Technical data

13773-001
34-10
Page 1
FLIGHT ENVIRONMENTAL DATA/PITOT-STATIC SYSTEMS
1. DESCRIPTION
This section covers that portion of the system which senses environmental conditions and uses the data to
influence navigation of the airplane. This includes pitot-static, outside air temperature gage/clock, vertical
speed indicator, airspeed indicator, and altimeter.
The pitot system utilizes an “L” shaped mast with integral pitot tube and heater located on the left wing just
inboard of the wing tip to sense impact or ram air pressure. The pitot mast utilizes an electrical heating ele-
ment to prevent ice from blocking ram air. Pitot heat is controlled by a switch located in the center of the
bolster switch panel. A amber PITOT HEAT light will illuminate if the pitot heat switch is ON and the pitot
heater is not using power.
The normal static system utilizes two ports, a static source water trap, an alternate static source selector
valve, and the necessary plumbing to provide static air pressure sensing for the airspeed indicator, vertical
speed indicator, altimeter, altitude digitizer, and, if applicable, altitude transducer. The normal static ports
are located on the left and right sides of the fuselage behind the aft cabin bulkhead. The static line runs
from these ports to a tee connector mounted on the aft cabin bulkhead to a water trap located directly for-
ward of the pitot system water trap.
The alternate static source valve is located on the lower left side of the console. The valve provides an
alternate source of static air pressure from inside the cabin in the event the normal static sources are
plugged.
Note: The alternate static source is to be used when the normal system is inoperative or malfunc-
tioning. When alternate static air is used, instrument readings will vary from normal reading
due to static air being obtained from the cabin. Refer to the Pilot’s Operating Handbook for
flight operation using alternate static air.
The Outside Air Temperature/Clock, located in the upper right portion of the pilot’s instrument panel. The
OAT gage is integral to the clock. The clock provides Universal Time (UT), Local Time (LT), Flight Time
(FT) with alarm, Elapsed Time (ET), Outside Air Temperature (OAT) in °C or °F, and Voltmeter functions. All
features and functions are selectable from control buttons on the clock face. The clock receives the OAT
signal from a temperature sensor installed immediately forward of the pilots door. The clock operates on
28VDC supplied through a 5-amp fuse connected to the airplane primary bus in the Master Control Unit
(MCU). A replaceable AA battery is installed to provide up to three years battery back up. (Refer to POH)
The Vertical Speed Indicator, located in the lower right portion of the pilot’s instrument panel, measures the
rate of change in static pressure when the airplane is climbing or descending. By means of a pointer, it
indicates the rate of descent or ascent of the airplane in feet per minute. A zero adjust screw is located on
the front of the VSI in the lower left corner to allow for pointer adjustment.
The Airspeed Indicator, located in the upper left portion of the pilot’s instrument panel, is a differential air
pressure gage which measure the difference between ram air pressure and static air pressure to indicate
the speed of the airplane. An adjustment knob allows the pilot to correlate outside air temperature with
pressure altitude, thereby allowing the airspeed indicator to show both true and indicated airspeeds. A
moveable pointer and a fixed dial with the 0 index at the 12 o’clock position indicates airspeed. Range of
the instrument is 0 to 220 knots.
The Altimeter, located in the upper mid portion of the pilot’s instrument panel, converts static pressure into
a visual indication of airplane altitude above sea level. Pointers on the instrument dial indicate altitude in
increments of 100, 1000, and 10,000 feet, with a range of -1000 to 20,000 feet.
31 July 2001