10
Baro Calibration
Encoding altimeters provide altitude information referenced to a stan-
dard pressure of 29.92 inches of mercury. Conversion of this information
is accomplished by computers in the Air Traffic Control Centers by ap-
plying the local altimeter setting, corrected to sea level. The baro calibra-
tion mode enables the pilot to provide a current altimeter setting by con-
verting the altitude encoder output to Mean Sea Level.
When the system is initially powered up, the baro mode will be dis-
played immediately after the test cycle. At other times, it will be neces-
sary to select the DTA (Data) button for Data Entry (ENT will be dis-
played) and then select “baro” which will display the last baro setting.
Repeated pushes of the baro button will cause the displayed baro units to
alternate between displaying the setting in inches of mercury (in Hg) or
millibars. When baro is displayed in millibars, the first two digits are
omitted: 1013.2 would display as 13.2 and 1036.9 would show as 36.9.
For any questions on the setting in millibars, a quick reference to in. Hg.
can be made by simply pushing the “baro” button once again.
NOTE: To ensure optimum accuracy of the Altitude/Selector
Alerter, the barometric setting should be updated along with the
other barometric flight instruments in the aircraft, as required.
Adjustment: Baro Calibration
If the altitude encoder is in proper adjustment, simply rotate the input
selector knob to display the desired baro calibration, matching the cur-
rent altimeter setting as shown in the Kollsman window of the altimeter
to the nearest 1/10th of an inch of mercury or millibar. Rotate the selec-
tor knob clockwise (CW) to increase the setting (regardless of whether
the selector knob is pushed in or pulled out).
In normal use, it is not uncommon for encoders and/or altimeters to
vary in calibration. When this occurs, the altitude selector will engage the
altitude hold mode (ALT) on the autopilot at an altitude that is higher or
lower than that selected. These calibration variations can be compensated
for as follows:
Summary of Contents for ST360
Page 1: ...Altitude Selector Alerter P N 01279 I0 0 I6 Pilot s Operating Handbook...
Page 3: ...3 NOTES...
Page 6: ...6...
