Weather Radio User Manual

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Summary of content (161 pages)

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Honeywell International Inc. Commercial Electronic Systems 5353 W. Bell Rd. Glendale, Arizona 85308-- 3912 U.S.A. (CAGE 55939) PRIMUSr 880 Digital Weather Radar System Pilot’s Guide Printed in U.S.A. Pub. No.
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PRIMUSr 880 Digital Weather Radar System Table of Contents Section Page 1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 2. SYSTEM CONFIGURATIONS . . . . . . . . . . . . . . . . . 2-1 3. OPERATING CONTROLS . . . . . . . . . . . . . . . . . . . . 3-1 WI- 880 Weather Radar Indicator Operation . . . . . . WC- 880 Weather Radar Controller Operation . . . . WC- 884 Weather Radar Controller Operation . . . . Hidden Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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PRIMUSr 880 Digital Weather Radar System Table of Contents (cont) Section Page 5. RADAR FACTS (cont) Rain Echo Attenuation Compensation Technique (REACT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Shadowing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Turbulence Probability . . . . . . . . . . . . . . . . . . . . . Turbulence Detection Theory . . . . . . . . . . . . . . . Turbulence Detection Operation . . . . . . . . . . . . . Hail Size Probability . . . . . . .
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PRIMUSr 880 Digital Weather Radar System Table of Contents (cont) A FEDERAL AVIATION ADMINISTRATION (FAA) ADVISORY CIRCULARS (CONT) SUBJECT: THUNDERSTORMS . . . . . . . . . . . . . . . Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Related Reading Material . . . . . . . . . . . . . . . . . . . General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hazards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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PRIMUSr 880 Digital Weather Radar System Table of Contents (cont) List of Illustrations (cont) Figure Page 5--1 Positional Relationship of an Airplane and Storm Cells Ahead as Displayed on Indicator . . . . . . . . . 5--2 Antenna Beam Slicing Out Cross Section of Storm During Horizontal Scan . . . . . . . . . . . . . . . . . . . . . . 5--3 Sea Returns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5--4 Radar Beam Illumination High Altitude 12--Inch Radiator . . . . . . . . . . . . . .
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PRIMUSr 880 Digital Weather Radar System Table of Contents (cont) List of Illustrations (cont) Figure Page 5--32 Turbulent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5--33 Weather Display With Turbulence . . . . . . . . . . . . . . 5--34 Turbulence Levels (From Airman’s Information Manual) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5--35 Hail Size Probability . . . . . . . . . . . . . . . . . . . . . . . . . .
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PRIMUSr 880 Digital Weather Radar System Table of Contents (cont) List of Tables Table Page 2--1 Dual Control Mode Truth Table . . . . . . . . . . . . . . . . 2--2 PRIMUSR 880 Weather Radar Equipment List . . . . 3--1 3--2 3--3 3--4 3--5 3--6 Rainfall Rate Color Coding . . . . . . . . . . . . . . . . . . . Target Alert Characteristics . . . . . . . . . . . . . . . . . . . Rainfall Rate Color Coding . . . . . . . . . . . . . . . . . . . WC--880 Controller Target Alert Characteristics . . .
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PRIMUSr 880 Digital Weather Radar System 1. Introduction The PRIMUSR 880 Digital Weather Radar System is a lightweight, X- band digital radar with alphanumerics designed for weather detection (WX) and ground mapping (GMAP). The primary purpose of the system is to detect storms along the flightpath and give the pilot a visual indication in color of their rainfall intensity and turbulence content. After proper evaluation, the pilot can chart a course to avoid these storm areas.
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PRIMUSr 880 Digital Weather Radar System The radar indicator is equipped with the universal digital interface (UDI). This feature expands the use of the radar indicator to display information such as checklists, short and long range navigation displays (when used with a Honeywell DATA NAV system) and electrical discharge data from Honeywell’s LSZ- 850 Lightning Sensor System (LSS). NOTE: Introduction 1-2 Refer to Honeywell Pub.
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PRIMUSr 880 Digital Weather Radar System 2. System Configurations The PRIMUSâ 880 Digital Weather Radar System can be operated in many configurations to display weather or ground mapping information on a radar indicator, electronic flight instrument system (EFIS) display, multifunction display (MFD), or on a combination of these displays. The various system configurations are summarized in the following paragraphs and shown in figure 2- 1. NOTE: Other configurations are possible but not illustrated.
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PRIMUSr 880 Digital Weather Radar System RTA WU- 880 STAND- ALONE CONFIGURATION INDICATOR WI- 880 SINGLE OR DUAL EFIS OPTION EFIS ONLY CONFIGURATION RTA WU- 880 CONTROLLER WC- 880 STAB TRB PULL VAR MIN GAIN MAX WX SBY OFF RCT GMAP FP TST RADAR MIN GAIN MAX WX SBY OFF PULL ACT SLV STAB TRB PULL VAR RCT GMAP FP TST RADAR TGT TILT - TGT PULL ACT SLV SECT + TILT SECT + - OPTIONAL 2ND CONTROLLER SINGLE OR DUAL EFIS EFIS / MFD CONFIGURATION RTA WU- 880 CONTROLLER WC- 880 STAB TRB
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PRIMUSr 880 Digital Weather Radar System The third system configuration is similar to the second except that a Honeywell multifunction display (MFD) system is added. As before, single or dual controllers can be used. When a single controller is used, all displays show the same radar data. Dual controllers are used to operate in the dual mode. The MFD can be slaved to either controller to duplicate the data displayed on the selected side. Table 2- 1 is a truth table for dual control modes.
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PRIMUSr 880 Digital Weather Radar System 1. ON is used to indicate any selected radar mode. NOTES: 2. “SLV” means that displayed data is controlled by opposite side controller. 3. XXX/2 means that display is controlled by appropriate on--side control for the antenna sweep direction associated with that control. (/2 implies two controllers are on.) 4. In standby, the RTA is centered in azimuth with 15_ upward tilt. Video data is suppressed. The transmitter is inhibited. 5.
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PRIMUSr 880 Digital Weather Radar System WU- 880 RTA WC- 884 CONTROLLER WI- 880 INDICATOR WC- 880 CONTROLLER AD- 46691@ Typical PRIMUSâ 880 Weather Radar Components Figure 2- 2 A28- 1146- 102- 00 System Configurations 2-5/(2-6 blank)
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PRIMUSr 880 Digital Weather Radar System 3. Operating Controls WI- 880 WEATHER RADAR INDICATOR OPERATION All controls used to operate the system display shown in figure 3- 1, are located on the WI- 880 Weather Radar Indicator front panel. There are three basic controllers that are described in this section, they are (in order of description): D WI- 880 Weather Radar Indicator D WC- 880 Weather Radar Controller D WC- 884 Weather Radar Controller. AUTO TILT +1.
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PRIMUSr 880 Digital Weather Radar System 6 5 4 3 7 TRB RANGE STB RCT AZ TGT SCT 8 9 1 2 WX SBY OFF GMAP FP TST PULL VAR MIN 12 GAIN MAX BRT TILT + PULL ACT 10 - 11 SBY LX CLR OFF TST 10 BRT AD- 46693- R1@ WI- 880 Weather Radar Indicator Front Panel View Figure 3- 2 1 Display Area See figure 3- 3 and the associated text which explains the alphanumeric display.
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PRIMUSr 880 Digital Weather Radar System TARGET/TARGET ALERT: T ARM (GREEN) TGT ALERT (YELLOW INVERTED VIDEO) TILT ANGLE FAIL NOTE STB A ALTITUDE COMPENSATED TILT (ACT) ANNUNCIATION REACT: RCT MODE: STBY FSBY WAIT TEST WX WX/T FLTPLN GMAP RANGE RING MARKERS (120- DEGREE SCAN SHOWN) COLOR BAR: 1 2 3 4 T WX CALIBRATED GAIN WX VARIABLE GAIN VAR ! 1 2 3 GMAP CALIBRATED GAIN V A R GMAP VARIABLE GAIN NOTE:MESSAGES ARE LISTED 1 2 3 4 T WX/T CALIBRATED GAIN WX/T VAR VAR ! IN PRIORITY ORDER.
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PRIMUSr 880 Digital Weather Radar System If WX is selected before the initial RTA warmup period is over (approximately 90 seconds), the white WAIT legend is displayed in the mode field. In wait mode, the transmitter and antenna scan are inhibited and the display memory is erased. When the warmup is complete, the system automatically switches to the WX mode. The system, in preset gain, is calibrated as listed in table 4- 1. Rainfall Rate Color in/hr mm/hr .04- .16 1- 4 Green .16- .
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PRIMUSr 880 Digital Weather Radar System D FP (Flight Plan) -- The FP position puts the radar system in the flight plan mode, which clears the screen of radar data so ancillary data can be displayed. Examples of this data are: — Navigation displays — Electrical discharge (lightning) data. NOTE: In the FP mode, the radar RTA is put in standby, the alphanumerics are changed to cyan, and the FLTPLN legend is shown in the mode field. The target (TGT) alert mode can be used in the FP mode.
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PRIMUSr 880 Digital Weather Radar System WARNING FORCED STANDBY MODE MUST BE VERIFIED BY THE OPERATOR TO ENSURE SAFETY FOR GROUND PERSONNEL. 3 TGT (Target) The TGT button is an alternate- action switch that enables and disables the radar target alert feature. Target alert is selectable in all but the 300- mile range. When selected, target alert monitors beyond the selected range and 7.5° on each side of the aircraft heading.
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PRIMUSr 880 Digital Weather Radar System Selected Range (NM) Minimum Target Depth (NM) Target Range (NM) 5 5 5- 55 10 5 10- 60 25 5 25- 75 50 5 50- 100 100 5 100- 150 200 5 200- 250 300 N/A N/A FP (Flight Plan) 5 5- 55 Target Alert Characteristics Table 3- 2 4 RCT (Rain Echo Attenuation Compensation Technique (REACT)) The RCT switch is an alternate- action switch that enables and disables REACT.
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PRIMUSr 880 Digital Weather Radar System The radar antenna is normally attitude stabilized. It automatically compensates for roll and pitch maneuvers (refer to Section 5, Radar Facts, for a description of stabilization). The STB OFF annunciator is displayed on the screen. 6 TRB (Turbulence) The TRB switch is used to select the turbulence detection mode of operation. The TRB mode can only be selected if the FUNCTION switch is in the WX position and the selected range is 50 miles or less.
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PRIMUSr 880 Digital Weather Radar System 10 BRT (Brightness) or BRT/LSS (Lightning Sensor System) The BRT knob is a single- turn control that adjusts the brightness of the display. Clockwise (cw) rotation increases display brightness and counterclockwise (ccw) rotation decreases brightness. An optional BRT/LSS four- position rotary switch selects the separate LSZ- 850 Lightning Sensor System (LSS) operating modes and the brightness control on some models.
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PRIMUSr 880 Digital Weather Radar System 12 GAIN The GAIN knob is a single- turn rotary control and push/pull switch that is used to control the receiver gain. Push in on the GAIN switch to enter the system into the preset calibrated gain mode. Calibrated gain is the normal mode and is used for weather avoidance. In calibrated gain, the rotary portion of the GAIN control does nothing. In calibrated gain, the color bar legend is labeled 1,2,3,4 in WX mode or 1,2,3 in GMAP mode.
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PRIMUSr 880 Digital Weather Radar System WC- 880 WEATHER RADAR CONTROLLER OPERATION The controls and display features of the WC- 880 Weather Radar Controller are indexed and identified in figure 3- 4. Brightness levels for all legend and controls on the indicator are controlled by the dimming bus for the aircraft panel.
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PRIMUSr 880 Digital Weather Radar System 6 5 TRB PULL VAR MIN GAIN MAX 8 1 WX SBY OFF 4 STAB TGT RCT GMAP FP TST RADAR 3 SBY OFF SLV SECT + LX CLR TST LSS PULL ACT TILT - 10 2 AD- 46697- R1@ WC- 880 Weather Radar Controller Configurations Figure 3- 4 NOTES: 1. With a controller without built- in range control, range is controlled from the installed EFIS navigation display 2. Controllers are available with and without the LSS function. 3.
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PRIMUSr 880 Digital Weather Radar System 1 RADAR This rotary switch is used to select one of the following functions. D OFF - This position turns the radar system off. D SBY (Standby) - This position places the radar system in standby; a ready state, with the antenna scan stopped, the transmitter inhibited, and the display memory erased. STBY is displayed on the EFIS/MFD. D WX (Weather) - This position selects the weather detection mode.
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PRIMUSr 880 Digital Weather Radar System NOTES: 1. REACT’s three functions (attenuation compensation, cyan field, and forcing targets to magenta) are switched on and off with the RCT switch. 2. D Refer to Section 5, Radar Facts, for a description of REACT. GMAP (Ground Mapping) - The GMAP position puts the radar system in the Ground Mapping mode. The system is fully operational and all parameters are set to enhance returns from ground targets. NOTE: REACT, TGT, or TRB modes are not selectable in GMAP.
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PRIMUSr 880 Digital Weather Radar System The target alert mode can be used in the FP mode. With target alert on and the FP mode selected, the target alert armed annunciation (green TGT) is displayed. The RTA searches for a hazardous target from 5 to 55 miles and ±7.5 degrees of dead ahead. No radar targets are displayed. If a hazardous target is detected, the target alert armed annunciation switches to the alert annunciation (amber TGT).
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PRIMUSr 880 Digital Weather Radar System 2 TILT The TILT switch is a rotary control that is used to select the tilt angle of antenna beam with relation to the horizon. CW rotation tilts beam upward 0_ to 15_; ccw rotation tilts beam downward 0_ to - 15_. The range between +5_ and - 5_ is expanded for ease of setting. A digital readout of the antenna tilt angle is displayed on the EFIS.
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PRIMUSr 880 Digital Weather Radar System Selecting target alert forces the system to preset gain. Target alert can only be selected in the WX and FP modes.
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PRIMUSr 880 Digital Weather Radar System WARNINGS 1. TURBULENCE CAN ONLY BE DETECTED WITHIN AREAS OF RAINFALL. THE PRIMUSR 880 DIGITAL WEATHER RADAR SYSTEM CANNOT DETECT CLEAR AIR TURBULENCE. 2. UNDETECTED TURBULENCE CAN EXIST WITHIN ANY STORM CELL. REFER TO SECTION 5, RADAR FACTS, OF THIS GUIDE FOR ADDITIONAL INFORMATION. Selecting the 100, 200, or 300 mile range turns off the turbulence detection. The /T is deleted from the mode annunciation and variable gain is engaged if previously selected.
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PRIMUSr 880 Digital Weather Radar System WARNING LOW VARIABLE GAIN SETTINGS CAN ELIMINATE HAZARDOUS TARGETS FROM THE DISPLAY. In GMAP mode, variable gain is used to reduce the level of strong returns from ground targets. Minimum gain is attained with the control at its full ccw position. Gain increases as the control is rotated in a cw direction from full ccw at full cw position, the gain is at maximum. The VAR! legend annunciates variable gain. Selecting RCT or TGT forces the system into calibrated gain.
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PRIMUSr 880 Digital Weather Radar System WC- 884 WEATHER RADAR CONTROLLER OPERATION The controls and display features of the WC- 884 Weather Radar Controller are indexed and identified in figure 3- 5. Brightness levels for all legend and controls on the indicator are controlled by the dimming bus for the aircraft panel. Whenever single or dual radar controllers are used, the radar data is displayed on the EFIS, MFD, or NAV display.
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PRIMUSr 880 Digital Weather Radar System Selecting target alert forces the system into preset gain. Target alert can be selected in the WX and FP modes.
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PRIMUSr 880 Digital Weather Radar System 5 TRB (Turbulence Detection) TRB switch is used to select the turbulence detection mode of operation. The TRB mode can only be selected if the MODE switch is in the WX position and the selected range is 50 miles or less. The weather/turbulence mode is annunciated in the mode field with the green WX/T legend. Areas of at least moderate turbulence are shown in soft white. CAUTION TURBULENCE CAN ONLY BE DETECTED WITHIN AREAS OF RAINFALL.
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PRIMUSr 880 Digital Weather Radar System WARNINGS 1. TO AVOID FLYING UNDER OR OVER STORMS, FREQUENTLY SELECT MANUAL TILT TO SCAN BOTH ABOVE AND BELOW YOUR FLIGHT LEVEL. 2. ALWAYS USE MANUAL TILT FOR WEATHER ANALYSIS. 7 RANGE RANGE is a rotary control used to select one of six ranges (10, 25, 50, 100, 200, and 300 NM). The seventh position of the range switch is flight plan mode.
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PRIMUSr 880 Digital Weather Radar System When the warmup is complete, the system changes the mode field from WAIT to STBY. D TEST- This position selects the radar test mode. A test pattern is displayed to verify that system operates. The green TEST legend is displayed in the mode field. Refer to Section 4, Normal Operation, for a description of the test pattern. WARNING UNLESS THE SYSTEM IS IN FORCED STANDBY, THE TRANSMITTER IS ON AND RADIATING X- BAND MICROWAVE ENERGY IN TEST MODE.
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PRIMUSr 880 Digital Weather Radar System When GMAP is selected, a green GMAP legend is displayed and the color scheme is changed to cyan, yellow, magenta. Cyan represents the least reflective return, yellow is a moderate return, and magenta is a strong return. If GMAP is selected before the initial RTA warmup period is complete, a flashing WAIT legend is displayed. In WAIT mode, the transmitter and antenna scan are inhibited and the memory is erased.
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PRIMUSr 880 Digital Weather Radar System WARNING WHEN LOW SETTINGS OF VARIABLE GAIN ARE USED, HAZARDOUS TARGETS CAN BE ELIMINATED FROM THE DISPLAY. In the GMAP mode, variable gain is used to reduce the level of the typically very strong returns from ground targets. Minimum gain is with the control at its full ccw position. Gain increases as the control is rotated in a cw direction from full ccw. At the full cw position, the gain is at maximum. The VAR legend annunciates variable gain.
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PRIMUSr 880 Digital Weather Radar System Roll Offset D Function - Roll offset permits exact compensation of the antenna roll to eliminate the effects of small errors in the aircraft radar installation. Constantly lopsided ground returns can be eliminated. (Refer to Section 5, Radar Facts, table 5- 5.) D Entry Method - Using only one controller that is in the WX and variable gain modes, select RCT OFF. Push STB 4 times within 3 seconds. Verify that VAR and RCT are not displayed.
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PRIMUSr 880 Digital Weather Radar System Entry Method - Selected by sequencing through the roll offset, pitch offset, and roll gain menus with the STAB button. (Refer to Section 5, Radar Facts, table 5- 10.) D D D Control - Pull the GAIN knob out and use it. Exit Method - Push the GAIN knob in. Push STAB to exit and save settings. NOTES: 1. If installation is configured only for roll offset adjustment, pushing the STB button saves and exits after the roll offset adjustment is made. 2.
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PRIMUSr 880 Digital Weather Radar System 4. Normal Operation PRELIMINARY CONTROL SETTINGS Table 4--1 gives the proper power--up procedure for the PRIMUSR 880 Digital Weather Radar System.
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PRIMUSr 880 Digital Weather Radar System Step Procedure 5 When power is first applied the radar is in WAIT for approximately 90 seconds to allow the magnetron to warm up. Power sequences ON- OFF- ON lasting less than 3 seconds result in a 6- second wait period. NOTE: If forced standby is incorporated, it is necessary to exit forced standby. WARNING OUTPUT POWER IS RADIATED IN TEST MODE. 6 After the warm- up, select the Test mode and verify that the test pattern is displayed as shown in figure 4- 1.
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PRIMUSr 880 Digital Weather Radar System TGT OR VAR ANNUNCIATOR TGT:: P880 WX MODE ANNUNCIATIONS WX RANGE RINGS (WHITE) DTRK 315 VAR:: MAG1 321 TARGET ALERT -- GREEN--SELECTED -- AMBER TGT DETECTED VARIABLE GAIN (AMBER) TGT FMS1 130 NM TEST +11 TEXT AREA ANTENNA TILT ANGLE V VOR1 VOR2 HDG 319 GRAY MAGENTA 50 BLUE 25 15 GSPD 260 KTS YELLOW RED WX RANGE ANNUNCIATOR (WHITE) NOTES: GREEN 1. IF THE BITE DETECTS A FAULT IN TEST MODE, FAIL ”N” WILL BE SHOWN. ”N” IS A FAULT CODE 2.
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PRIMUSr 880 Digital Weather Radar System WI--880 Indicator Test Pattern With TEXT FAULT Enabled Figure 4--3 Standby When Standby is selected, and the radar is not in dual control mode (refer to table 2--1, dual control mode truth table, for dual control operation), the antenna is stowed in a tilt--up position and is neither scanning nor transmitting. Standby should be selected when the pilot wants to keep power applied to the radar without transmitting.
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PRIMUSr 880 Digital Weather Radar System To aid in target interpretation, targets are displayed in various colors. Each color represents a specific target intensity. The intensity levels chosen are related to the National Weather Service (NWS) video integrated processor (VIP) levels. In the WX mode, the system displays five levels as black, green, yellow, red, and magenta in increasing order of intensity.
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PRIMUSr 880 Digital Weather Radar System Radar Mode - Ground Mapping NOTE: Refer to Tilt Management in Section 5, Radar Facts, for additional information on the use of tilt control. Ground- mapping operation is selected by setting the controls to GMAP. The TILT control is turned down until a usable amount of navigable terrain is displayed. The degree of down- tilt depends on the aircraft altitude and the selected range.
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PRIMUSr 880 Digital Weather Radar System D EFIS/MFD/ND - Faults are normally shown when test is selected. NOTES: 1. Some weather failures on EFIS are annunciated with an amber WX. 2. Some EFIS installations can power up with an amber WX if weather radar is turned off. 3. If the fault code option is selected, they are shown with the FAIL annunciation (e.g., FAIL 13).
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PRIMUSr 880 Digital Weather Radar System 5. Radar Facts RADAR OPERATION The PRIMUSâ 880 Digital Weather Radar works on an echo principle. The radar sends out short bursts of electromagnetic energy that travel through space as a radio wave. When the traveling wave of energy strikes a target, some of the energy reflects back to the radar receiver. Electronic circuits measure the elapsed time between the transmission and the reception of the echo to determine the distance to the target (range).
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PRIMUSr 880 Digital Weather Radar System AIRCRAFT HEADING 0 100 80 60 40 WX +0.6 20 AD- 12055- R2@ Positional Relationship of an Airplane and Storm Cells Ahead as Displayed on Indicator Figure 5- 1 The drawing is laid out to simulate the face of the indicator with the semicircular range marks. To derive a clearer concept of the picture that the indicator presents, imagine that the storm is a loaf of sliced bread standing on end.
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PRIMUSr 880 Digital Weather Radar System at it from above, as shown in figure 5- 2. The height of the slice selected for display depends upon the altitude and also upon the upward or downward TILT adjustment made to the antenna. Antenna Beam Slicing Out Cross Section of Storm During Horizontal Scan Figure 5- 2 Weather radar can occasionally detect other aircraft, but it is not designed for this purpose and should never be considered a collision- avoidance device.
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PRIMUSr 880 Digital Weather Radar System When the antenna is tilted downward for ground mapping, two phenomena may occur that can confuse the pilot. The first is called ”The Great Plains Quadrant Effect”that is seen most often when flying over the great plains of central United States. In this region, property lines (fences), roads, houses, barns, and power lines tend to be laid out in a stringent north- south/east- west orientation.
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PRIMUSr 880 Digital Weather Radar System TILT MANAGEMENT The pilot can use tilt management techniques to minimize ground clutter when viewing weather targets. Assume the aircraft is flying over relatively smooth terrain which is equivalent to sea level in altitude. The pilot must make adjustments for the effects of mountainous terrain. ELEVATION IN FEET The figures below help to visualize the relationship between tilt angle, flight altitude, and selected range.
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PRIMUSr 880 Digital Weather Radar System ELEVATION IN FEET 40,000 ANTENNA ADJUSTED FOR 2.8 UPTILT 30,000 20,900 FT 20,000 10,500 FT 7.9 4,200 FT 10,000 0 10 20,900 FT 10,500 FT 1.15 4,200 FT 5,000 20 30 40 50 RANGE NAUTICAL MILES 60 70 80 AD- 17718- R1@ Radar Beam Illumination Low Altitude 12- Inch Radiator Figure 5- 6 ELEVATION IN FEET 40,000 ANTENNA ADJUSTED FOR 2.8 UPTILT 30,000 14,000 FT 20,000 3,000 FT 10,000 14,000 FT 7,400 FT 5,000 0 7,400 FT 5.
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PRIMUSr 880 Digital Weather Radar System Tables 5- 1 and 5- 2 give the approximate tilt settings at which ground targets begin to be displayed on the image periphery for 12- and 18- inch radiators. The range at which ground targets can be observed is affected by the curvature of the earth, the distance from the aircraft to the horizon, and altitude above the ground. As the tilt control is rotated downward, ground targets first appear on the display at less than maximum range.
