(o)
On test set, position REPLY/SLS switch to 100% position. Test set meter now indicates reply rate as a percentage of interrogation rate, with full scale of 100%.
NOTE: A properly operating trnasponder must reply with a rate
____ of 90% or greater.
EFFECTIVITY AF ALI ALL; DLH ALL; IBE ALL;
AF SAB ALL; AF, AT,MD, GN, AF AND VM WITHOUT AEB 34-587 CONFIG 1 AF AND 34-607 02 A Page 506
Oct 25/96
34-53-00
(p) To check SLS circuits of transponder, position test set REPLY/SLS switch to 10%/0 dB. The meter, with full scale equal to 10%, should read 1.3% or less for a properly operating transponder. Note test set display extinguishes, indicating transponder is not replying to interrogations.
CAUTION: SOME TRANSPONDERS, WHEN RECEIVING A SIGNAL NEAR MTL
_______ (MINIMUM TRIGGERING LEVEL), MAY TRANSMIT A REPLY EVEN THOUGH SLS PULSE IS PRESENT IN INTERROGATION. IF A REPLY IS RECEIVED WITH SLS PULSE AT 0 DB, REPEAT SLS TEST WITH TEST SET PLACED CLOSER TO TRANSPONDER ANTENNA TO INCREASE SIGNAL STRENGTH.
(q) Position test set SLS switch to -9 db and READOUT switch to PILOT. Note presence of ATC code and framing pulses in display.
(4) Perform altitude reporting tests as follows:
WARNING: REFER TO PRECAUTIONS IN AMM CHAPTER 34-11-00, PAGE 501
_______ PRIOR TO OPERATING PITOT-STATIC EQUIPMENT FOR THESE TESTS.
(a)
Position controls on test set as follows:
1) RCVR SENS - 65
2) REPLY/SLS - LEVEL
3) 1090 MHz - 0
(b)
On ATC control panel, select ALT RPTG and altitude source.
(c)
Connect pitot static test kit to appropriate PITOT/STATIC systems.
(d)
Adjust appropriate altimeter to 29.92 inches of mercury.
(e)
On test set, position MODE switch to mode C, and READOUT switch to ALTITUDE. Hold POWER switch ON, readout windows should indicate field elevation as indicated by altimeter | 75 feet.
EFFECTIVITY AF ALI ALL; DLH ALL; IBE ALL;
AF SAB ALL; AF, AT,MD, GN, AF AND VM WITHOUT AEB 34-587 CONFIG 1 AF AND 34-607 02 A Page 507
Oct 25/96
34-53-00
NOTE: READOUT switch may be changed to PILOT position and
____ test set will indicate altitude transmission code for indicated altitude. READOUT selector may be placed in BINARY position and will indicate actual number of A-B-C-D pulses transmitted.
The tester will add 400,000 feet to altitude if any invalid C pulses are present (CO - C5 - C7), 200,000 feet if any invalid D pulses are present (D1 - D3 -D7), and 600,000 feet if both erroneous. C and D bits are present.
When there is no Mode C information, such as would occur with a disconnected digitizer, test set altitude readout will be 4007. This can be verified by setting readout switch to PILOT. A display of 0000 will be indicated.
(f) Using air data test set and altitude reporting code list (Fig. 501), apply a static pressure to obtain a sufficient number of test altitudes (between 0 and 35,000 ft.) to verify the following: 1) Binary code lines (A1 thru C4 and D4) between transponder
and altitude source are not open or shorted to ground.
2) Appropriate altimeter is within tolerance (AMM 34-12-00).
3) At each altitude, the difference between ATC test set
display and altimeter reading does not exceed | 125 feet.
NOTE: A test altitude above 30,800 feet is required for
____
check of D4 pulse.
The altimeter reading may be increased or decreased to see if 125 ft tolerance can be met PROVIDED the ATC test set continues to display the designated altitude.
(g) Repeat step (f) decreasing altitude to field elevation.
(5)
Test alternate ATC system as outlined in steps (3)(i) thru (4)(g) (if installed/required).
(6)
Place ATC control module function switch to OFF or STBY as appropriate.
(7)
Open ATC and altitude source circuit breakers on panel P7.
(8)
If no longer required, remove external power from airplane.
5. ATC System Test (Using Instrument Flight Research ATC-600A)
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