Chapter 4 Flashcards
(36 cards)
What is required when installing a gas turbine engine in an aircraft?
A number of accessories fitting and connections to various aircraft systems are required.
How is the engine identified on multi-engine aircraft?
The left (port) engine is No 1 and the right (stbd.) is No 2.
How is the engine identified on single-engine aircraft?
The engine is always known as No 1.
What are the two ways an engine can be referred to?
- The Engine: consists of the engine without any supporting accessories.
- The Engine Change Unit (ECU): consists of the engine plus its supporting accessories.
What checks are performed for pre-installation of a replacement engine?
- Log Cards
- Modification State
- Checklist (using the aircraft parts catalogue)
- Removed ECU (may remove a starter motor/generator)
What checks are carried out before post-installation ground runs?
- Independent Inspections
- Loose Article check
- Fuel flow
- Tool control
- MoD F700 Aircraft āSā to Ground Run
How are turbo shaft engines installed into airframes?
Turbo shaft engines are installed via engine mounts and engine attachments.
What are engine mountings?
Engine mountings are used to install turbo shaft engines into airframes via engine mounts and engine attachments.
What happens during the removal of an ECU?
During the removal of an ECU, many pipes will be disconnected as will the transmission system.
Why is it essential to fit blanks to orifices during disconnection?
It is essential to fit blanks to all orifices to prevent foreign objects from entering the various systems and to prevent the ingress of dirt and moisture.
What determines the mounts employed in engine installations?
The mounts depend on the design of the installation and are generally vibration absorbing.
What can deterioration of the vibration absorbing material lead to?
It can lead to mis-alignment of the engine.
How is the engine typically mounted in helicopters?
The front of the engine is attached to the transmission, avoiding the expansion problem.
What is often employed to absorb the torque reaction between the engine and the airframe?
A thrust bar or a twin engine mount is often employed.
What does the forward mount connect to?
The engine front mounting is attached with the reduction gearbox to the air-intake-case hub.
What is the function of the gimbal ring in the forward mount?
The gimbal ring connects the engine front mounting and the aircraft main rotor gearbox support-assembly.
What does the gimbal ring include?
The gimbal ring includes four spherical bearings which are opposite each other.
What does the rear mount consist of?
The engine rear mounting includes two link plates attached to a lug on the bottom of the engine interstage case.
How is the rear mount housing attached?
The housing is attached to the decking with two bolts.
What does the rear mount permit during engine removal and installation?
It permits a small movement in a longitudinal direction.
What is Lateral Restraint?
Lateral Restraint (Side Stay) holds the engine laterally with a side stay attached between the outboard lug on the engine inter-stage case and a lug on a support attached to the engine bay deck. Each lug contains a spherical bearing.
What is the function of a Vibration Mount?
A Vibration Mount usually carries the vertical weight of the engine. As the rubber material deteriorates, it can affect the alignment of the engine, resulting in rapid deterioration of the fixed mounting spherical bearings.
Where are Lifting Points located on an engine?
Lifting Points are fitted on all engines as part of the main structure and are located at the centre of balance point.
What should be checked before lifting an engine?
Before lifting, examine the lifting points on the ECU, carry out a Pre-use check on the lifting tackle, ensure the lifting beam is of the correct type, and observe all safety procedures, including wearing hard hats and not standing under a suspended load.
