ENVIRONMENTAL CONTROL SYSTEM

PILATUS PC-7 MKII

LT M AHMAD KHUZAIREY BIN MD NASIR TUDM

cooling system

INTRODUCTION & DESIGN PHILOSOPHY• The PC-7 MkII cooling system is a vapour

compression cycle system that uses a refrigerant to absorb the heat from the cockpit air.

Main components

• The cooling system, as installed on the PC-7 MkII, consists of:- A compressor- A condenser and blower fan- A receiver/dryer- Two evaporators- Two ECS control panels- Two maintenance valve switch assemblies- Refrigerant hoses and pipe fittings

Main components

Normal Operation Cooling Process

With the cooling system switched ON in the front cockpit (engine running), the compressor compresses the low pressure refrigerant gas and turns it into a high pressure refrigerant vapour

The compressed/vaporised refrigerant is pumped to the condenser where it is cooled and condensed into a high-pressure liquid

From the condenser the refrigerant moves to the receiver/dryer where it is dried and filtered

From the receiver dryer the refrigerant liquid flows to the evaporator expansion valves, that control the refrigerant flow rates

Blower fans circulate cockpit air through the evaporator heat exchangers which extracts the heat from the air. The heat is absorbed by the refrigerant in the evaporators and the refrigerant is again vaporised

The refrigerant returns to the compressor and the cooling cycle is repeated

Cockpit Airflow• Two torso outlets, on the centre console in

each cockpit, allows for the distribution of cooled air through the cockpit

• An air distribution control lever, on the centre console, directs air to the various outlets

Summary The Cooling System can be switched on from

the front Cockpit ECS control panel A refrigerant is cycled through various stages of

the aircraft's cooling system to produce cool air Blower fans controls the rate of flow of cooled

air Torso outlets can be adjusted to control the

volume and direction of cool air

Malfunctions and Emergency Procedures

• The cooling system in the PC-7 MkII is a vapour compression cycle system

• A refrigerant is cycled through the cooling system where it is cooled to help absorb the warm cabin air

• Cool air is delivered to the cockpit through two torso outlets in each cockpit

• In case of a cooling system failure: Land as soon as possible Climb to higher altitudes for crew comfort if landing within a reasonable time is not possible

Land as soon as possible

Climb to higher altitudes

Emergency Operations

heating system

INTRODUCTION & DESIGN PHILOSOPHY Cockpit heating in the PC-7 MkII is achieved

through a heating ram air system Heat is provided by combining outside ram

air with hot P3 compressor bleed air The heated air is delivered in the cockpit

through ducts to foot and de-fogging outlets

Section SummaryCockpit heating in the PC-7 MkII is achieved

through a heating ram air system that mixes outside ram air with hot air from the engine P3 compressor section.

Main Components

Main Components

• The heating ram air system, as installed on the PC-7 MkII, consists of:- A butterfly valve- A bleed air heater with integral flow regulator- A temperature limiting switch- A shut-off valve- A ram air temperature control knob- A system of ducts and control levers to distribute the air

Normal Operation

Heating Process• The ram air temperature control knob on the ECS

control panel (labelled OFF / RAM AIR / HEAT) controls the flow and temperature of air through the heating ram air system.

• Heating and ram air can only be selected ON / OFF from the front cockpit ECS control panel. The panel also contains the cooling system COOL and FAN toggle switches. (Airflow volume and direction can be controlled individually from both cockpits).

- Ram air is blocked by the butterfly valve when the ram air temperature control knob is in the OFF position.- Selecting RAM AIR on the ECS control panel will open the butterfly valve and allow only outside fresh ram air to enter the system through the foot and de-fogging outlets.

- Selecting the HEAT positions on the ECS control panel energises the flow regulator and allows bleed air to pass the flow regulator and mix with the ram air.

Air Distribution• An air distribution control lever is located

above the cool air torso outlets, on the centre console of each cockpit

Firewall Shut-Off T-Handle• The firewall shut-off T-handle, when pulled,

activates the heating ram air system shut-off valve and blocks the flow of air to the cockpits. (The firewall shut-off T-handle also activates the shut-off valves for the fuel and hydraulic systems)

Malfunctions and Emergency Procedures Emergency Operations

• If the temperature limiting switch malfunctions and the duct temperature reaches 120°C:- The master caution will be triggered- The OV TEMP caption on the EID will come ON

• In such a case you need to:1. Reset the master caution2. Open the ram air3. Pull the cockpit heating circuit breaker

Summary Cockpit heating in the PC-7 MkII is achieved through a heating

ram air system that mixes outside ram air with hot air from the engine P3 compressor section

The heating ram air system can be switched on from the front Cockpit ECS control panel

An air distribution control lever allows ram or heated air to be directed to the foot and de-fogging outlets as required

The firewall shut-off T-handle activates the shut-off valve of the heating ram air system, to block the flow of air to the cockpits

In case of an over temperature scenario, reset the master caution switch, open the ram air and pull the cockpit heating circuit breaker

Any Question??