Download Chap 1 Aircraft maintenance introduction

Aircraft Maintenance
Management Module
Aircraft Maintenance
Introduction
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General definition
 Maintenance cost is broadly defined as the sum of
incurred labour, material costs and various overheads
otherwise known as indirect maintenance costs. The
labour is normally a process time controlled and
productivity related where certain tools such as lean
processes or “Six sigma” can be employed to enhance
productivity and consequently improve consumed
labour.
 The material element is dependant on negotiated
supplier’s contracts and products reliability programs.
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1. Aircraft Maintenance Cost
Philosophies & Economics
 The maintenance costs represent 10-20% of the
worldwide airlines direct operating costs. These costs
are growing in view of introduction of new more
expensive
material,
highly
sophisticated
repair
schemes especially those associated with structural
parts and core Engine parts, and increasing labour
costs.
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 Boeing suggests that there are many other influencing
factors to the maintenance costs such as Aircraft
utilisation, Environment and Age. Furthermore,
Airlines influence costs of its operations and
maintenance support practices; similarly component
Manufactures
influence
product
support
and
reliability.
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 The Airlines overall maintenance costs are categorised
as Controllable and Non Controllable Costs. The
controllable cost element is further split into
contractual and non contractual costs. The contractual
cost elements are either outsourced or accomplished
In-house depending on potential benefits or savings in
the short or long runs.
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 Thus it is of extreme importance to understand all
elements of airlines maintenance costs and contain
such costs where practicable through introduction of
processes and manpower improvements, enhanced
training and optimisation of maintenance interval
requirement for both ON/OFF aircraft maintenance in
liaison with the OEMs.
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 The Airline industry currently under tremendous
pressure in light of the current downturn reducing
demand especially on premium cabin, hence the
competition which resulted in fares reduction and
subsequently low yields than breakeven costs.
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2. Maintenance Costs (Direct
/Indirect) Breakdown
 The Maintenance costs are the sums of total costs
pertain to Direct and Indirect Maintenance. Per IATA,
Direct Maintenance comprises the following, by Cost
segment:
 - Airframe, Engines and component maintenance. And
by cost element: Labour, Material and Outside repair
Where, Indirect Maintenance includes the Overheads
costs.
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 Boeing elaborates on these definitions further as
follows:
- Direct Maintenance Cost is, the direct airframe
and Engine maintenance which consist of the
labour and material required to perform service,
repair, modification, restoration, inspection, test,
and troubleshooting tasks during on-airplane and
shop maintenance activities.
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 Maintenance Overhead consists of maintenance
supervision, maintenance training, maintenance
planning, unallocated labour costs, rentals and
Utilities.
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 We have to understand the elements that comprise the
Direct Maintenance Cost (DMC) and Indirect
Maintenance Cost (IMC). The breakdown of these
costs is:
 2.1 Direct maintenance costs
 2.2 Indirect maintenance costs
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2.1.1
ON aircraft maintenance
 This type of maintenance is normally carried out
during the scheduled aircraft checks as defined by the
Manufacturer’s MPD documents where an extensive
part of Labour Man-hours is expended as compared to
materials consumed such as filters, oil, greases,
fittings and minor structural parts.
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 Additionally, allotted portion of check time is
dedicated to tests, inspection, minor airframe
corrections and components removals which are
due for routine maintenance. IATA as shown in
Figure (1) below refer to this maintenance
category as 1st Level Maintenance costs segments
that include Airframe and Engines Labour,
materials and subcontracted work.
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1. Maintenance Cost Breakdown
1st Level : Total Cost during period
1- Direct Maintenance Cost
Airframe
/
Engine
Component /
Overview
On Aircraft
Off Aircraft
- Labor
- Material
- Subcontracted
- Labor
- Material
- Subcontracted
- Labor
- Material
- Subcontracted
2nd Level : Cost per Maintenance Event
Labor (MH)
- routine
- non routine
- modifications
- cabin ...
Material
- P/N
- Quantity
- Cost ...
Per Remove
- MSN
- ETT
- Repair Cost ...
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Detailed listing
- P/N
- Quantity
- MTBUR
- Repair Cost ...
Maintenance Cost Task Force 2009
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Aircraft Maintenance Costs in Perspective
Life cycle cost
Total operating cost
© AIRBUS S.A.S. All rights reserved. Confidential and proprietary document.
Direct operating cost
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Disposal cost
Indirect operating cost
Financial
Passenger services
Insurance
Marketing and sales
Crew
Indirect maintenance cost
Direct maintenance cost
Other
Landing & Navigation fees
Fuel and oil
Cash operating cost
Aircraft Maintenance Costs - Guest Lecture - Cranfield University - March 2009 - CSMAM - Ref. D09005085 Issue 1
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2.1.2
OFF Aircraft
Maintenance
 This is normally carried out away from aircraft on Engines
and components in either In house or outsourced overhaul
shops as these costs comprise expended labour, material,
testing and modifications.
 The above two categories are generally split as per below
percentages.
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 The ON aircraft Maintenance checks are further summarised as
follows:
1. Aircraft Transit checks- this is a normal minor check that
occurs every flight where walk around is conducted by the
Engineers to detect any obvious damage and/or discrepancy
which my obstruct aircraft despatch or serviceability for further
flights. Also aircraft Log books will be reviewed to clear or
defer all recorded snags.
