M15.19 Powerplant Installation Flashcards
What is a firewalls function?
To isolate the power plant from the airframe structure in case of fire and the heat created during normal engine operation
Examples of ‘fire zones’?
Case around compressor
Combustor
Turbine section
Firewalls are typically made from what?
Sheet metal shields such as stainless steel or other high heat resistant metal
What are cowlings used for?
Offer protection to the engine and its accessories
Streamlining
Aerodynamic surface
The cowlings are designed to do what with cooling air?
Route is effectively around the engine and its components
Thrust reverser ducts are often referred to as what?
C ducts
What are c ducts secured to?
The nacelle mounting strut by hinge pins
How do you open C ducts and how are they supported when fully opened?
Opened for maintenance using hand operated hydraulic pump or electric pump.
Once fully opened they are supported by hold open rods
What is one method of suppressing sound from the fan stage of a high bypass ratio engine?
Noise absorbent liners around the inside wall of the bypass duct
Disadvantage of using acoustic liners?
Increase weight
Increase fuel consumption caused by increasing inlet friction
C duct cowls tend to be lined with what to contain noise from fan and turbine sections?
Honeycomb acoustic liners
Due to wide temperature variations, engine mountings must be designed how?
Designed to allow for expansion in both axial and radial directions
On side mounted engines, the front and rear saddle type beams connect how to the airframe?
Front and rear saddle type beans connect through fillets to the airframe
On side mounted engines, the beams are connected to the engine mounting points by what?
Swinging links and thrust trunnions
With thrust strut connected to airframe
How do pylon mounted engines connect to the pylon?
By front and rear brackets attached to links at the top front and rear of the engine
What loads do forward engine mounts take?
Vertical
Side
Axial
Aft mounts take what loads?
Vertical
Side
The main mounting bolt/trunnion assemblies often have what type of bearings why?
Spherical bearings
Allow for expansion and torque
What are slinging points?
Provided for the attachment of dedicated equipment for engine removal
What is vital to remember about fuel line fittings?
Ensure all fittings are compatible with their mating parts. Many are interchangeable but have different thread pitch that could cause leaks
Where should wire bundles not be routed?
Areas where they could be used as handholds
Where they could be damaged during removal of aircraft equipment
High temperature equipment areas
Wiring routed across hinged panels must be routed and clamped why?
So the bundle twists and not bend when panel is removed
The minimum radii for bends in wire groups must be not less than what?
Must not be less than 10 times the outside diameter of the largest wire
Can be bent at 6 times their outside diameter at breakouts
Or 6 times the diameter where they must reverse direction
Main components of a drain system?
The drain lines which collect fluid
Module assembly where all the drain lines end
The lower part of the drain system assembly consists of what?
The drain mast which takes the fluid overboard
Typical leak points in engine?
The pylon
The oil tank scupper
The bearing sump seal drains
The fuel oil heat exchanger
Accessory gearbox
