56-101-01175 Revision P Page | 60
H.
Airspeed Switch Test
1. If required, from the Main Menu, select Display Setup and select
“ALT, ROC, CAS,
MACH
” display format.
2. Select Control mode.
3. Enter the Target CAS value below the operating limits of the switch.
Note
: For an airspeed switch with a 140 kts ± 2 kts trip point, start with a CAS Target
of ~136 kts.
4. If necessary, change the RtCAS Target low enough to observe the switch operation.
5. Wait for initial CAS Target to be achieved.
6. Select CAS touch zone, on Target k
eypad select “Nudge Mode.”
7. Use the Nudge Up
(↑) key to slowly increase the CAS Target value until the Airspeed
switch trip point is determined.
Note
: If required,
the Nudge value “CAS Nudge = 0.x kts” can be changed by selecting
the Define Nudge soft key.
8. Record the trip point where the switch contacts closed.
9. Use the Nudge Down key to slowly decrease the CAS Target value until the Airspeed
switch operates (opens).
10. Record the trip point where the switch contacts open.
11. On completion of the Airspeed switch testing select the Go To Ground function and
wait for the “Unit Safe at Ground” message to be displayed.
Note
: The above Nudge feature can be used with any of the Controlled Target
parameters such as ALT, ROC, MACH, RtCAS, Ps, Pt, EPR.
12. ENGINE PRESSURE RATIO (EPR) TEST
A.
Preliminary Setup
1. Connect the Static (blue) hose to the PT2 (Lo) port and the Pitot (red) hose to the PT7
(Hi) port of the EPR transmitter to be tested.
2. Set the POWER switch to On.
a) Allow initialization to complete.
B.
Test
CAUTION:
OBSERVE ALL SAFETY PRECUATIONS DETAILED IN THE AMM AND/OR
CMM.
Note:
The AMM or CMM procedure should always be recognized as the primary authority
and this manual should be recognized as a secondary aide. As such the primary
objective of this manual is to provide instruction relevant to general Test Set
operation while the AMM or CMM dictates the specific test process, sequences,
and values.
1.
Method 1:
EPR Testing using conventional aeronautical units.
The EPR Ratio can be simulated using conventional aeronautical units of measure; that
is, Altitude in feet for PT2 inlet pressure and Airspeed in knots for PT7 outlet pressure.
Use Table 9 as a reference guide for setting specific Airspeed and Altitude values as
specified by the AMM, CMM, or AP to achieve the required EPR Ratio values.