1. MRO- Maintenance, Repair & Overhaul
The aircraft maintenance, repair and overhaul services will ensure optimal quality and reliability to achieve the highest quality for commercial aircraft, engines and systems.

2. MRO- Maintenance, Repair & Overhaul
Aircraft MRO is the overhaul, repair, inspection or modification of an aircraft or aircraft component
Maintenance includes the installation or removal of a component from an aircraft or aircraft subassembly, but does not include:
Elementary work, such as spark plugs, checking cylinder compression, etc

3. MRO- Maintenance, Repair & Overhaul
Servicing, such as refueling, washing windows
Any work done on an aircraft or aircraft component as part of the manufacturing process, prior to issue of a certificate of airworthiness or other certification document

4. Types of Maintenance
Each airline develops its own program, based on manufacturer’s planning documents, but includes adjustments for the airline’s own operations
Each aircrafts requires different operators and programs
BUT, aircraft of the same number of routine maintenance hours during the program cycle

5. MRO- Maintenance, Repair & Overhaul
Maintenance of aircraft usually categorized into
Product type (airframe, engine and components)
Timing and purpose of work
Then, resulted into 4 categories
Routine scheduled maintenance
Non-routine maintenance
Refurbishments
Modifications

6. Routine scheduled maintenance
Includes airframe and engine checks
The most elementary is visual inspection of the aircraft before flight- ‘walk-around’
To ensure there are no leaks, missing rivets or cracks
Types of checks-In Grades
Overnight
A-Check

7. Routine scheduled maintenance
B-check
C-check
D-Check
Overnight: Operate 1 to 1.5 hrs. inspection (End of working day) to ensure the plane operating in according to OEM ‘s (Original Equipment Manufacturer) minimum list
In, example installation of telephones and other devices

8. Routine scheduled maintenance
A-Check: Done after 125flight hours (2-3 weeks)
An amplified preflight visual inspection of plane's power plants, avionics and accessories
B-Check: Done approximately after 175 flight hours (3 to 4 months)
An open inspection for preventive maintenance (exterior wash, engine oil)
Oils filters are removed and checked, parts are lubricated and carefully examined

9. Routine scheduled maintenance
C-check: Carried out approximately for every 3000 flight hours (15 months)
Incorporates both A and B checks
Components are repaired,
Flights controls are calibrated
Major internal mechanism are tested
Other tests include minor structural inspections, compressor, flight control rigging tests, engine, compressor washes, aircraft appearance maintenance, and post-check flight tests

10. Routine scheduled maintenance
D-Check: The most intensive, approximately 20, 000 flights hours (6-8 years)
Cabin interiors (including seats, galleys, lavatories, cockpit, furnishings, headliners and sidewalls) are removed to enable careful structural inspections
Flights controls are examined and the fuel system is probed for leaks and cracks
The aircraft is stripped to its shell and rebuilt to return it to its original con

11. Non-routine Maintenance
Done due to unforeseen event such as accident.
An example of the first engine damage due to bird ingestion or an airframe dented by a catering truck
Done also for an aging aircraft

12. Refurbishments
Any form of upgrading of cleaning, brighting, or making it fresh again.
To renovate and upgrade the aircraft
For example: Cabin upgrades and exterior painting

13. Modifications
Any form of small alteration, adjustment, or limitation to fulfill the aircraft’s owner.
Most modifications are carried out within the interior design, not much on the airframe and engine.
For example: Installation of karaoke, PS3 and various kind of entertainment in the cabin

14. Overhaul of airframes
A plan where a series of seven minor overhauls and one major check were conducted on aircraft
The major overhaul was designed to rework the airplane to a like-new condition-to fit the bits and pieces back together to the exactness of current manufacturing tolerances

15. Overhaul of engines and other components
Components are brought in when either operating time/ condition requires it
The overhaul returns them to specifications laid down by engineering and manufacturer
BUT when practical, engine changes are made during maintenance checks or airframe overhauls

16. Contract Maintenance When?
When the airline do not have the personnel and equipment to perform maintenance
When serving a distant airport at which they do not have maintenance support
Why?
Different types of aircraft requires different expertise from different areas
Low labor cost
Important note:
Some contracts extend to other functions, such as cleaning and fueling the aircraft