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PRIMUSr 880 Digital Weather Radar System RANGE SCALE (NM) 5 10 25 50 100 200 - 12 -4 -1 +1 - 10 -3 0 +1 -8 -2 0 +1 -6 -1 +1 -4 0 +1 300 LINE OF SIGHT (NM) 35,000 30,000 25,000 20,000 15,000 - 11 -2 +1 +2 10,000 -6 -0 +2 +2 -1 +2 +2 5,000 -5 4,000 -4 0 +2 +3 3,000 -2 +1 +3 +3 2,000 0 +2 +3 +3 1,000 +2 +3 +3 246 (LINE OF SIGHT LIMITED REGION) 40,000 (TILT LIMITED REGION) ALTITUDE (FEET) 230 213 195 174 151 123 87 78 67 55 39 AD- 29830- R2@ Appr
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PRIMUSr 880 Digital Weather Radar System RANGE SCALE (NM) 10 25 50 100 - 12 -8 - 11 -8 - 10 -7 - 13 -9 -7 - 11 -8 -6 - 10 -7 -6 -5 200 ALTITUDE (FEET) 30,000 25,000 20,000 15,000 10,000 - 13 -8 -6 5,000 -9 -6 -5 4,000 -8 -6 -5 3,000 -7 -5 -5 2,000 -6 -5 -4 1,000 -5 -4 246 (LINE OF SIGHT LIMITED REGION) 35,000 (TILT LIMITED REGION) 40,000 LINE OF SIGHT (NM) 230 213 195 174 151 123 87 78 67 55 39 AD- 35710@ Approximate Tilt Setting for Minimal Ground Target
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PRIMUSr 880 Digital Weather Radar System Range Scale (NM) Altitude (Feet) 100 200 40,000 -6 -3 -2 246 35,000 -5 -2 230 213 0.5 1.0 2.
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PRIMUSr 880 Digital Weather Radar System Tilt management is often misunderstood. It is crucial to safe operation of airborne weather radar. If radar tilt angles are not properly managed, weather targets can be missed or underestimated. The upper levels of convective storms are the most dangerous because of the probability of violent windshears and large hail. But hail and winshear are not very reflective because they lack reflective liquid water.
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PRIMUSr 880 Digital Weather Radar System D Convective thunderstorms become much less reflective above the freezing level. This reflectivity decreases gradually over the first 5000 to 10,000 feet above the freezing level, as shown in figure 5- 10. FREEZING LEVEL AD- 35696@ Convective Thunderstorms Figure 5- 10 The aircraft in figure 5- 10 has a clear radar indication of the thunderstorm, probably with a shadow in the ground returns behind it.
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PRIMUSr 880 Digital Weather Radar System D Proper tilt management demands that tilt be changed continually when approaching hazardous weather so that ground targets are not painted by the radar beam, as shown in figure 5- 12. FREEZING LEVEL AD- 35698@ Proper Tilt Technique Figure 5- 12 D After heading changes in a foul weather situation, the pilot should adjust the tilt to see what was brought into the aircraft’s flightpath by the heading changes, as shown in figure 5- 13.
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PRIMUSr 880 Digital Weather Radar System D Under the right conditions, a dangerous thunder bumper can develop in 10 minutes, and can in fact spawn and mature under the radar beam as the aircraft approaches it, as shown in figure 5- 14. If flying at 400 kt groundspeed, a fast developing thunderstorm that spawns 67 NM in front of the aircraft can be large enough to damage the aircraft by the time it arrives at the storm.
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PRIMUSr 880 Digital Weather Radar System D The antenna size used on the aircraft alters the best tilt settings by about 1_. However, tilt management is the same for either size, as shown in figure 5- 16. 10- IN. ANTENNA HAS 10 BEAM 12- IN. ANTENNA HAS 7.9 BEAM 18- IN. ANTENNA HAS 5.6 BEAM 24- IN. ANTENNA HAS 4.2 BEAM Antenna Size and Impact on Tilt Management Figure 5- 16 NOTE: D A 10- inch antenna is shown for illustration purposes only.
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PRIMUSr 880 Digital Weather Radar System ALTITUDE COMPENSATED TILT (ACT) The PRIMUSâ 880 Digital Weather Radar has an ACT feature that can be selected by pulling out the tilt control knob. This feature is annunciated on the radar display by adding an A suffix to the tilt readout. While in ACT or manual tilt the digital tilt readout always shows the actual (true) tilt of the antenna. In ACT, the antenna tilt is automatically adjusted with regard to the selected range and the aircraft’s barometric attitude.
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PRIMUSr 880 Digital Weather Radar System 25 50 100 NM AD- 35703@ Manual Tilt at Low Altitudes Figure 5- 18 A28- 1146- 102- 00 Radar Facts 5-17
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PRIMUSr 880 Digital Weather Radar System STABILIZATION The purpose of the stabilization system is to hold the elevation of the antenna beam relative to the earth’s surface constant at all azimuths, regardless of aircraft bank and pitch maneuvers. The stabilization system uses the aircraft attitude source as a reference. Several sources of error exist in any stabilization system. Dynamic Error Dynamic error is the basis of the stabilization system. Stabilization is a corrective process.
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PRIMUSr 880 Digital Weather Radar System Some vertical gyroscopes have provisions for deactivating the roll- erection torque motor (whenever the airplane banks more than approximately 6_) to reduce the effect of lateral acceleration during turns. To some extent, stabilization error is displayed in the radar image after any speed change and/or turn condition.
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PRIMUSr 880 Digital Weather Radar System Trim Adjustment Flight Condition Effect On Ground Return Display (Over Level Terrain) Roll offset Straight and level Nonsymmetrical display Pitch offset Straight and level Ground displays do not follow contour of range arcs. Roll gain Constant roll angle >20° Nonsymmetrical display Pitch gain Constant pitch angle >5° Ground displays do not follow contour of range arcs.
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PRIMUSr 880 Digital Weather Radar System Stabilization Precheck Prior to performing any of the adjustment procedures, conduct the precheck procedures listed in tables 5- 5 and 5- 6. LEVEL FLIGHT STABILIZATION CHECK Check stabilization in level flight using the procedure in table 5- 5. Step Procedure 1 Trim the aircraft for straight and level flight in smooth, clear air over level terrain. 2 Select the 50- mile range. 3 Rotate the tilt control upward until all ground returns disappear.
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PRIMUSr 880 Digital Weather Radar System 20 15 GMAP 10 5 AD- 17720- R1@ Symmetrical Ground Returns Figure 5- 19 20 15 GMAP 10 5 AD- 17721- R1@ Ground Return Indicating Misalignment (Upper Right) Figure 5- 20 Radar Facts 5-22 A28- 1146- 102- 00
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PRIMUSr 880 Digital Weather Radar System 20 15 10 GMAP 5 AD- 17722- R1@ Ground Return Indicating Misalignment (Upper Left) Figure 5- 21 ROLL STABILIZATION CHECK Once proper operation is established in level flight, verify stabilization in a turn using the procedure in table 5- 6. Procedure Step 1 Place the aircraft in 20°roll to the right. 2 Note the radar display. It should contain appreciably no more returns than found during level flight.
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PRIMUSr 880 Digital Weather Radar System In prolonged turns, gyro precession can occur that is tracked by the stabilization system and appears as undesirable ground targets on the indicator. For example, a 1°precession error (which would probably not be noticed on the gyro horizon) moves the antenna beam approximately 10,500 feet at a point 100 NM from the aircraft, If ground targets between 50 and 80 NM depending on aircraft altitude and the actual setting of the tilt control.
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PRIMUSr 880 Digital Weather Radar System ROLL STABILIZATION CHECK You can make an in- flight adjustment when level flight stabilization errors are detected. This procedure is done by either the WC- 880 or WC- 884 Weather Radar Controller or the WI- 880 Weather Radar Indicator. During this procedure, described in table 5- 7, the GAIN control acts as roll offset control. After the procedure the GAIN control reverts to acting as a gain control.
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PRIMUSr 880 Digital Weather Radar System Step 10 NOTE: Procedure Push the STAB (STB) button to go to the next menu (pitch offset). Once set, the roll compensation is stored in nonvolatile memory in the RTA. It is remembered when the system is powered down.
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PRIMUSr 880 Digital Weather Radar System WX Roll Offset Adjustment Display - Final Figure 5- 24 A28- 1146- 102- 00 Radar Facts 5-27
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PRIMUSr 880 Digital Weather Radar System PITCH OFFSET ADJUSTMENT This in- flight adjustment in made in straight and level flight when the ground returns do not follow the contours of the radar display range arcs. The procedure is listed in table 5- 8. Step Procedure 1 If two controllers are installed, one must be turned off. If an indicator is used, the procedure is the same as given below. 2 Fly to an altitude of 10,000 feet AGL or greater. 3 Set range to 25 NM.
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PRIMUSr 880 Digital Weather Radar System ROLL GAIN ADJUSTMENT This in- flight adjustment is made in a bank when the ground returns do not remain symmetrical during turns. The procedure is listed in table 5- 9. Step Procedure 1 If two controllers are installed, one must be turned off. If an indicator is used as the controller, the procedure is the same as given below. 2 Fly to an altitude of 10,000 feet AGL or greater. 3 Set range to 25 NM.
