADAR PRINCIPLES Radar is fundamentally a distance measuring system using the principle of radio echoing The term RADAR is an acronym for Radio Detecting And Ranging It is a method for locating targ...

Page 10: ...5 12 0 1 0 5 Light to moderate turbulence is possible with lightning 1 Green 1 4 0 04 0 17 Weak 1 0 25 2 5 01 0 1 Light to moderate turbulence is possible with lightning 0 Black Less than 1 Less than...

Page 11: ...dar beam to effectively look deeper into and through heavy rain to search for possible storm cells beyond While Attenuation Compensation does not eliminate precipitation attenuation it does allow the...

Page 12: ...e displayed range Figure 6 3 1 Weather Alert with Target Alert Display 6 0 WEATHER OPERATIONS 6 1 WEATHER MODE WX The RDR 1600 will provide you with target information to a greater degree than ever po...

Page 13: ...the precipitation reflection correlates with the degree of turbulence found in a thunderstorm The most severe turbulence in the storm however may not be at the same place that gives the greatest rada...

Page 14: ...results can be obtained Note It takes an experienced eye to identify hooks and fingers and other radar echo characteristics which can indicate hail or torna does However the pilot can be sure that an...

Page 15: ...icing would defi nitely exist but in the second case the pure crystals would offer no danger 1 It should be remembered however that super cooled water and ice crystals can co exist In each case the r...

Page 16: ...e still accessible Figure 6 5 10 1 Short Range Display In the weather mode the RDR 1600 is unable to ascertain radar returns from close in On the short range displays the RDR 1600 paints a red arc in...

Page 17: ...ost intense echoes are severe thunderstorms Remember that hail may fall several miles from the cloud and hazardous turbulence may extend as much as 20 miles from the storm Avoid the most intense echoe...

Page 18: ...ntensity will vary with the degree to choppiness Above all remember Never regard any thunderstorm as LIGHT even when radar observers report the echoes are of light intensity Avoiding thunder storms is...

Page 19: ...e detectable range and the area of illumination A large incident angle gives the radar system a smaller detectable range of operation due to a minimized reflection of direct radar energy However the i...

Page 20: ...eyond 10 mile range SR1 and SR2 are the same as SR3 The radar s long range mapping compatibility may be used to recognize known well defined targets such as mountains lakes rivers or cities Use of gai...

Page 21: ...storm s approximate size and relative direction of movement The correct procedure for weather avoidance is to aim the antenna directly at the storm not above it or at the ground The tilt control perm...

Page 22: ...m is being displayed Antenna Tilt Angle Altitude ft 10 12 18 Line of Sight Range SM 5 000 7 0 6 0 5 0 87 10 000 6 0 5 0 4 0 123 15 000 5 5 4 0 3 0 150 20 000 4 5 3 5 2 5 174 25 000 4 0 3 0 2 0 194 30...

Page 23: ...s climbing descending or turning When the aircraft departs from straight and level flight the stabilization system automatically adjusts the antenna position to compensate for the change Both limits a...

Page 24: ...se two frames will be a combination of up to four slashes Varying the combina tions of the inner slashes makes it possible to identify any one of fifteen dif ferent DO 172 beacon codes This feature is...

Page 25: ...rt transmitted pulse and the long range will use a long transmitted pulse This is an incompatible situation in that the transmitter cannot transmit both a long and short pulse at the same time In this...

Page 26: ...s plus 7 5 watts Power Bus maximum lighting power drain from 28 Vdc lighting bus Power Draw using 5 Vac 10 watts maximum electrical and lighting 400 Hz Lighting input power drain from 28 Vdc power bus...

Page 27: ...ws a schematic cross section of a thunderstorm with areas out side the cloud where turbulence may be encountered 2 It is almost impossible to hold a constant altitude in a thunder storm and maneuverin...

Page 28: ...nsity and frequency have no simple relationship to other storm parameters severe storms as a rule have a high frequency of lightning i Engine Water Ingestion 1 Turbine engines have a limit on the amou...

Page 29: ...20 83 during massive water ingestion Although the exact mechanism of these water induced engine stalls has not bee determined it is felt that thrust changes may have an adverse effect on engine stall...

Page 30: ...ou cannot avoid penetrating a thunderstorm following are some do s BEFORE entering the storm 1 Tighten your safety belt put on your shoulder harness if you have one and secure all loose objects 2 Plan...

Page 31: ...fe distance can be determined by using the equations in the Appendix This criterion is now accepted by many indus trial organizations and is based on limiting exposure of humans to an average power de...

Page 32: ...wer density of 1 mw cm2 the distance in meters from the antenna may be calculated by where Rs the minimum safe distance in meters P Transmitted average power in watts G Antenna gain PROCEDURES The abo...

Page 33: ...rne weather radar Antenna Diameter 18 inches 45 6 cm Transmitter Frequency 9375 30 MHz Wave Length 3 2 cm Pulse Length 2 5 microseconds search Pulse Repetition 200 Hz Peak Power 10 kilowatts Average P...

Page 34: ...elope in which the radiation level exceeds the U S Government standard of 1 mW per square centimeter all personnel should remain beyond the distance indicated in the illustration below The distance to...

Reviews: