Neethu Nair is an aviation business analyst with experience working for airlines, MROs, and OEMs globally. The document discusses the processes for hangar and line maintenance. It describes the procedures for routine maintenance prior to aircraft arrival such as creating work orders and requesting parts. Upon arrival, technicians perform checks, access diagnostic information, and record maintenance actions before releasing the aircraft. Defects can either be deferred according to MEL or CDL guidelines or immediately solved depending on the situation.

1. Neethu Nair
Aviation Business Analyst

2.  Business Analyst - Lodige Systems Middle East since 2015
 Senior Business Analyst - IBS Software Services, 2011 – 2015
 Graduate in Aeronautical Engineering, 2007-2011
 Worked for various clients - airlines, MROs and OEMs across the globe
 Experience in project implementation in different countries

3.  Hangar Maintenance – Work done on the A/C in
the hangar
 C checks and Higher
 Engine Changes
 Corrosion Control
 A/C Modifications etc.
 Line Maintenance – Work done on the A/C on
flight line while the A/C is in service.
 Turnaround maintenance & servicing
 Daily checks
 Short interval checks

4. Prior to A/C arrival
 Creates a WO for Routine Check/ Routine
Maintenance activity
 Parts are requested accordingly from company or
customer inventory
 Special Requirements for tools are requested, If
any
 Issue counter officer/ Stores officer verifies the
pick list and issue the parts for the WO
 Local Technician prints out the maintenance
tasks (Predefined by MCC for each flight from
MPD) from the computer workstation in the
maintenance office

5. Arrival At The Gate
 Routine checks are performed by the technicians
 Flight crew hands over the maintenance log book
to the technician
 Technicians access the information on the on-
board diagnostic computers which automatically
detects the faults during the flight
 Technician/ Authorized Engineer records all the
maintenance actions that were taken
 Certifies that the A/C can be returned to service

6. Sources of Defects
Routine
 Regular tasks assigned by Maintenance Control
for each aircraft
Non-Routine
 Problems discovered during routine checks
 Problems discovered by the crew during flight
 Problems/ Malfunctions of components recorded
by aircraft’s in-board diagnostic computers

7. If any defects are identified during routine
maintenance, there are two ways to address
each problem –
 Defer the Defect
 Solve the Defect

8. Why to Defer a Defect (OR) Carry Forward
Defect?
 Some defects can be deferred for specified
periods of time as this is the most desirable
option if the defect cannot be resolved
quickly
 Deferral allows the aircraft to depart on
schedule

9. Conditions to Defer a defect
o To defer a defect, the defected part should
be listed either in MEL or in CDL
MEL – Minimum Equipment List
Records the list of parts that can be inoperative for any aircraft
CDL – Configuration Deviation List
Identifies any external parts of an aircraft type which may be
missing at the commencement of a flight, and which contains,
where necessary, any information on associated operating
limitations and performance correction.
o Selection of airport within deferred limits
Maintenance control to choose an airport that has the most
appropriate technicians and facility to accomplish the maintenance
work.

10. Solving a Defect
Defects which does not fall in the below
categories must be resolved before the next
flight.
 Defects that are not deferrable according to
MEL & CDL
 Defects those are already deferred

12.  A/C Aircraft
 WO Work Order
 MEL Minimum Equipment List
 CDL Configuration Deviation List
 MCC Maintenance Control Center
 MPD Maintenance Planning Document
 FIM Fault Isolation Manual