Altimeter; Airspeed Indicator; Magnetic Compass Compensation - Thrush Aircraft S2RHG-T65 TURBO THRUSH Maintenance Manual

THRUSH AIRCRAFT INC – MODEL S2RHG-T34 TURBO THRUSH
still exceeds the maximum allowable, use the following
procedure.
G. Disconnect static pressure line from airspeed indicator to altimeter. Cap tee at
altimeter so that the altimeter is the only instrument still connected to static
pressure system.
H. Repeat the leakage test to check whether the static pressure system or the
removed instruments are the cause of leakage. If instruments are at fault, they
must be repaired by an appropriately rated repair station or replaced. If the static
pressure is at fault, use the following procedure to locate the system leakage.
I. Attach a source of positive pressure to the static source opening.
Do not apply positive pressure with the airspeed indicator
connected to the static pressure system.
J. Slowly apply positive pressure until altimeter indicates a 1000-foot decrease in
altitude and maintain this altimeter indication while checking for leaks. Coat line
connections, static pressure fittings and static source external port opening with
solution of mild soap and water, watching for bubbles to locate leaks.
K. Tighten leaking connections. Repair or replace any parts found defective.
L. Reconnect airspeed indicator to the static pressure system and repeat leakage
test per steps C. through G.
The altimeter is equipped with three concentrically arranged pointers with a range of 0 -
100,000 feet. The intermediate hand indicates altitude in hundreds of feet in 20-foot
increments. The shortest hand indicates altitude in thousands of feet and the longest
pointer in tens of thousands of feet. A moveable barometric scale, visible through a
small window in the main dial, indicates the barometric pressure in inches of Hg and
millibars. An adjusting knob provides a means of adjusting the three pointers and
barometric scale simultaneously to correct for changes in atmospheric pressure and to
establish the proper reference to sea level. Barometric pressure is sensed through the
instrument static system.
The airspeed indicator registers airspeed in miles-per-hour and/or knots. The indicator
is operated by the pressure differential between impact air pressure from the pitot tube
and barometric pressure sensed through the static system.
The magnetic compass is a semi-floating cylinder encased in a liquid filled case with
expansion provisions to compensate for temperature changes.
mounted on the instrument panel, is internally lighted, and is equipped with
8-4
AIRCRAFT MAINTENANCE MANUAL
** CAUTION **

ALTIMETER

AIRSPEED INDICATOR

MAGNETIC COMPASS
The compass is
Effective: 05/05/04