M7.11 Flashcards
What do most bearing on an aircraft have to stop FOD getting into them?
A) Open and Closed Bearings
B) Sealed and Shielded Bearings
C) Ball and Roller Bearings
B) Sealed and Shielded Bearings
What do sealed and shielded bearings prevent?
A) Heat buildup
B) Foreign particles from entering the bearing
C) Vibration
B) Foreign particles from entering the bearing
What is usually tested when checking a bearing?
A) Rotational checks for excessive backlash or free play
B) The color of the bearing
C) The material strength of the bearing
A) Rotational checks for excessive backlash or free play
How should free play be tested in a bearing?
A) Only in one direction
B) In both radial and axial directions
C) By visual inspection only
B) In both radial and axial directions
What must happen if a bearing shows any indication of a fault or defect?
A) It should be cleaned
B) It must be removed and replaced
C) It should be lubricated
B) It must be removed and replaced
What method is used for cleaning stubborn particles or contaminants from bearings?
A) High-pressure air
B) Ultrasonic baths
C) Manual scraping
B) Ultrasonic baths
What must cleaned bearings that are not going to be installed immediately be coated with?
A) Lubricant only
B) Rust-preventing oil or a specified coating
C) Water-based cleaner
B) Rust-preventing oil or a specified coating
What is required for bearings that have been cleaned but are not immediately installed?
A) They must be wrapped in greaseproof paper, boxed, and labelled
B) They must be thrown away
C) They must be left in the open air
A) They must be wrapped in greaseproof paper, boxed, and labelled
What can be grounds for rejecting or replacing a bearing?
A) Clean appearance
B) Any flaw or defect detected in the bearing assembly
C) Minor discoloration
B) Any flaw or defect detected in the bearing assembly
When can the bearing be inspected?
A) Only after it has been installed
B) Before cleaning the bearing
C) After cleaning the bearing
C) After cleaning the bearing
What can happen if too much grease or lubricant is applied to a bearing?
A) It will improve the bearing’s service life
B) It can overpack the bearing and cause it to run hot
C) It will prevent any dirt from entering the bearing
B) It can overpack the bearing and cause it to run hot
What can excessive lubricant inside the component cause?
A) It will improve lubrication
B) It can collect dirt and cause further deterioration
C) It will reduce the bearing’s weight
B) It can collect dirt and cause further deterioration
What is the primary purpose of a lubricant?
A) To reduce friction between moving surfaces
B) To improve the appearance of the bearing
C) To increase the weight of the bearing
A) To reduce friction between moving surfaces
What is a suitable lubricant for low rotational speeds or oscillating functions?
A) Oil
B) Grease
C) Water
B) Grease
What lubricant is more suitable for high-speed applications?
A) Oil
B) Grease
C) Wax
A) Oil
What are the effects of effective lubrication on rolling element bearings?
A) Reduces friction and abrasion, reduces heat, prolongs service life, prevents rust, and keeps foreign objects away
B) Increases heat, reduces friction, and causes wear
C) Shortens service life, increases rust, and allows foreign objects inside
A) Reduces friction and abrasion, reduces heat, prolongs service life, prevents rust, and keeps foreign objects away
What type of grease is often used in bearings for airframe applications due to low temperatures?
A) Anti-freeze grease
B) High-temperature grease
C) Water-based grease
A) Anti-freeze grease
Can shielded or sealed bearings in airframe applications be regreased?
A) Yes, they can be regreased at any time
B) No, they must be replaced if the lubricant is lost or washed out
C) Yes, they can only be regreased once
B) No, they must be replaced if the lubricant is lost or washed out
What must be done before applying grease using a grease gun to a grease nipple?
A) The nipple should be lubricated with deicing fluid
B) The nipple must be wiped clean to prevent dirt from entering
C) The nipple should be heated before use
B) The nipple must be wiped clean to prevent dirt from entering
What tool is used for packing wheel-hub bearings?
A) Grease gun
B) Grease nipple
C) Bearing packer tool
C) Bearing packer tool
Which of the following are the four basic types of lubrication used for bearings?
A) Hydrodynamic, Hydrostatic, Boundary, and Solid Film lubrication
B) Oil-based, Water-based, Grease-based, and Solid-based lubrication
C) High-speed, Low-speed, Thermal, and Fluid lubrication
A) Hydrodynamic, Hydrostatic, Boundary, and Solid Film lubrication
What is Hydrodynamic lubrication?
