TM 1-1510-262-10
NOTE
If the altimeter does not read within 70 feet of ield elevation, when the correct local barometric set-
ting is used, the altimeter needs calibration or internal failure has occurred. An error of greater than
70 feet also nulliies use of the altimeter for IFR light.
2-85. ALTIMETERS.
The pilot and copilot s altimeter tape is displayed on the PFD s on the instrument panel (Fig. 2-22 and 2-23). The
tapes move vertically, displaying aircraft altitude as provided by the air data computers (ADC). The barometric pres-
sure is set manually with the BARO SET knob, located on the Primary Flight Display Control Panel (PFDCP), and is
displayed in units of inches of mercury or HectoPiscals. Once the BARO knob is manually adjusted, the barometric
pressure is inputted to the air data computers. The ADC is supplied outside air temperature, receiving pressure
inputs from the pilot s pitot and static air sources, from which aircraft altitude above sea level is computed. The
computed altitude is simultaneously routed to the transponder (for encoded transmission to ground stations) and
the PFD s. The barometric pressure adjustment knob allows ground supplied pressure values to be adjusted and
displayed in inches Hg or HPA. See the OEM s operator manual (EFI-890R) for description and operation of these
indicators.
2-86. VERTICAL SPEED INDICATORS.
Vertical speed indicators are displayed on the PFD s on the instrument panel (Fig. 2-22 and 2-23). They indicate
the speed at which the aircraft ascends or descends based on changes in atmospheric pressure. The indicator
is controlled by data received from the ADC s. See the OEM s operator manual (EFI-890R) for description and
operation of these indicators.
2-87. FREE AIR TEMPERATURE (FAT) GAUGE.
The free air temperature gauge, mounted out board of the pilot s seat (Fig. 2-14), indicates the outside air temper-
ature in degrees Celsius (C).
Inaccurate indications on the standby magnetic compass will occur while windshield heat, radome
anti-ice, or air conditioning, are being used or the sunvisors are in the front position.
2-88. STANDBY MAGNETIC COMPASS.
The standby magnetic compass, located on the overhead control panel, is used in the event of failure of the compass
system, and for instrument cross check. Readings should be taken only during level light since errors may be
introduced by turning or acceleration. A compass correction chart, indicating deviation factors, is located on the
magnetic compass.
2-89. MISCELLANEOUS INSTRUMENTS.
a. Annunciator Panels. Three annunciator panels are installed. One is a warning panel with red fault annuncia-
tors, and the others are caution/advisory panels with amber and green annunciators. The warning panel is mounted
near the center of the instrument panel, on the glareshield (Fig. 2-10). One caution/advisory panel is located on the
center subpanel (Fig. 2-11). The mission annunciator/advisory panel is located on the copilot s sidewall. Some light
operations involve indications from the mission control panel (Fig. 4-1). Illumination of a red warning annunciator
signiies the existence of a hazardous condition requiring immediate corrective action. An amber caution annunci-
ator signiies a condition other than hazardous requiring pilot attention. A green advisory annunciator indicates a
functional situation. Table 2-6, Table 2-7, and Table 2-8 provides a list of causes for illumination of the individual
annunciators. In frontal view, the panels present rows of small opaque rectangular annunciators. Word printing on
the respective indicator identiies the monitored function, situation, or fault condition, but cannot be read until the
annunciator is illuminated. Blank annunciators (no word printing) are a non-functioning annunciator. The bulbs of
all annunciator panels are tested by activating the ANNUNCIATOR TEST switch, located on the copilot s subpanel
near the caution/advisory panel. The system is protected by the 5-ampere circuit breakers placarded ANN PWR
and ANN IND on the overhead circuit breaker panel (Fig. 2-12). The annunciator system annunciators are dimmed
when the MASTER light switch is ON and the pilot s light instrument lights are illuminated.
2-85
