How To Use The Primus 660 Weather Radar

HOW TO USE THE PRIMUS® 660 WEATHER RADAR

CONTENTS A. INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 B. RADAR SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 C. INTERPRETING WX RADAR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 D. DESCRIPTION PRIMUS 660 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 E. WEATHER RADAR CONTROL PANEL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 F. TILT MANAGEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

VERSION 1.0

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A. INTRODUCTION This brochure aims to provide the operator with essential knowledge about the use of the Primus® 660 weather radar by Honeywell. This brochure is based on the Primus® 660 pilot’s manual written by Honeywell. The purpose of the weather radar is to detect storm activity along the route. After interpreting the weather radar information, pilots may decide on a new course to avoid the storm, to divert to an alternate airport or to hold on a waypoint. This brochure addresses the ATR 42/72-500 MOD 5016* and the ATR 42/72-600. Should you find any discrepancy between the ATR operational documentation and this brochure, the information contained in the ATR Flight Crew Operating Manual (FCOM) and/or Honeywell manual (Primus® 660 Digital weather radar system Pilot’s manual) shall prevail.

The ATR flight-ops support

(*) MOD 5016: Navigation - Install weather radar type PRIMUS® 660

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B. RADAR SYSTEM The radar system sends out short bursts of electromagnetic energy (X-band) that travel through space as radio waves. When these energy waves strike a target, some of the energy reflects back to the radar receiver. Thanks to the Doppler effect, electronic circuits measure the elapsed time between transmission and reception of the echo to determine the distance to the target (range). Intensity of precipitation is calculated using radar echo returns that are proportional to droplet size (small droplets will return fewer echoes whereas heavy droplets will return the majority of radar waves). Reflectivity of precipitation also depends on the type of precipitation. Dry precipitation* will return fewer echoes than precipitation with a high water content. (*) For example, dry snow is less dense than wet snow; therefore, it is less sticky.

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C. INTERPRETING WEATHER RADAR During flight preparation, the crew analyzes the weather forecast and the radar images to determine the best route to avoid hazardous weather. They also take the wind direction is into consideration, to predict the movement direction of the squall line. In flight, the WX radar will help the crew to adapt the route according to actual weather conditions. The WX radar can detect water in liquid form. Radar does not detect turbulence and dry hail (exception in the table below). NOTE: The presence of ice or water on the radome does not generally cause radar failure, but it hampers its operation. Ice or water on the radome increases the attenuation, making the radar appear less sensitive. RADAR REFLECTS

RADAR does NOT REFLECT

RAIN

VAPOR

WET HAIL & SNOW

ICE CRISTALS

DRY HAIL (very poor reflection – diameter above 1 inch / 2.54 cm)

DRY HAIL (diameter below 1 inch / 2.54 cm)

Basically, the radar detects and displays RAIN. Looking at a thunderstorm, the echoes will grow progressively larger and sharper in the middle. The darkest area is the most dangerous zone that must be avoided by pilots.

AREAS OF MAXIMUM TURBULENCE DECAYING CELLS

GROWING CELLS

MATURE CELLS

OUTLINE OF RAIN AREA VISIBLE TO RADAR BEST DETOUR

AD–12058–R1@

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EFIS (42/72-500) – Example of new route

New route to avoid hazardous weather

The stronger the echo return, the further the turbulence is encountered from the storm core at any altitude. Severe turbulence is often encountered 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 with up and down drafts that often extend outside of the storm.

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D. PRIMUS 660® DESCRIPTION The PRIMUS® 660 WX radar system is an X-band digital radar for weather detection (WX) and ground mapping (GMAP). The weather radar system detects atmospheric disturbances and provides the crew with a display of precipitation levels for ranges up to 300 NM in front of the aircraft. The system is composed of a Receiver Transmitter Antenna (RTA – 18-inch diameter), a WX radar control panel and radar displays (EFIS, -500 version or MFD -600 version). - ATR 42/72-500 MOD 5016: with a single WX radar control panel, both CPT/FO radar displays are identical. - ATR 42/72-600: with a single WX radar control panel, both CPT/FO displays are identical but pilots can select a different range using the EFCP.

