Journal of International Trade, Logistics and Law, Vol. 6, Num. 1, 2020, 126-134
126
ANALYSIS OF THE PERIODIC MAINTENANCE COSTS OF AIRCRAFT FLEET
Mehmet Fatih NUMANOĞLU
Istanbul Commerce Universtiy, Turkey
İsmail EKMEKÇİ
Istanbul Commerce Universtiy, Turkey
Received: Dec 30, 2019 Accepted: April 13, 2020 Published: June 01, 2020
Abstract:
Competition in airline management is strengthening and increasing globally. Aircraft maintenance costs have an important place in this
sense. Aircraft maintenance has a direct effect on the airline's ability to keep airplanes constantly in the air. Aircraft maintenance is done
in a timely and complete manner, the airline's profit-loss balance affects. The main purpose of aircraft maintenance is to produce safer and
more secure maintenance service. This service turns into a sales and marketing service by the airline. The purpose of this study is to
investigate the maintenance costs of commercial passenger aircraft over a period of 10 years. This study is to investigate the maintenance
costs aircraft fleet-based profitability with maintenance costs and all other costs.
Keywords:
Aircraft, maintenance, costs
1. Introduction
The airline industry is one of the most unique bussines in the world. Competition in airline management is
strengthening and increasing globally. Aircraft maintenance costs have an important place in this sense. Aircraft
maintenance has a direct effect on the airline's ability to keep airplanes constantly in the air. Aircraft maintenance is
done in a timely and complete manner, the airline's profit-loss balance affects.
The main purpose of aircraft maintenance is to produce safer and more secure maintenance service. This service
turns into a sales and marketing service by the airline. If this service is not provided in a safe and secure manner,
timely flight time decreases and aircraft stays on the ground. For this reason, maintenance has an important place for
the airline. Diversification and frequent maintenance of aircraft also maximizes flight safety.
The aim of this study is to investigate the maintenance costs of 10 years old aircraft in Turkey. It’s examined the time
of entry of the aircraft into maintenance and the characteristics of the aircraft until the first flight of the aircraft
manufacturers. In order to understand the development processes and who developed them, it was useful to
establish and examine the past-future connection.
2. Methodology
The research has been prepared with the future value method of the costs that constitute the maintenance costs over
a 10 year period. Model formulation; aircraft type, maintenance interval, maintenance type was prepared using seat
capacity and other operational constraints. It is also shown by verifying the proposed methodology using fleet
maintenance data from the X airline. Future value based methodology, X airline A320, A330 and B737, B777 aircraft
types were evaluated using case studies.
Analysis of the Periodic Maintenance Costs of Aircraft Fleet
127
3. Importance of Maintenance in Airline Operating
Maintenance is an important application to keep the equipment in working order and extend its service life. The
primary stage of maintenance process, determining which machine, part or device to be serviced, planning and
scheduling which worker/operator will be assigned for maintenance, shortening maintenance times and reducing
maintence costs. The airplane is a engine-driven aircraft that keeps the airflow in the air to the pressure difference at
the lower and upper sides of the wings. Airplanes with high-speed aircraft, carrying people and cargo, are used
extensively in civilian and military operations because they save a lot of time. The most important difference that
distinguishes airplanes from other means of transportation is that they can carry a person or a cargo from one pla ce
to another in a very short time. The world's two largest aircraft manufacturers produce the most preferred civilian
passenger and cargo aircraft. Companies with a global flight network supply aircraft from these two aircraft
manufacturers. These manufacturers are the Boeing and Airbus brand aircraft manufacturers. Boeing and Airbus
offer narrow-body and wide-bodied airplanes, and offer different types of models to companies engaged in
passenger and cargo transportation. Again, there is a serious competition between these two aircraft manufacturers in
all models. They offer different types of aircraft to their customers in many areas such as passenger capacity, less fuel
consumption, fewer breakdowns, longer range. Both manufacturers are preferred by air transport companies. Planes
are called wide-bodied and narrow-body according to their size. The wide-body airplanes are single-aisle with double
aisles and narrow-body planes. Large body airplanes can also have 4 engines. (Airbus A340, Boeing 747).
4. Aircraft Manufacturers
4.1. Airbus
Airbus Industrie, a European aircraft-manufacturing consortium, was established in 1970 to fill a market niche for
short to medium-range high-capacity jet lines. It is now one of the world's two largest commercial aircraft
manufacturers and competes directly with the American Boeing Company. The jetliner market is often dominated by
orders, deliveries or annual revenues. Among the full members, the European Aviation Defense and Space Company
(EADS) with German-French-Spanish capital with a share of 80 percent and the UK's UAE Systems with 20
percent. Its headquarters are located in Toulouse, France.
