EFFECTIVITY
LH 001-003 CONFIG 4
IB 405799 Page 2
34-33-00
Apr 25/88
SEE E
TRANSMIT
LRRA R/T UNITS
ANT NO. 1 SEE C
RECEIVE ANT NO. 1
RECEIVE TRANSMIT
ANT NO. 2 CENTER
ANT NO. 3 INSTRUMENT PANEL TRANSMIT
SEE D ANT NO. 2
RECEIVE ANT NO. 3
R/T NO. 3
R/T NO. 2
R/T NO. 1
LRRA-3
LRRA-3 FAILURE ANNUNCIATOR BLACK-VALID RED-INVALID
AFT CENTER EQUIPMENT CENTER ANNUNCIATOR MODULE
C D
MOVABLE
DH INDEX
POINTER
MASK WARNING
DH FLAG
DH LIGHT 0
20 20 25 1
10 10 20
F X 100 F T
5 5
15
S 10 5 10 5 10 RADIO 3
20 20 RISING ALT. 4
TEST RUNWAY 5
TEST TEST DH INDEX
BUTTON CONTROL KNOB
ATTITUDE DIRECTOR INDICATOR HEIGHT INDICATOR
E
Low Range Radio Altimeter System Component Location Figure 1 (Sheet 2)
EFFECTIVITY
CONFIG 4 LH 004-099799 Page 3
34-33-00
Apr 25/88
AIRPLANES INCORP SB 34-2069
LRRA System Block Diagram
Figure 2 (Sheet 1)
EFFECTIVITY
CONFIG 4 LH 001-003; IB 405
799 Page 4
34-33-00
Apr 25/88
LRRA System Block Diagram
Figure 2 (Sheet 2)
EFFECTIVITYCONFIG 4 LH 004-099
799 Page 5
34-33-00
Apr 25/88
B. The warning flag appears and covers the dial in the vicinity of the 100-foot indication when a malfunction occurs in the system. The altitude pointer is driven underneath the pointer mask at altitudes above 2500 feet and when a malfunction occurs in the system. The decision height (DH) control knob adjusts the position of the DH index on the altitude scale thereby selecting the altitude at which the DH light(s) operates. Self test of LRRA system No. 1 (LRRA-1, Captain's) and LRRA system No. 2 (LRRA-2, F/O's) is initiated by pressing the TEST switch at the associated height indicator.
C. On IB airplanes, a vertical scale height indicator (HI) is located on each pilot's flight instrument panel and provides a visual display of airplane terrain clearance. Airplane altitude is displayed by a servo-driven tape containing a calibrated scale that is read against a stationary airplane reference symbol. The tape indicates altitudes from 0 feet to 2500 feet.
D. The operating controls and indicators on the vertical scale HI consist of the following: DH index set/push-to-test control knob, decision height (DH) value counter, DH index tape, DH stationary reference, servo driven altitude tape which is read against a stationary airplane reference symbol, and a warning flag. Upper limit of the DH numerical counter is 499 feet. The altitude tape (scale) is graduated in feet and is black above 2500 feet and striped below zero feet. Self test of LRRA system No. 1 (LRRA-1, Captain's) and LRRA system No. 2 F/O's) is initiated by pressing the SET/TEST control knob at the associated HI.
5. ADI Displays
____________
A. A DH light is located on each pilot's ADI. The operation of the DH light is controlled by the height indicator located on the same instrument panel. The DH light has a press-to-test (for light burnout) feature.
B. The rising runway symbol displays both radio altitude and localizer deviation. Radio altitude is presented by the distance between the top edge of the runway symbol and the base of the fixed airplane symbol. Localizer deviation is presented by the runway symbol moving left or right across a horizontal scale (Ref 34-31-00).
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