i.e. from 0 to 320 NM. The 6-micros wide pulse echo is processed for ranges from 0 to 20 NM. The 18-micros wide pulse echo is processed for ranges greater than 40 NM. The 6-micros and 18-micros pulse echoes are processed for ranges between 20 and 40 NM
-
in the turbulence mode (HIGH PRF), the HIGH PRF and LOW PRF pulses are interlaced. This causes simultaneous WX/MAP and TURBULENCE information. The 6-micros wide pulses 1 to 9 are transmitted at 1600 Hz and are used for turbulence detection. The 18-micros wide pulse 10 is used for the WX/MAP mode. The high frequency of the PRF required for turbulence detection (1600 Hz) limits the range of this detection to 40 NM.
-
in windshear mode (VERY HIGH PRF) the 1.5-micros wide pulses are transmitted at 6000 Hz. The sequence of transmitted RF pulses consists of two staggered pulse trains, each with the different carrier frequency. Each pulse train has a PRF of 3000 Hz, providing 10 NM (minimum selected range on EFIS control section).
R **ON A/C 051-099, 106-149, 201-299, 301-399, 401-499,
B. Timing of Transmitted Pulses in WX/MAP Mode, in Doppler Mode (Turbulence) and in W/S Mode (Ref. Fig. 010A)
-
in WX and MAP modes, at short ranges (less than or equal to 60NM) the period of pulse (four) transmission-reception is 5.6 ms. This causes an interrogation frequency (PRF) of 1280 Hz. For medium ranges (greater than 60NM and less than or equal to 165 NM), the period of pulse (two) transmission-reception is 8.4 ms at a PRF of 360 Hz. For ranges greater than 165 NM, the period of pulse (two) transmission-reception is 8.4 ms at a PRF of 240 Hz.
-
in the turbulence mode (High PRF), the PRF is increased from 240 to 1280 pulses per second. The threshold of turbulent targets is precipitation velocities of 5 m/s. This threshold translates into a Doppler frequency shift of 312,5Hz. It explains the increased PRF.
1EFF : ALL 1 34-41-00Page 51 1 1 Config-3 Aug 01/05 1 1 1CES 1
Weather radar - Pulse Transmission Timing Diagram
Figure 010
R 1EFF : 001-049, 101-105, 151-199, 1 34-41-00Page 52 1 1 Config-3 May 01/05 1 1 1CES 1
Weather radar - Pulse Transmission Timing Diagram
Figure 010A
R 1EFF : 051-099, 106-149, 201-299, 301-399, 1 34-41-00Page 53 1401-499, 1Config-3 Aug 01/05 1 1 1CES 1 With this high PRF rate, the maximum range for turbulence detection is approximately 56 NM.
-in the windshear mode (Very High PRF), 64 pulses are transmitted during a period of 23 ms. The PRF is 3000 Hz.
**ON A/C ALL
C. Controls and Indicating The various system controls are grouped on the weather radar control unit and on the EFIS control sections of the FCU. Radar image control on the NDs is achieved through the scale selector switches located on the Captain and First Officer EFIS control sections of the FCU.
**ON A/C 001-049, 101-105,
(1) Weather radar control unit (Ref. Fig. 011) The face of the control unit is provided with integral lighting. The INTEG LT/ MAIN PNL & PED potentiometer enables lighting adjustment. The potentiometer is located on the panel 111VU, at the left aft section of the center pedestal 11VU. The face of the weather radar control unit includes the following controls:
(a)
A switch, item 1, with two stable positions OFF/ON, which enables the activation of the transceiver.
(b)
A mode selector switch, item 2, which enables the selection of the WX, WX/TURB or MAP function.
(c)
A TILT selector switch, item 3, which enables the control of the antenna elevation. Antenna position is read in degrees, opposite the notch on the switch:
-either from 0 to 15 deg. upwards (UP) - or from 0 to 15 deg. downwards (DN).
(d)
A GAIN potentiometer, item 5, which enables the manual adjustment of the transceiver gain.
(e)
A WINDSHEAR switch, item 4, with two stable positions AUTO/OFF, which enables the selection of the windshear function.
(f)
Not Applicable
1EFF : ALL 1 34-41-00Page 54 1 1 Config-3 Aug 01/05R 1 1 1CES 1
Weather Radar - Control Unit
Figure 011
R 1EFF : 001-049, 101-105, 1 34-41-00Page 55 1 1 Config-3 May 01/05 1 1 1CES 1R **ON A/C 051-099, 106-149, 201-299, 301-399, 401-499,
(1) Weather radar control unit (Ref. Fig. 011A) The face of the control unit is provided with integral lighting. The INTEG LT potentiometer enables lighting adjustment. The potentiometer is located on the panel 111VU, at the left aft section of the center pedestal 100VU. The face of the weather radar control unit includes the following controls:
(a)
A switch, item 6, with three stable positions 1/OFF/2, which enables the activation of the transceiver.
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