A) A type of lubrication where the load carrying surfaces are separated by a thin film of lubricant
B) A type of lubrication where the load carrying surfaces are separated by a thick film of lubricant
C) A lubrication method that uses solid materials to reduce friction
B) A type of lubrication where the load carrying surfaces are separated by a thick film of lubricant
What is unique about Hydrostatic lubrication compared to Hydrodynamic lubrication?
A) It requires motion of one surface relative to the other
B) It doesn’t require motion of one surface relative to the other
C) It only works at low temperatures
B) It doesn’t require motion of one surface relative to the other
What type of lubrication method uses air and oil?
A) Boundary lubrication
B) Hydrostatic lubrication
C) Hydrodynamic lubrication
B) Hydrostatic lubrication
In Hydrostatic lubrication, what is forced into the bearing area at high pressure to separate the surfaces?
A) Water
B) Air
C) Grease
B) Air
In Boundary lubrication, what is the oil film between the mating parts like?
A) Thick and sticky
B) A few molecules thick
C) Very thin and unable to stick
B) A few molecules thick
In Boundary lubrication, what is more important than the viscosity of the oil?
A) The temperature of the oil
B) The color of the oil
C) The lubricity of the oil and its ability to stick to the mating surfaces
C) The lubricity of the oil and its ability to stick to the mating surfaces
What is Solid Film lubrication made of?
A) A thick layer of liquid grease
B) Paint-like coatings of fine particles of lubricating pigments
C) Only liquid oil mixed with chemicals
B) Paint-like coatings of fine particles of lubricating pigments
How is Solid Film lubrication applied to components?
A) By spraying, dipping, or brushing
B) By heating the components
C) By injecting it under pressure
A) By spraying, dipping, or brushing
Which defect is caused by abrasive substances like sand, grit, or dust?
A) Brinelling
B) Spalling
C) Dented or damaged seals
B) Spalling
What causes True Brinelling in bearings?
A) Excessive impact and static overload
B) Over-lubrication
C) Incorrect cleaning methods
A) Excessive impact and static overload
How is True Brinelling identified in a bearing?
A) By an increase in vibration and indentations in the bearing raceway and rolling elements
B) By a change in color and texture of the lubricant
C) By irregular wear patterns on the bearing surface
A) By an increase in vibration and indentations in the bearing raceway and rolling elements
What causes False Brinelling in bearings?
A) Vibration while the bearing is in a static state
B) Excessive static overload
C) Overheating of the bearing
A) Vibration while the bearing is in a static state
How is False Brinelling identified?
A) By discolouration of the bearing raceway
B) By hollow spots resembling brinelling dents caused by wear
C) By excessive grease accumulation
B) By hollow spots resembling brinelling dents caused by wear
How does False Brinelling cause lubrication to be pushed out?
A) The vibration forces lubricant out between the rollers and raceway
B) The bearing overheats and melts the lubricant
C) The bearing swaying with vibration pushes lubricant out from between the rollers and raceway
C) The bearing swaying with vibration pushes lubricant out from between the rollers and raceway
What can cause Burnishing in bearings?
A) Insufficient lubrication
B) lubrication
C) Overloading the bearing
A) Insufficient lubrication
How is Burnishing identified in a bearing?
A) By splits and cracks in bearing rings and rolling elements
B) By discoloration with virtually no measurable wear
C) By the appearance of large dents on the bearing raceway
B) By discoloration with virtually no measurable wear
What causes Galling in bearings?
A) Metal-to-metal contact due to skidding
B) Excessive lubrication
C) Vibration while in a static state
A) Metal-to-metal contact due to skidding
How is Galling identified in a bearing?
A) By metal transfer resulting from a welding or tearing action
B) By discoloration of the bearing surface
C) By the formation of indentations on the raceway
A) By metal transfer resulting from a welding or tearing action
How is Spalling identified in a bearing?
A) By irregular pitting with cracked edges
B) By discoloration of the bearing raceway
C) By the accumulation of grease on the bearing surfaces
A) By irregular pitting with cracked edges
What causes Spalling in bearings?
A) Excessive lubrication
B) Breakdown of surfaces due to cyclic loading and metal fatigue
C) Insufficient pre-load
B) Breakdown of surfaces due to cyclic loading and metal fatigue
What causes corrosion in bearings?
A) Excessive lubrication
B) Chemical attack on bearing materials, mainly from moisture
C) Overheating of the bearing
B) Chemical attack on bearing materials, mainly from moisture
How is corrosion identified in a bearing?
A) By smooth, polished surfaces
B) By black pitting marks or reddish-brown rust areas on the rolling elements or raceways
C) By loose fitting of the rolling elements
B) By black pitting marks or reddish-brown rust areas on the rolling elements or raceways