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PRIMUSr 880 Digital Weather Radar System PITCH GAIN ADJUSTMENT This in- flight adjustment is made in a bank when the ground returns do not follow the contours of the range arcs during turns. The procedure is listed in table 5- 10. Step Procedure 1 If two controllers are installed, one must be turned off. If an indicator is used as the controller, the procedure is the same as given below. 2 Fly to an altitude of 10,000 feet AGL or greater. 3 Set range to 25 NM.
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PRIMUSr 880 Digital Weather Radar System INTERPRETING WEATHER RADAR IMAGES From a weather standpoint, hail and turbulence are the principal obstacles to a safe and comfortable flight. Neither of these conditions is directly visible on radar. The radar shows only the rainfall patterns with which these conditions are associated. The weather radar can see water best in its liquid form, as shown in figure 5- 25 (not water vapor; not ice crystals; not hail when small and perfectly dry).
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PRIMUSr 880 Digital Weather Radar System The following are some truths about weather and flying, as shown in figure 5- 26. D Turbulence results when two air masses at different temperatures and/or pressures meet. D This meeting can form a thunderstorm. D The thunderstorm produces rain. D The radar displays rain (thus revealing the turbulence). D In the thunderstorm’s cumulus stage, echoes appear on the display and grow progressively larger and sharper.
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RAINFALL RATE PRIMUSr 880 Digital Weather Radar System 0 RED LEVEL* 20 40 60 NAUTICAL MILES 80 AD- 12057- R2@ Radar and Visual Cloud Mass Figure 5- 26 As masses of warm, moist air are hurled upward to meet the colder air above, the moisture condenses and builds into raindrops heavy enough to fall downward through the updraft. When this precipitation is heavy enough, it can reverse the updraft. Between these downdrafts (shafts of rain), updrafts continue at tremendous velocities.
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PRIMUSr 880 Digital Weather Radar System To find a safe and comfortable route through the precipitation area, study the radar image of the squall line while closing in on the thunderstorm area. In the example shown in figure 5- 27, radar observation shows that the rainfall is steadily diminishing on the left while it is very heavy in two mature cells (and increasing rapidly in a third cell) to the right. The safest and most comfortable course lies to the left where the storm is decaying into a light rain.
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PRIMUSr 880 Digital Weather Radar System WEATHER DISPLAY CALIBRATION Ground based radar observers of the National Weather Service (NWS) currently use video integrator processor (VIP) levels in reporting thunderstorm intensity levels. These radar echo intensity levels are on a scale of one to six. Refer to Section 6 of FAA Advisory Circular AC- 00- 24B for additional details.
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PRIMUSr 880 Digital Weather Radar System REFLECTIVITY DISPLAY LEVEL RAINFALL RATE MM/HR 4 (MAGENTA) GREATER THAN 50 VERY STRONG 3 (RED) 12 - 50 4 25 - 50 (1 - 2) STRONG 3 12 - 25 (0.5 - 1) MODERATE 2 2.5 - 12 (0.1 - 0.5) WEAK 1 0.25 - 2.5 (0.01 - 0.1) 0.5 - 2 2 (YELLOW) 4 - 12 0.17 - 0.5 1 (GREEN) 1- 4 0.04 - 0.
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PRIMUSr 880 Digital Weather Radar System VARIABLE GAIN CONTROL The PRIMUSâ 880 Digital Weather Radar variable gain control is a single turn rotary control and a push/pull switch that is used to control the radar’s receiver gain. With the switch pushed in, the system is in the preset, calibrated gain mode. In calibrated gain, the rotary control does nothing. When the GAIN switch is pulled out, the system enters the variable gain mode. Variable gain is useful for additional weather analysis.
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PRIMUSr 880 Digital Weather Radar System Honeywell has incorporated attenuation compensation that adjusts the receiver gain by an amount equal to the amount of attenuation. That is, the greater the amount of attenuation, the higher the receiver gain and thus, the more sensitive the receiver. Attenuation compensation continuously calibrates the display of weather targets, regardless of the amount of attenuation.
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PRIMUSr 880 Digital Weather Radar System With REACT Selected REACT REACT ON and OFF Indications Figure 5- 28 A28- 1146- 102- 00 Radar Facts 5-39
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PRIMUSr 880 Digital Weather Radar System Shadowing An operating technique similar to the REACT blue field is shadowing. To use the shadowing technique, tilt the antenna down until ground is being painted just in front of the storm cell(s). An area of no ground returns behind the storm cell has the appearance of a shadow behind the cell. This shadow area indicates that the storm cell has totally attenuated the radar energy and the radar cannot show any additional targets (WX or ground) behind the cell.
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PRIMUSr 880 Digital Weather Radar System Although penetrating a storm with a red (level three) core appears to be an acceptable risk, it is not. At the lower end of the red zone, there is no chance of extreme turbulence, a slight chance of severe turbulence, and a 40% chance of moderate turbulence. However, the radar lumps all of the rainfall rates between 12 mm to 50 mm per hour into one group - a level three (red).
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PRIMUSr 880 Digital Weather Radar System Turbulence Detection Theory The PRIMUSâ 880 Digital Weather Radar uses a turbulence detection technique called Pulse Pair Processing (PPP). The PPP technique used in the new PRIMUSâ 880 Digital Weather Radar is adapted from the proven technique used in the earlier PRIMUSâ Weather Radars. In the turbulence detection mode of operation, the PRIMUSâ 880 Digital Weather Radar transmits about 1400 pulses per second with a power of 10 kW.
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PRIMUSr 880 Digital Weather Radar System With the very short time between radar pulses when in the turbulence mode (one pulse every .0008 second), little or no turbulence results in little or no change in the size or position of the raindrops. This results in little or no change in the individual returns from each raindrop and a commensurate little or no change in the total return vector.
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PRIMUSr 880 Digital Weather Radar System Total Return Vector Figure 5- 30 AD- 17726- R1@ No Turbulence Figure 5- 31 Radar Facts 5-44 A28- 1146- 102- 00
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PRIMUSr 880 Digital Weather Radar System TURBULENT AD- 17727- R1@ Turbulent Figure 5- 32 Turbulence Detection Operation With the radar in the WX mode and with 50 miles or less range selected, pushing the TRB switch turns on the turbulence detection mode. Areas of detected turbulence are displayed in soft white, as shown in figure 5- 33. Soft white is a high contrast shade of white that has a slight gray appearance.
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PRIMUSr 880 Digital Weather Radar System Mode annunciation for the turbulence detection mode is the /T legend that is added to the WX annunciation. The resultant annunciation is WX/T for weather and turbulence. The color bar legend on the dedicated radar indicator includes a T within a soft white square whenever turbulence detection is turned on. EFIS/MFD does not have a color bar legend. The PRIMUSâ 880 Digital Weather Radar measures the motion of raindrops to determine areas of turbulence.
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PRIMUSr 880 Digital Weather Radar System INTENSITY AIRCRAFT REACTION REACTION INSIDE AIRCRAFT Turbulence that momentarily causes slight, erratic changes in altitude and/or attitude (pitch, roll, yaw). Occupants may feel a slight strain against seat belts or shoulder straps. Unsecured objects may be displaced slightly. MODERATE Turbulence that is similar to light turbulence but of greater intensity. Changes in altitude and/or attitude occur but the aircraft remains in positive control at all times.
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PRIMUSr 880 Digital Weather Radar System 100% 1/4”HAIL RELATIVE FREQUENCY 80% 60% 40% 1/2”HAIL 20% 3/4”AND LAGER HAIL 0% LEVEL 2 YELLOW LEVEL 3 RED LEVEL 4 MAGENTA AD- 15358- R1@ Hail Size Probability Figure 5- 35 Spotting Hail As previously stated, dry hail is a poor reflector, and therefore generates deceptively weak or absent radar returns. When flying above the freezing level, hail can be expected in regions above and around wet storm cells found at lower altitudes.
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PRIMUSr 880 Digital Weather Radar System On reaching the tropopause, the hail is ejected from the storm and falls downward to a point where it is sucked back into the storm. When the hail falls below the freezing level, however, it begins to melt and form a thin surface layer of liquid detectable by radar. A slight downward tilt of the antenna toward the warmer air shows rain coming from unseen dry hail that is directly in the flightpath, as shown in figure 5- 36.
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PRIMUSr 880 Digital Weather Radar System FINGER HOOK U- SHAPE AD- 35713@ Familiar Hailstorm Patterns Figure 5- 37 The more that is learned about radar, the more the pilot is an all- important part of the system. The proper use of controls is essential to gathering all pertinent weather data. The proper interpretation of that data (the displayed patterns) is equally important to safety and comfort. This point is illustrated again in figure 5- 38.