Receiver Transmitter Antenna

EFCP

WX radar Control panel ATR 42/72-500

EFIS CPT/FO

WX radar Control panel ATR 42/72-600

MFD CPT/FO

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E. WEATHER RADAR CONTROL PANEL Controller ATR 42/72-500

2

4

1

5

6

7

8

3

Controller ATR 42/72-600

1

- RADAR

OFF: turns off the radar system SBY: transmitter and antenna scan are inhibited. - ATR 42/72-500 MOD 5016: STBY (green) is displayed on the EFIS. - ATR 42/72-600: WX STBY (white) is displayed on the MFD. If necessary, the radar is ready to be used. This function must be activated before each flight regardless of the weather forecast. NOTE: During ground operations and taxi, pilots must switch the Radar selector to SBY to ensure safety for ground personnel. WX: Weather detection is fully operational. - ATR 42/72-500 MOD 5016: WX (green) is displayed on the EFIS - ATR 42/72-600: WX TX (green) is displayed on the MFD If WX is selected before the initial RTA warm-up period (45 to 90 seconds), WAIT is displayed on the EFIS/MFD. In weather mode, the GAIN is preset (refer to paragraph E-4-GAIN).

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ARC mode

EFIS (ATR 42/72-500)

ROSE mode

MFD (ATR 42/72-600)

GMAP: Ground Mapping The GMAP position allows the radar to detect ground obstacles. - ATR 42/72-500 MOD 5016: GMAP (green) is displayed on the EFIS - ATR 42/72-600: WX GMAP (blue) is displayed on the MFD If GMAP is selected before the initial RTA warm-up period (45 to 90 seconds), WAIT is displayed on the EFIS/MFD. NOTE: - REACT or TARGET modes cannot be selected in GMAP mode. (refer to paragraphs E-5-RCT and E-7-TGT). - Do not use GMAP mode for weather detection. COLOR

LEVEL OF REFLECTION

Black

No return

Cyan

Least return

Yellow

Moderate return

Magenta

Strong return

Pilots can manually decrease the gain to eliminate unwanted clutter. With experience, pilots can interpret the color display patterns that indicate water regions, coastlines, hilly or mountainous regions. A good learning method is to practice ground-mapping during flights in clear visibility where the radar display can be visually compared with the terrain.

EFIS (ATR 42/72-500) 9

FP: Flight Plan (available only on -500 version) The FP position allows the radar controller to select a very long range for display (500 and 1000 NM). FPLN (green) is displayed on the EFIS. In FP mode, WX mode is not displayed. However, TGT mode can be selected (refer to paragraph E-7-TGT). In this case, FPLN and TGT (green) are displayed on the EFIS. The radar is set to detect hazardous weather within 5 to 55 miles, 7.5° on each side of aircraft heading. The target alert changes from green armed to amber TGT to alert pilots that hazardous weather has been detected in the flight path. Pilots must then select WX mode to view it.

EFIS (ATR 42/72-500)

TEST: test mode The TEST position allows specific test patterns with the following items. Color Bands: a series of black/green/yellow/red/cyan/white/magenta/blue bands, indicates that the signal to color conversion circuits are operating normally. Maintenance function: Text or Code Fault is displayed. EFIS/MFD: fault is shown on the display (TEST or WX TEST) NOTE: In test mode, the transmitter is switched ON and is radiating. ATR recommends referring to the Honeywell manual (Maximum Permissible Exposure Level) before using TEST mode.

2

- RANGE

Two buttons (up and down) are used to select the range to be displayed. ATR 42/72-500 MOD 5016 - Weather mode (WX): ranges from 2.5 to 300 NM (5 / 10 / 25 / 50 / 100 / 200 / 300 NM) - Flight Plan mode (FP): additional ranges are available (500 and 1000 NM). The same range is displayed on both EFIS. ATR 42/72-600 Range is selected from the EFCP Nav box on the pedestal, - Weather mode (WX): from 2.5 to 320 NM (5 / 10 / 20 / 40 / 80 / 160 / 320 NM) Two independent ranges can be displayed on each MFD.

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3

- TILT

The tilt knob is a rotary control that is used to select the tilt angle of the RTA beam in relation to the horizon from 15° down to 15° up. ATR recommends adjusting the tilt button frequently to scan below and above flight level to avoid flying within thunderstorms. On version -500, the tilt angle is not displayed on the EFIS. On version -600, the tilt angle is displayed on the MFD (on the bottom right in blue).

