Figure 1-8. Airspeed and Direction Sensor.

TM 9-1270-219-13&P

signal to the Fire Control Computer and

output

interfacing

within

the

EPU.

Outputs

from

the

and

ABS

EPU are available in serial digital and dc analog formats to

supplies analog TAS signal to the Doppler Navigation

interface with the Fire Control Computer (FCC) and the

Subsystem. An analog radar altitude signal is fed to the Air

AN/ASN-128

Doppler

Navigation

System.

Data

Subsystem

from

the

Radar

Altimeter

provide

ground effect error correction.

c. Component airspeed outputs from the EPU are

AADS

General

D e s c r i p t i o n . The AADS (fig. 1-8)

1-13.

Airspeed

Indicator

(LAI),

displayed

the

LOW

has a pitot-static pressure head which is supported on a

standard

inch

indicator

which

displays

forward

and

g i m b a l arrangement and is caused to point into the local

lateral components of airspeed up to 50 knots in any

airflow by a finned tail.

direction.

1-12.

S y s t e m T i e - i n . Connections between the Air Data

a. Both total and static pressure are sensed by the

Subsystem

and

other

helicopter

systems

are

shown

head which is always aligned with the local resultant

f i g u r e 1-7. The Air Data Subsystem supplies digital TAS,

airflow

and

therefore

does

not

suffer

from

incidence

Figure 1-8. Airspeed and Direction Sensor.

1-9