PNEUMATICS

CW2 WESTBROOK

Introduction

Pneumatics, from the Greek word “pneumaticus”, which is the branch of physics dealing with the mechanical properties of gases.

Agenda

Pneumatic power source Systems operated by pneumatics Diagram of the pneumatic system Inspection of the pneumatic system

Overview

Pneumatics system is designed to provide power to other systems needed for aircraft operations and not as a stand alone system

REFERENCES

TM 1-1520-237-23 TM 1-1520-237-10

PNEUMATIC POWER SOURCES

Operates from bleed air furnished from: Main Engines APU Ext pneumatic power source

SYSTEMS OPERATED BY PNEUMATICS

Main Engine starters Aircraft heater External ERFS Engine inlet anti-ice (from main engine

bleed air)

DIAGRAM OF PNEUMATIC SYSTEM

HEATER

HIOFFONON

OFF

OFF

VENTBLOWER

ONON

OFF

OFF

NO. 1 NO. 2

ENG ANTI-ICE

UH-60 PNEUMATIC SYSTEM DIAGRAMCPT MURPHY, NYARNG

Copyright 1995

AIR SOURCEHEAT / START

ENGINE

APU

OFF

#1 ENG INLETANTI-ICE ON

#2 ENG INLETANTI-ICE ON

TO ICE DETECTOR

PROBE ENGINE INLET

ANTI-ICE MODULATING

VALVE

ENGINEANTI-ICE VALVE

TO EXTENDED RANGEAUX FUEL SYSTEM(14-18 PSI)

When ENG ANTI-ICE switches are ON and ambient temperature (sensed at Ambient Sense Port) is below +4 C, degrees bleed air enters engine inlet fairing. When fairing temperature reaches +93 C, ENG INLET ANTI-ICE ON advisory light illuminates.

#1 ENGINESTARTER

#2 ENGINESTARTER

#1 ENGANTI-ICE ON

#2 ENGANTI-ICE ON

With heater ON maximum torque available is reduced by 4%, and fuel flow is increased 20 LBS per hour.

CLOSED on pre-flight , if open, bleed air can exit causing Hot Start or failed APU.

PNEUMATIC SOURCE INLET PORT

Min: 40psig and 30ppm at 149 CMax: 50psig at 249 C

Bleed air is continually supplied to the probe through holes in the left side to create a venturi effect for proper ice detection even at a hover.

Electrically closed, will open when switch is turned on (Advisory light - on) or low power setting until 88%-92% (Advisory light - off). Also below 30% in torque or due to AC power failure.

TOCABIN

AMBIENTAIR

BLOWERMOTOR

(DO NOT USE DURING HEATER

OPERATION)

HEATER

Overtemp Sensor(90 to 96 C)

when ENG ANTI-ICE is ON there will be a 16% reduction in maximum torque available for the effected engine. The fuel flow will increase 60 LBS per hour.

STARTCONTROLVALVE

CROSSBLEEDVALVE

INSPECTION OF PNEUMATIC SYSTEM

Dents up to 25% of tube diameter is acceptable

No cracks on the welds Check rubber couplings