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PRIMUSr 880 Digital Weather Radar System OVERFLYING A STORM HAIL AD- 12061- R1@ Overshooting a Storm Figure 5- 38 Another example of the pilot’s importance in helping the radar serve its safety/comfort purpose is shown in figure 5- 39. This is the blind alley or box canyon situation. Pilots can find themselves in this situation if they habitually fly with the radar on the short range.
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PRIMUSr 880 Digital Weather Radar System THE BLIND ALLEY 40 20 20 LONG RANGE SHORT RANGE AD- 12062- R1@ Short- and Long- Blind Alley Figure 5- 39 Radar Facts 5-52 A28- 1146- 102- 00
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PRIMUSr 880 Digital Weather Radar System Azimuth Resolution When two targets, such as storms, are closely adjacent at the same range, the radar displays them as a single target, as shown in figure 5- 38. However, as the aircraft approaches the targets, they appear to separate. In the illustration, the airplane is far away from the targets at position A. At this distance, the beam width is spreading.
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PRIMUSr 880 Digital Weather Radar System RADOME Ice or water on the radome does not generally cause radar failure, but it hampers operation. The radome is constructed of materials that pass the radar energy with little attenuation. Ice or water increases the attenuation making the radar appear to have less sensitivity. Ice can cause refractive distortion, a condition characterized by loss of image definition.
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PRIMUSr 880 Digital Weather Radar System WEATHER AVOIDANCE Figure 5- 41 illustrates a typical weather display in WX mode. Recommended procedures when using the radar for weather avoidance are given in table 5- 12. The procedures are given in bold face, explanations of the procedure follow in normal type face.
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PRIMUSr 880 Digital Weather Radar System Step Procedure 1 Keep TGT alert enabled when using short ranges to be alerted if a new storm cell develops in the aircraft’s flightpath. 2 Keep the gain in preset. The gain control should be in preset except for brief periods when variable gain is used for detailed analysis. Immediately after the analysis, switch back to preset gain. WARNING DO NOT LEAVE THE RADAR IN VARIABLE GAIN. SIGNIFICANT WEATHER MAY NOT BE DISPLAYED.
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PRIMUSr 880 Digital Weather Radar System Step Procedure 5 When flying at high altitudes, tilt downward frequently to avoid flying above storm tops. Studies by the National Severe Storms Laboratory (NSSL) of Oklahoma have determined that thunderstorms extending to 60,000 ft show little variation of turbulence intensity with altitude. Ice crystals are poor reflectors.
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PRIMUSr 880 Digital Weather Radar System Step Procedure 9 Avoid all rapidly growing storms by 20 miles. When severe storms and rapid development are evident, the intensity of the radar return may increase by a huge factor in a matter of minutes. Moreover, the summit of the storm cells may grow at 7000 ft/min. The pilot cannot expect a flightpath through such a field of strong storms separated by 20 to 30 NM to be free of severe turbulence. 10 Avoid all storms showing erratic motion by 20 miles.
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PRIMUSr 880 Digital Weather Radar System Step Procedure Three of the most common erratic motions are: 1. Right Turning Echo. This is the most frequently observed erratic motion. Sometimes a thunderstorm echo traveling the same direction and speed as nearby thunderstorm echoes, slows, and turns to the right of its previous motion. The erratic motion may last an hour or more before it resumes its previous motion. The storm should be considered severe while this erratic motion is in progress. 2.
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PRIMUSr 880 Digital Weather Radar System Step 11 Procedure Never continue flight towards or into a radar shadow or the blue REACT field. WARNING STORMS SITUATED BEHIND INTERVENING RAINFALL MAY BE MORE SEVERE THAN DEPICTED ON THE DISPLAY. If the radar signal can penetrate a storm, the target displayed seems to cast a shadow with no visible returns. This indicates that the storm contains a great amount of rain, that attenuates the signal and prevents the radar from seeing beyond the cell under observation.
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PRIMUSr 880 Digital Weather Radar System N AD- 15560- R1@ Typical Hook Pattern Figure 5- 42 The hooks are located at the right rear side of the thunderstorm echo’s direction of movement (usually the southwest quadrant). The hook is not the tornado echo! A small scale low pressure area is centered at the right rear side of the thunderstorm echo near its edge. The low usually ranges from about 3 to 10 miles in diameter.
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PRIMUSr 880 Digital Weather Radar System There are many patterns on radar that resemble hook echoes but are not associated with severe weather. Severe weather hook echoes last at least 5 minutes and are less than 25 miles in diameter. The favored location for hook echoes is to the right rear of a large and strong cell, however, in rare cases tornadoes occur with hooks in other parts of the cell.
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PRIMUSr 880 Digital Weather Radar System AVOID PENDANT BY 20 MILES The pendant shape shown in figure 5- 44, represents one of the most severe storms - the supercell. One study concluded that, in supercells: D The average maximum size of hail is over 2 inches (5.3 cm) D The average width of the hail swath is over 12.5 miles (20.2 km) D Sixty percent produce funnel clouds or tornadoes. The classic pendant shape echo is shown in figure 5- 44.
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PRIMUSr 880 Digital Weather Radar System AVOID STEEP RAIN GRADIENTS BY 20 MILES Figure 5- 45 shows steep rain gradients. Refer to the paragraph, Interpreting Weather Radar Images, this section, for a detailed explanation of weather images.
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PRIMUSr 880 Digital Weather Radar System 50 40 30 20 10 AD- 22161- R1@ Crescent Shape Figure 5- 46 Line Configurations AVOID THUNDERSTORM ECHOES AT THE SOUTH END OF A LINE OR AT A BREAK IN A LINE BY 20 MILES The echo at the south end of a line of echoes is often severe and so too is the storm on the north side of a break in line. Breaks frequently fill in and are particularly hazardous for this reason. Breaks should be avoided unless they are 40 miles wide.
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PRIMUSr 880 Digital Weather Radar System AVOID LINE ECHO WAVE PATTERNS (LEWP) BY 20 MILES One portion of a line may accelerate and cause the line to assume a wave- like configuration. Figure 5- 47 is an example of an LEWP. The most severe weather is likely at S. LEWPs form solid or nearly solid lines that are dangerous to aircraft operations and disruptive to normal air traffic flow.
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PRIMUSr 880 Digital Weather Radar System AVOID BOW- SHAPED LINE OF ECHOES BY 20 MILES Sometimes a fast moving, broken to solid thunderstorm line will become bow- shaped as shown in figure 5- 48. Severe weather is most likely along the bulge and at the north end, but severe weather can occur at any point along the line. Bow- shaped lines are particularly disruptive to aircraft operations because they are broken to solid and may accelerate to speeds in excess of 70 knots within an hour.
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PRIMUSr 880 Digital Weather Radar System Additional Hazards TURBULENCE VERSUS DISTANCE FROM STORM CORE The stronger the return, the further the turbulence will be encountered from the storm core at any altitude. Severe turbulence is often found in the tenuous anvil cloud 15 to 20 miles downwind from a severe storm core. Moreover, the storm cloud is only the visible portion of a turbulent system whose up and down drafts often extend outside of the storm proper.
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PRIMUSr 880 Digital Weather Radar System GROUND MAPPING Ground mapping operation is selected with the GMAP button An example of ground map display is shown in figure 5- 49. Turn the TILT control down until the desired amount of terrain is displayed. The degree of down- tilt will depend upon the type of terrain, aircraft altitude, and selected range. Tables 5- 13 and 5- 5 show tilt settings for maximal ground target display at selected ranges.
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PRIMUSr 880 Digital Weather Radar System RANGE SCALE (NM) 10 25 50 100 - 12 -8 - 11 -8 - 10 -7 - 13 -9 -7 - 11 -8 -6 - 10 -7 -6 -5 200 ALTITUDE (FEET) 30,000 25,000 20,000 15,000 10,000 - 13 -8 -6 5,000 -9 -6 -5 4,000 -8 -6 -5 3,000 -7 -5 -5 2,000 -6 -5 -4 1,000 -5 -4 246 (LINE OF SIGHT LIMITED REGION) 35,000 (TILT LIMITED REGION) 40,000 LINE OF SIGHT (NM) 230 213 195 174 151 123 87 78 67 55 39 AD- 35710@ TILT Setting for Maximal Ground Target Display 12-
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PRIMUSr 880 Digital Weather Radar System RANGE SCALE (MILES) 5 10 25 50 100 200 LINE OF SIGHT (MILES) - 13 -5 -2 -1 246 - 11 -4 -1 0 230 0 213 35,000 30,000 25,000 -9 -3 -1 -7 -2 0 195 174 -5 -1 0 15,000 - 12 -3 -1 +1 10,000 -7 -1 0 +1 5,000 -7 -2 0 +1 4,000 -5 -1 +1 +2 3,000 -3 0 +1 +2 2,000 -1 +1 +2 +2 1,000 +1 +2 +2 20,000 (LINE OF SIGHT LIMITED REGION) 40,000 (TILT LIMITED REGION) ALTITUDE (FEET) 151 123 87 78 67 55 39 AD- 35711@ TI
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PRIMUSr 880 Digital Weather Radar System 6. Maximum Permissible Exposure Level (MPEL) Heating and radiation effects of weather radar can be hazardous to life. Personnel should remain at a distance greater than R from the radiating antenna in order to be outside of the envelope in which radiation exposure levels equal or exceed 10 mW/cm2, the limit recommended in FAA Advisory Circular AC No.
