Oil System

Oil System

Scope

- Brief Description

- Design and Components

- Propeller Control System

- Warnings, Cautions and Emergencies

- Summary and scores

- Discussion

Description

The oil system provides clean, filtered oil to the engine bearings, reduction gears, accessory drives and propeller control system. The oil also cools engine components and carries away impurities to an oil filter. Oil used is Exxon/BP Turbine Oil 2380 (Type II)

Multiple Choice

What design is the oil system?

• Dry Sump

• Wet Sump

• Moist Sump

Dry Sump Design

A dry sump design has a separate oil tank where oil is stored, away from the engine block. A wet sump design where oil is used and then collects in the base of the engine block before being reused.

Dry Sump Design

There are many advantages to using a dry sump including;

- The ability to increase the overall volume of oil available

- Increased oil volume has knock on effects for increased cooling and cleaning

- Allows extra Crankcase room, providing more power

Multiple Select

There are 2 heat exchanges in the Oil System. These are...

• Air Oil Heat Exchange (AOHE)

• Engine Oil Heat Exchange (EOHE)

• Hydraulic Oil Heat Exchange (HOHE)

• Fuel Oil Heat Exchange

Fuel Oil Heat Exchange (FOHE)

Used to exchange heat between the warm oil returning from the engine and the cooler fuel returning from the Header tank to the return solenoids.

Air Oil Heat Exchange (AOHE)

Oil flow through the AOHE is governed by a Temperature Control Valve (TCV). When the oil temperature is less than 85C the TCV bypasses the AOHE and routes oil directly to the oil tank. Between 85C and 90C oil flow through the AOHE is steadily increased, until at 91C all oil is routed through the AOHE.

Propeller Control System

- 2 modes of operation, ground and flight

- In ground mode oil is metered to the propeller by the pitch control unit.

- In flight mode the propeller governor meters oil to the propeller.

Multiple Choice

At what amount will the oil quantity caution appear in the HDD's?

• 70%

• 60%

• 55%

• 50%

Multiple Choice

At what amount will the oil quantity warning appear?

• 49%

• 45%

• 40%

• 30%

Oil Emergencies

Warnings and cautions include:

- Minimise manoeuvring and excessive throttle movement. This may cause propeller blade angle to be changed, resulting in a change to the amount of oil being diverted away from the engine.

- Land as soon as practical/possible.

- Oil leakages can ignite and cause a loss of the aircraft.

Engine oil emergencies can lead to engine failure if not diagnosed in time or on a lengthy transit back to the LR. Constant awareness of potential forced landing options must be maintained.

Multiple Choice

What is the normal operating temperature range?

• 56C - 119C

• 70C - 115C

• 46C - 120C

• 20C - 135C

Low Oil Temp Guidance

If oil temperature drops below the normal temps then this should be monitored. Crews should also monitor the temp trend. The Low Oil Temp checklist is required if there is a significant down trend in temps or if the temp falls below 56C. (STAN RF 19/07 20 Dec 19)

Summary

- Brief Description

- Design and Components

- Propeller Oil System

- Warnings, Cautions and Emergencies

- Scores

Discussion