MFD (ATR 42/72-600)

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4

- GAIN

When the GAIN rotary control is pushed, the system activates the preset calibrated gain mode. Rainfall Rate

COLOR

LEVEL

No return

Black

No detectable cloud

.04 - .16

1-4

Green

Moderate storm

.16 - .47

4 - 12

Yellow

Less severe storm

.47 - 2

12 - 50

Red

Strong storm

in/hr*

mm/hr**

No return

>2 > 50 Magenta Intense storm When the GAIN rotary control is pulled, the system activates the variable gain mode. Variable gain mode is useful for additional weather avoidance. In WX mode, increasing the receiver sensibility makes it possible to view weak targets and decreasing the receiver sensibility makes it possible to eliminate weak returns. - ATR 42/72-500 MOD 5016: VAR (amber) is displayed on the EFIS - ATR 42/72-600: G-VAR (green) is displayed on the MFD * inches/hour ** millimeters/hour NOTE: Low variable gain settings may eliminate hazardous targets from the display.

EFIS (ATR 42/72-500)

12

MFD (ATR 42/72-600)

5

- RCT - Rain echo attenuation Compensation Technique (REACT)

When RCT is selected, RCT (green) is displayed on the EFIS/MFD. RCT is a submode of WX mode that automatically uses preset Gain, with the following functions switched ON: - Attenuation compensation When the radar energy goes toward heavy rain, it could result in a phenomenon known as “shadowing” or “attenuation”. Storms (heavy rain) can totally attenuate the radar energy making it impossible to detect the weather behind the first storm cell. With attenuation compensation, the cell behind the first storm cell remains properly calibrated to facilitate long-range weather detection. - Cyan REACT field The receiver gain is adjusted to maintain target calibration based on the attenuation compensation. A high attenuation level could cause the receiver to reach its maximum gain value. In this case, the weather target can no longer be calibrated. This is highlighted by replacing the background field from black to cyan. The cyan area should be avoided. To be conservative, any target detected inside a cyan area is automatically forced to a magenta color (maximum severity).

EFIS (ATR 42/72-500)

MFD (ATR 42/72-600)

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6

- STAB

The STAB button is used to activate/deactivate the pitch and roll stability (ON and OFF buttons). The purpose is to stabilize the antenna (relative to the earth’s surface) regardless of aircraft bank and pitch. The stabilization system uses the aircraft attitude source as a reference. For further information, please refer to the Honeywell manual (Stabilization). ATR does not recommend that flight crews use this function without having studied the Honeywell manual. FSBY mode: Forced Standby FSBY mode is a safety feature that inhibits the RTA on the ground to avoid X-band microwave radiation hazard, thanks to the Weight-On-Wheels inhibition. FSBY is an automatic, non-selectable mode. Pilots can override FSBY mode, by pushing the STAB button 4 times within 3 seconds. To restore FSBY mode, pilots have to pull the tilt control out, push it in, pull it out, and push it in within 3 seconds (refer to paragraph E-3-TILT) Take the following precautions if the radar system is operated in any mode other than standby or forced standby while the aircraft is on the ground: - The nose of the aircraft must be directed so the antenna scan sector is free of large metallic objects, such as hangars or other aircraft for a minimum distance of 30 meters (100 feet), and tilt the antenna fully upwards. - Do not operate the radar system during aircraft refueling or during refueling operations within 30 meters (100 feet). - Do not operate the radar if personnel are standing too close to the 120° forward sector of aircraft. For further information, please refer to the Honeywell manual (Maximum Permissible Exposure Level).

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7

- TGT

When TGT is selected, the target alert monitors beyond the selected range and within 7.5° on each side of the aircraft heading. The target alert changes from green armed to amber TGT to alert pilots that hazardous weather is detected beyond the selected range. The target alert is inactive within the selected range. Selecting TGT forces the system to preset gain. TGT can only be selected in WX or FP mode (-500 version only).

Selected Range (NM) 5 10 25 50 100 200 300 FP (Fight Plan)

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Target Range (NM) 5-55 10-60 25-75 50-100 100-150 200-250 N/A 5-55

- SECT

When SECT is selected, the normal scan sector (12 looks/minute on 120°) is replaced by a faster scan (24 looks/minutes on 60°).

