Altimeter; Airspeed Indicator; Magnetic Compass - Thrush Aircraft S2R–T660 Maintenance Manual

THRUSH AIRCRAFT INC - T660 TURBO THRUSH AIRCRAFT MAINTENANCE MANUAL
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.

ALTIMETER

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.

AIRSPEED INDICATOR

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.

MAGNETIC COMPASS

The magnetic compass is a semi-floating cylinder encased in a liquid filled case with expansion provisions to
compensate for temperature changes. The compass is mounted on the instrument
8 – 5
** CAUTION **
Do not apply positive pressure with the airspeed indicator
connected to the static pressure system.
Effective: 12/17/03