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1. Aircraft Service or Weekly checks- This check is a little
more extensive hours are expended in general visual
inspections
and
overall
Aircraft
condition.
Minor
modification (Engineering Orders) can be conducted and
additional defects clearances which require extended times
can be accomplished during this check.
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1. Aircraft “A” checks- This is a routine MPD check that
occurred almost every three months or 500 flight hours
with various tasks scheduled for accomplishment. Few
access panels, Engine cowlings and other doors will be
opened to perform certain visual inspections and
rectifications.
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1. Aircraft “C” checks- within this check the aircraft is grounded
for an extended time where many routine MPD tasks will be
carried out. As majority of access panels are opened, a detailed
visual inspection will be carried out on airframes linkages,
structural fittings and main systems (such as oil, hydraulic and
fuel) functional or leak checks and major components defect
rectification. The interior cabin such as seats will be removed
fro refurbishment. Galleys and toils will receive servicing and
repairs.
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1. Heavy Aircraft checks or “D” checks as some airlines
call it. The aircraft will undergo a detailed visual
inspection almost in every area including main structure
where a NDT and application of special die pent rants will
be carried out to detect possible skin cracks. Within the
cabin the primary structural parts removed for corrosion
treatment especially galleys, floor panels and seat main
frames.
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OFF Aircraft Maintenance
 The OFF aircraft Maintenance are further summarised
as follows:
a) Engine Repair and Overhaul Maintenance – during
aircraft operations, The Engines are the most stressed items
where every time the aircraft takes off, Engines parts rotate at
a very high speed with thrust causing certain wear to such
parts at an accelerated pace. Engine internal parts especially
turbine and combustion chambers are manufactured from
special materials in order to withstand the high temperatures
and pressure put on the engine during operations.
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 Hence, the maintenance is often significant and expensive
and that is the reason where majority of airlines outsource
engine maintenance to OEMs/MROs to alleviate the
burden off airlines from investment in development of
such highly sophisticated overhaul shops with special
required repairs.
 Normally the Engine initial shop visits expenses from
Aircraft induction to maturity is relatively less expensive
than aging Engine maintenance as main LLP parts requires
replacement then and such parts impose a high cost to the
Engine Maintenance.
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In general terms, the difference between engine and airframe
maintenance is that Engine material costs will exceed 80% of
the total maintenance while airframe maintenance will
equally share labour and material by 50/50%.
The Engine performance maintenance costs optimisation is
measured by the time it stays on wing as achieved by the
continuous OEM development causing less removals and
subsequently lower maintenance costs.
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1. Component Repairs, Modifications, and
Replacements
 This maintenance includes normal scheduled and unscheduled
components repairs to restore its serviceable condition. The
parts are often categorised into rotables, repairable and
expendables whereby a multiple number of repairs/resets is
possible to rotables parts and considered as assets for the airline.
 The maintenance costs associated with this part depend
significantly on whether these can be repaired In house or
outsourced. This decision highly depends on two factors, the
Turn around time and the Warranty aspect.
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 In other words, if the OEM TAT is reasonable, then it is quite
sensible to despatch such components for repairs outside under
warranty without spending much hassle to develop such
capability
and
waste
Engineers
energy
on
warranted
components especially during the initial five years from
Aircraft induction. There are occasions where rotables or
repairable parts are scrapped due to economic conditions BER
,i.e. Where the Repair cost exceeds the 65% threshold of the
unit cost
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In-Direct Maintenance Costs
 2.2 Indirect Maintenance Costs
 The Indirect maintenance cost or otherwise known as Overhead
cost is defined as the sum of all labour and material costs for
support services which add to the total maintenance of the
aircraft. The elements of IMC include the overhead costs of but
not limited to, Facilities, Stores, Equipment, administration,
Engineering technical services, Materials management and Engg
training.
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 The IMC costs vary significantly amongst airlines subject
together with organisational structure and the level of
In/outsourcing plus work efficiencies.
 Therefore The IMC costs fall within the category of
controllable airline maintenance costs but this factor
cannot
be
controlled
nor
quantified
by
Aircraft
manufacturers.
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 The use of automation and sophisticated control system
especially in the tech records, planning and materials
management, drastically reduce the labour requirement and
size
of
these
support
services
departments
and
subsequently slash the IMC costs.
 Therefore, the IMC costs overheads need to be reviewed
frequently to envisage possibility of introducing processes
improvements.
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 The ideal tool for this exercise would be Six Sigma which
looks at the work environment to analyse the adopted
processes, then propose solutions for the purpose of
working smarter and cut inefficiencies (Turner 2005).
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Operating Cost Breakdown
Total Operating Cost
(TOC)
Airplane Related
Operating Cost
(AROC)
Cash
Airplane Related
Operating Cost
(CAROC)
•
•
•
•
•
•
•
Fuel
Cockpit crew
Cabin crew
Maintenance
Landing
Navigation
Ground handling
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Payload Related
Operating Cost
Passenger
Related
10%
Cost
Ownership Cost
• Depreciation
• Financing (airplane and
introductory investment)
• Operating lease cost
• Hull insurance
•
•
•
•
-
Food
In flight services
Handling
Baggage
handling
• Commissions
• Reservations
and sales
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• Advertising
Cargo
25%Related
Cost
• Handling
• Commissions
• Reservations
and sales
• Advertising
System Related
Operating Cost
System
Related
Cost
• Airplane general
and administrative
• Passenger
general and
administrative
• Cargo general and
administrative
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