Barometric Altimeter (AFT Cockpit)

CHAPTER ONE

T-34C INSTRUMENTS

immediately indicate a change of altitude. In addition, if an aircraft has been in a descent and

makes a transition to a climb, the altimeter will momentarily continue to indicate a descent with

the aircraft in a climbing attitude. The foregoing is one basic reason for transitioning exclusively

on the attitude gyro. A complete description of this system can be found in NATOPS.

Figure 13 Altimeter

Barometric Altimeter (AFT Cockpit)

The barometric altimeter and encoding altimeter (Figure 13) function identically as an attitude

crosscheck or performance instrument. The only difference is that the barometric altimeter lacks

the circuitry to provide altitude information to the transponder. A complete description of this

system can be found in NATOPS.

Vertical Speed Indicator

The vertical speed indicator (VSI) (Figure 14) measures the rate of change of

altitude. It is activated by the differential of static air pressures between ambient and

internal instrument air, which is permitted to equalize through a metered air flow

orifice in the instrument. This differential is indicated by the pointer on the face of

the instrument and calibrated in terms of the rate at which the altitude is changing

during a climb or descent. Refer to NATOPS for additional information.

1-6 INTRODUCTION TO BASIC INSTRUMENTS