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PRIMUSr 880 Digital Weather Radar System 7. In- Flight Troubleshooting The PRIMUSÒ 880 Digital Weather Radar System can provide troubleshooting information on one of two formats: D Fault codes D Text faults. The selection is made at the time of installation. This section describes access and use of this information. If the fault codes option is selected, they are shown in place of the tilt angle. The text fault option provides English text in the radar test pattern areas.
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PRIMUSr 880 Digital Weather Radar System NOTES: 1. FC installations with a radar indicator can display stored faults for the current power- on cycle and nine previous cycles. Installations with radar displayed on the electronic flight instrument system (EFIS) do not display stored faults. 2. In FC installation, that use a radar indicator, when the storage memory is full, the indicator fault storage deletes the oldest power- on fault codes to make room for the newest. 3.
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PRIMUSr 880 Digital Weather Radar System Table 7- 1 describes the six fault data fields that are displayed in figure 7- 1. Field No. Description 1 Pilot Message 2 Line Maintenance Message 3 Fault Code/Power- on Code 4 Fault Name 5 Transmit ON/OFF 6 Strap Code 1. If airborne, only fault fields 1, 2, and 3 are displayed. NOTES: 2. Airborne, only the current faults are displayed. 3. Strap codes indicate the installation configuration that was done at the time of installation.
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PRIMUSr 880 Digital Weather Radar System Figure 7- 2 shows the fault codes displayed on EFIS with text faults disabled.
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PRIMUSr 880 Digital Weather Radar System Fault Code and Text Fault Relationships Table 7- 2 lists the relationship between: D Fault codes (FC) D Pilot/Maintenance Messages D Fault Name/type/description/cross reference (XREF).
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PRIMUSr 880 Digital Weather Radar System FC XREF FAULT DESCRIPTION 4828 FPGA Download FAULT NAME PILOT MSG LINE MAINT FAULT TYPE 4906 IO FPGA REG 06 4847 STC Monitor STC DAC RADAR FAIL PULL RTA POWER ON 07 4830 HVPS Monitor HVPS MON RADAR FAIL PULL RTA CONTINUOUS 4816 DSP RAM 4817 DSP Video RAM POWER ON 4855 DSP Watchdog CONTINUOUS 4900 Mailbox Miscompare 4901 DSP Holda Asserted 4902 DSP Holda not Asserted 10 DSP RADAR FAIL PULL RTA POWER ON 4825 Filament Monitor
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PRIMUSr 880 Digital Weather Radar System FC XREF FAULT DESCRIPTION FAULT NAME PILOT MSG 22 4841 Selftest OSC Failure RCVR SELF- TEST PICTURE UNCAL 4843 Multiple AFC Unlocks 4845 AFC Sweeping 24 LINE MAINT FAULT TYPE PULL RTA CONTIUOUS SPOKING LIKELY AFC CONTINUOUS PULL RTA 4929 AFC DAC Monitor 4930 AFC Trim DAC Monitor 27 4848 AHRS/IRS Source HS 429 STAB UNCAL CHK ATT SRC INSTALLATION 30 4849 DADC Source LS 429 TURB UNCAL CHK ADC INSTALLATION 33 4852 Analog Stab Ref
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PRIMUSr 880 Digital Weather Radar System Table 7- 3 describes the pilot messages. Pilot MSG RADAR FAIL Description The radar is currently inoperable and should not be relied upon. It will need to be replaced or repaired at the next opportunity. RADAR CAUTION A failure has been detected that can compromise the calibration accuracy of the radar. Information from the radar should be used only for advisory purposes such as ground mapping for navigation.
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PRIMUSr 880 Digital Weather Radar System 8. Honeywell Product Support The Honeywell SPEXR program for corporate operators provides an extensive exchange and rental service that complements a worldwide network of support centers. An inventory of more than 9,000 spare components assures that the Honeywell equipped aircraft will be returned to service promptly and economically. This service is available both during and after warranty.
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PRIMUSr 880 Digital Weather Radar System CUSTOMER SUPPORT Honeywell Aerospace Online Technical Publications Web Site Go to the Honeywell Online Technical Publications Web site at https://pubs.cas.honeywell.com/ to: D Download or view publications online D Order a publication D Tell Honeywell of a possible data error in a publication.
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PRIMUSr 880 Digital Weather Radar System 9.
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PRIMUSr 880 Digital Weather Radar System FLTPLN, FP, FPLN FMS FPGA FSBY ft Flight Management System Field--Programmable Gate Array Forced Standby Feet GCR GMAP GPS Ground Clutter Reduction Ground Mapping Global Positioning System hr HVPS hour High Voltage Power Supply INHIB IO IOP IN IRS Inhibit Input/Output Inoperative Inch Inertial Reference System kt, kts Knot(s) LEWP LSS, LX Line Echo Wave Pattern Lightning Sensor System MFD mm MON MPEL Multifunction Display millimeter Monitor Maximum Perm
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PRIMUSr 880 Digital Weather Radar System RCT, REACT RCVR RTA Rain Echo Attenuation Compensation Technique Receiver Receiver Transmitter Antenna SBY,STBY SCI SCT, SECT SECT SLV SPEX SRC STAB STC Standby Serial Control Interface Scan Sector Sector Scan Slave Spares Exchange Source Stabilization Sensitivity Timing Control TCAS TERR TGT TRB TRV TST TURB Traffic Alert and Crew Alerting System Terrain Target Turbulence Total Return Vector Test Turbulence UDI UNCAL Universal Digital Interface Uncalibration
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PRIMUSr 880 Digital Weather Radar System Appendix A Federal Aviation Administration (FAA) Advisory Circulars NOTE: This section contains a word- for- word transcription of the contents of the following FAA advisory circulars: D AC 20- 68B D AC 00- 24B. SUBJECT: RECOMMENDED RADIATION SAFETY PRECAUTIONS FOR GROUND OPERATION OF AIRBORNE WEATHER RADAR Purpose This circular sets forth recommended radiation safety precautions to be taken by personnel when operating airborne weather radar on the ground.
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PRIMUSr 880 Digital Weather Radar System Background Dangers from ground operation of airborne weather radar include the possibility of human body damage and ignition of combustible materials by radiated energy. Low tolerance parts of the body include the eyes and the testis. Precautions Management and supervisory personnel should establish procedures for advising personnel of dangers from operating airborne weather radars on the ground.
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PRIMUSr 880 Digital Weather Radar System D Personnel should be advised that when high power radar transmitters are operated out of their protective cases, X- rays may be emitted. Stray X- rays may emanate from the glass envelope type pulser, oscillator, clipper, or rectifier tubes, as well as magnetrons. COMBUSTIBLE MATERIALS To prevent possible fuel ignition, an insulated airborne weather radar should not be operated while an aircraft is being refueled or defueled. M.C. Beard Director of Airworthiness.
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PRIMUSr 880 Digital Weather Radar System SUBJECT: THUNDERSTORMS Purpose This advisory circular describes the hazards of thunderstorms to aviation and offers guidance to help prevent accidents caused by thunderstorms. Cancellation Advisory Circular 00- 24A, dated June 23, 1978, is cancelled. Related Reading Material Advisory Circulars, 00- 6A, Aviation Weather, 090- 45B, Aviation Weather Services, 00- 50A, Low Level Wind Shear. General We all know what a thunderstorm looks like.
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PRIMUSr 880 Digital Weather Radar System TORNADOES D The most violent thunderstorms draw into their cloud bases with great vigor. If the incoming air has any initial rotating motion, it often forms an extremely concentrated vortex from the surface well into the cloud. Meteorologists have estimated that wind in such a vortex can exceed 200 knots; pressure inside the vortex is quite low.
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PRIMUSr 880 Digital Weather Radar System ICING D Updrafts in a thunderstorm support abundant liquid water with relatively large droplet sizes; and when carried above the freezing level, the water becomes supercooled. When temperature in the upward current cools to about - 15 _C, much of the remaining water vapor sublimates as ice crystals; and above this level, at lower temperatures, the amount of supercooled water decreases. D Supercooled water freezes on impact with an aircraft.