EFIS (ATR 42/72-500)

MFD (ATR 42/72-600)

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F. TILT MANAGEMENT Pilots can use tilt management techniques to minimize ground clutter when viewing weather targets. The crew must adjust the tilt when airborne so that the ground will not interfere with the weather targets. If the ground target is displayed, the tilt angle has to be moved upward by 1° increments until the ground target disappears.

Elevation in feet

Z ZERO TILT

7,400 FT

25,000

29,000 FT

14,800 FT

CENTER OF RADAR BEAM

14,800 FT

15,000

5.6°

10,000

29,000 FT

7,400 FT

5,000 5 000 0

0

25

50

100

Range Nautical Miles

ZERO – RADAR (18 –Radiator) inch Radiator) ZERO TILT TILT – RADAR BeamBeam (18 – inch Honeywell manual Honeywell manual

ANTENNA ADJUSTED FOR 2.8° UPTILT

Elevation in feet

30,000 14,800 FT 20,000

CEN

3,000 FT

AM

E DAR B

7,400 FT

5.6°

10,000

F RA TER O

14,800 FT

7,400 FT

5,000 0

3,000 FT 0

10

20

30

40

50

60

Range Nautical Miles

2.8° UPTILT – Low altitude RADAR Beam (18 – inch Radiator) 2.8° UPTILT – Low altitude RADAR Beam (18 – inch Radiator) Honeywell manual Honeywell manual

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70

80

RANGE SCALE (MILES)

5

10

200

50

100

-7

-2

0

195

20,000 15,000 10,000

(TILT LIMITED REGION)

ALTITUDE (FEET) 25,000

LINE OF SIGHT (MILES)

25

-5

-1

0

174

-12

-3

-1

+1

151

-7

-1

0

+1

123

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

87 LINE OF SIGHT (MILES)

78 67 55 39

Approximate Tilt setting for minima ground target display (18­— inch Radiator) Honeywell manual NOTE: Atmospheric conditions and terrain can offset the line of sight. The main issue with weather radar use is that a 3D environment is displayed in a 2D view on the EFIS/ MFD. Because of this, the display may not represent cells at aircraft level. As a result, the antenna tilt has to be adjusted during the flight to ensure optimum detection and visualization of weather.

If the tilt is not used properly, pilots could misinterpret the weather target displayed on the EFIS/MFD. This is because reflectivity is less above freezing level and decreases gradually above freezing. If the tilt management is not appropriate, pilots could inadvertently minimize convective thunderstorms.

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Moving toward the storm

EXAMPLE OF THE AIRCRAFT FREEZING LEVEL AT CRUISING FLIGHT LEVEL

Tilt below Freezing level – Good reflectivity

Moving toward the storm

FREEZING LEVEL

CHANGE in TILT position

Tilt below Freezing level – Good reflectivityMoving toward the storm FREEZING LEVEL

FREEZING LEVEL

Tilt below Freezing level – Good reflectivity

CHANGE in TILT position NO CHANGE in TILT position

CHANGE in TILT position

FREEZING LEVEL

FREEZING LEVEL

The Thunderstorm appears to weaken as the aircraft approaches it. Above Freezing level – Bad reflectivity

FREEZING LEVEL

Proper tilt management demands that tilt bechanged continually when approaching hazardous weather.

NO CHANGE in TILT position

The following rule of thumb for tilt management could be used: 1° decrement (down) provides 100 ft down per 10 NM 18

FREEZING LEVEL

NO CHANGE in TILT position

GLOSSARY C P T Captain E F C P EFIS Control Panel E F I S Electronic Flight Instrument System F CO M Flight Crew Operating Manual FO First Officer F P Flight Plan (selectable mode on controller panel except -600 version) F P L N Flight Plan (display when mode is selected except -600 version) F S B Y Forced Stand-by

G M A P Ground Mapping M F D Multi Function Display N / A Not Applicable R C T Rain echo attenuation Compensation Technique RTA Receiver Transmitter Antenna S E C T Sector STA B Stability (pitch and roll) ST B Y Stand-by TGT Target VA R Gain Variation WX Weather detection mode

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