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PRIMUSr 880 Digital Weather Radar System HAIL D Hail competes with turbulence as the greatest thunderstorm hazard to aircraft. Supercooled drops above the freezing level begin to freeze. Once a drop has frozen, other drops latch on and freeze to it, so the hailstone grows - sometimes into a huge iceball. Large hail occurs with severe thunderstorms with strong updrafts that have built to great heights. Eventually, the hailstones fall, possibly some distance from the storm core.
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PRIMUSr 880 Digital Weather Radar System LIGHTNING A lightning strike can puncture the skin of an aircraft and can damage communication and electronic navigational equipment. Lightning has been suspected of igniting fuel vapors causing explosion; however, serious accidents due to lightning strikes are extremely rare. Nearby lightning can blind the pilot rendering him momentarily unable to navigate by instrument or by visual reference.
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PRIMUSr 880 Digital Weather Radar System Airborne weather avoidance radar is, as its name implies, for avoiding severe weather - not for penetrating it. Whether to fly into an area of 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 avoidance turbulence.
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PRIMUSr 880 Digital Weather Radar System If you cannot avoid penetrating a thunderstorm, the following are some do’s BEFORE entering the storm. D Tighten your safety belt, put on your shoulder harness if you have one, and secure all loose objects. D Plan and hold your course to take you through the storm in a minimum time. D To avoid the most critical icing, establish a penetration altitude below the freezing level or above the level of - 15 _C.
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PRIMUSr 880 Digital Weather Radar System National Severe Storms Laboratory (NSSL) Thunderstorm Research The NSSL has, since 1964, been the focal point of our thunderstorm research. In- flight conditions obtained from thunderstorm penetration by controlled, especially equipped high performance aircraft are compared by the NSSL with National Weather Service (NWS) type ground- based radar and with newly developed doppler radar.
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PRIMUSr 880 Digital Weather Radar System TURBULENCE IN RELATION TO DISTANCE FROM THE STORM EDGE THE CLEAR AIR ON THE INFLOW SIDE OF A STORM IS A PLACE WHERE SEVERE TURBULENCE OCCURS. At the edge of a cloud, the mixing of cloudy and clear air often produces strong temperature gradients associated with rapid variation of vertical velocity.
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PRIMUSr 880 Digital Weather Radar System MAXIMUM STORM TOPS Photographic data indicates that the maximum height attained by thunderstorm clouds is approximately 63,000 feet. Such very tall storm tops have not been explored by direct means, but meteorological judgments indicate the probable existence of large hail and strong vertical drafts to within a few thousand feet of the top of these isolated stratosphere- penetrating storms.
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PRIMUSr 880 Digital Weather Radar System EXTRAPOLATION TO DIFFERENT CLIMBS General comment: Severe storms are associated with an atmospheric stratification marked by large values of moisture in low levels, relative dryness in middle levels, and strong wind shear. It is well known that this stratification of moisture permits excessive magnitudes of convective instability to exist for an indefinite period until rapid overturning of air is triggered by a suitable disturbance.
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PRIMUSr 880 Digital Weather Radar System Appendix B Enhanced Ground--Proximity Warning System (EGPWS) The Mark VII EGPWS combines information from aircraft navigation equipment (i.e., flight management system (FMS), inertial reference system (IRS), global positioning system (GPS), radio altimeter) with a stored terrain database that alerts the pilot to potentially dangerous ground proximity. In addition to the verbal alert, the EGPWS can display the terrain data on the weather radar indicator.
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PRIMUSr 880 Digital Weather Radar System PUSH BUTTON CONTROLS The following remotely mounted push buttons control the EGPWS display: D INHIB (Inhibit) Button -- When active, the push on/push off INHIB button prevents terrain data from being displayed on the radar indicator. When the button is active, the INHIB annunciator lights. D ON (Terrain) Button -- When active, the push on/push off ON button displays terrain on the radar indicator.
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PRIMUSr 880 Digital Weather Radar System Related EGPWS System Operation Some installations may have a DATA--NAV (navigation display, and/or checklist), lightning sensor system (LSS), and/or traffic alert and crew alerting system (TCAS) that already share the radar indicator’s display by way of the Universal Digital Interface (UDI) connector. These systems have priority for access to the radar display screen.
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PRIMUSr 880 Digital Weather Radar System EGPWS Display The EGPWS displays is shown as variable dot patterns in green, yellow, or red. The density and color is a function of how close the terrain is relative to the aircraft altitude above ground level (AGL), refer to table B--1. Terrain/obstacle alerts are shown by painting the threatening terrain as solid or red. Terrain that is more than 2000 feet below the aircraft is not displayed. Areas where terrain data is not available are shown in magenta.
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PRIMUSr 880 Digital Weather Radar System Figure B--1 shows the EGPWS over KPHX airport at 2000 feet mean sea level heading north. The terrain shows the mountains to the north of Phoenix.
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PRIMUSr 880 Digital Weather Radar System EGPWS Test When the EGPWS is selected for display, it can be tested. Push the remote mounted EGPWS TEST button to display the test format shown in figure B--2.
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PRIMUSr 880 Digital Weather Radar System Index A Abbreviations, 9-1 Accelerative error, 5-18 Altitude compensated tilt, 5-16 C Categorizing storms, 5-35 D Dynamic error, 5-18 F Federal Aviation Administration (FAA) Advisory Circulars recommended radiation safety precautions for ground operation of airborne weather radar, A--1 background, A--2 cancellation, A--1 precautions, A--2 purpose, A--1 related reading material, A--1 thunderstorms, A--4 general, A--4 hazards, A--4 national severe storms laboratory
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PRIMUSr 880 Digital Weather Radar System Index (cont) I power--up procedure, 4-1 radar mode ---- ground mapping, 4-6 radar mode ---- weather, 4-4 standby, 4-4 test mode, 4-6 color bands, 4-7 dedicated radar indicator, 4-7 fault code, 4--7 EFIS/MFD/ND, 4-7 noise band, 4-6 target alert block, 4-6 text fault, 4--6 In--flight troubleshooting, fault access fault data fields, 7-3 pilot messages, 7-5 test mode with TEXT FAULTS enabled, 7-2 text faults, 7-5 Interpreting weather radar images, 5-31 N National sev
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PRIMUSr 880 Digital Weather Radar System Index (cont) range, 3-18 SECT (scan sector), 3-16 SLV (slave), 3-19 STB (stabilization), 3-17 TGT (target), 3-16 Tilt, 3-16 TRB (turbulence detection), 3-17 WI--880 Weather radar indicator operation, 3-1 AZ (azimuth), 3-8 BRT (brightness) or BRT/LSS (lightning sensor system), 3-9 display area, 3-2 function switch, 3-3 gain, 3-10 range, 3-8 RCT (rain echo attenuation compensation technique), 3-7 SCT (scan sector), 3-8 STAB (stabilization), 3-7 target alert characteri
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PRIMUSr 880 Digital Weather Radar System Index (cont) Radar facts (cont) rain echo attenuation compensation technique (REACT), 5-37 azimuth resolution, 5-53 hail size probability, 5-47 shadowing, 5-40 spotting hail, 5-48 turbulence detection operation, 5-45 turbulence detection theory, 5-42 turbulence probability, 5-40 stabilization, 5-18 accelerative error, 5-18 dynamic error, 5-18 tilt management, 5-5 variable gain control, 5-37 weather avoidance, 5-55 severe weather avoidance procedures, 5-60 weather di
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PRIMUSr 880 Digital Weather Radar System Index (cont) National severe storms laboratory (NSSL) thunderstorm research, A--11 extrapolation to different climbs, A--14 hail in thunderstorms, A--13 maximum storm tops, A--13 modification of criteria when severe storms and rapid development are evident, A--13 relationship between turbulence and altitude, A--11 relationship between turbulence and reflectivity, A--11 turbulence above storm tops, A--12 turbulence and echo intensity on NWS radar (WSR--57), A--11 tur
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PRIMUSr 880 Digital Weather Radar System Index (cont) Weather radar controller operation (cont) OFF, 3-13 Rainfall rate color coding, 3-13 RCT (rain Echo attenuation compensation technique), 3-13 SBY (standby), 3-13 TST (test), 3-15 WX (weather), 3-13 tilt, 3-16 PULL ACT (altitude compensated tilt) function, 3-16 WI--880 Weather radar indicator operation, 3-1 BRT (brightness) or BRT/LSS (lightning sensor system), 3-9 CLR/TST (clear/test), 3-9 LX (lightning sensor system), 3-9 OFF, 3-9 SBY (standby) , 3-9 f