Airbus Industrie employs more than 50,000 people. Employees work directly on Airbus aircraft in France, Germany,
Spain, the United Kingdom and China, and others are employed in engineering, sales, training and other professions
worldwide. The consortium has more than 1,500 suppliers and has cooperative agreements with many companies in
many countries. American companies are responsible for about a third of the components of Airbus. Common
companies perform most of their sub-factories in their own factories; For example, wings for all Airbus aircraft are
made in the UK and tail subgroups are made in Spain. Sub-assemblies are transported to the final assembly lines in
France, Germany and China by road, rail, barge, ships and airplanes (private jet fleet, Airbus Super Carrier Beluga).
Airbus A320, A330 / A340, A380 and A350 planes are completed in a complex near Toulouse, while A318, A319
and A321 planes are assembled in Hamburg.
4.2 Boeing
Boeing Company, American aerospace company—the world’s largest—that is the foremost manufacturer of
commercial jet transports.It is also a leading producer of military aircraft, helicopters, space vehicles, and missiles, a
standing significantly enhanced with the company’s acquisition of the aerospace and defense units of Rockwell
International Corporation in 1996 and its merger with McDonnell Douglas Corporation in 1997. Formerly Boeing
Airplane Company, the firm assumed its current name in 1961 to reflect its expansion into fields beyond aircraft
manufacture. Headquarters were in Seattle until 2001, when Boeing relocated to Chicago.
The Company's founding business units are organized around three main products and service groups, namely
commercial airplanes, military aircraft and missiles, and space and communications. Boeing manufactures seven
separate family of commercial airplanes brought together in two facilities (Renton and Everett), a facility in
Washington and California. The Renton factory produced the narrow-bodied Boeing 737 and made 757 aircraft
before. Wide-bodied Boeing 767 and 777 aircraft, and a limited number of 747 (largely unexpressed) were assembled
at Everett's facilities. The 787 aircraft was assembled at the Everett plant and at a plant in North Carolina, South
Carolina. Boeing and General Electric's joint venture, Boeing Business Jets, produces 747, 777 and 787 aircraft in
addition to VIP versions, as well as 737-700 aircraft based on the production and marketing of business jets.
Mehmet Fatih NUMANOĞLU &İsmail EKMEKÇİ
128
Boeing's history began in 1916, when American timber merchant William E. Boeing began building the Aero
Products Company shortly after US Navy official Conrad Westervelt developed a single-engine seaplane, B & W. . In
1917, the company was renamed Boaming Airplane Company, built araç flying boats tor for the Navy during World
War I, and successfully sold its instructors, track planes, observation vehicles, torpedo planes and patrol bombers in
the 1920s and 30s.
5. MRO Companies Performing Aircraft Maintenance in Turkey
5.1. myTECHNIC
MyTECHNIC is the world's first lean maintenance center built from the ground up. Its advantageous position
between Europe and Asia makes myTECHNIC the ideal partner for airlines in Europe, as well as for European,
Russian, Middle Eastern and African airlines. myTECHNIC was established in 2008 and in November 2010, Hainan
Group Co. Limited (HNA). HNA Group is one of the leading companies in China with its operations in the modern
service industry and has great investments in air transportation, logistics and modern financial services. HNA,
headquartered in Haikou, China, has total assets exceeding $ 30 billion by the end of 2010. Designed according to
the principles of simple management, myTECHNIC offers a wide range of services ranging from large and narrow-
bodied aircraft to engine revisions and airplanes. Since its establishment in 2008, myTECHNIC incorporates the
principles of Lean Management and productivity and safety. eliminates space, movement and time losses. It strives to
expand the areas of corporate responsibility for the environment, increase the satisfaction of its partners and reduce
the time of completion of the works. myTECHNIC hangar is located on an area of 60,000 square meters, with a 3-
storey building with 15,400 square meters of hangar space. The facility includes 24,800 square meters workshop,
office and warehouse area. In addition, there are 6,000 square meters of engine workshop. myTECHNIC received
EASA (Part 145) authorization in August 2008. SHY / JAR 145 / EASA certificates were issued by the General
Directorate of Civil Aviation (SHGM) simultaneously. In addition to these authorizations, myTECHNIC has ISO
9001, ISO 14001 and OHSAS 18001 certificates. Finally, it was authorized by SHGM as SHY / JAR-147
maintenance training organization.
5.2 Onur Air Technical
Onur Air, which has its own maintenance hangar in Istanbul Atatürk Airport since 2011, is the only private airline
with this technical capacity. Onur Air, an EASA and Bermuda Part-145 organization, will be happy to assist its,
Customer Atatürk planes during its Base and Line Maintenance services with its unique, limited slots available at
Istanbul Ataturk Airport and Antalya International Airport and at competitive prices. In addition to base and line
maintenance services, Onur Air is also authorized to issue III Level Non Destructive Testing Service for all A320
Family aircraft parts under D1 authorization and / or EASA Approved Composite Repairs. Onur Airlines
Transportation Inc. was established on April 14, 1992 and the first flight was carried out on 14 May 1992 by the A-
320 type aircraft to the Turkish Republic of Northern Cyprus Ercan Airport. In the following period, in July 1992,
he included his second aircraft, his third aircraft in December 1992 and his fourth aircraft in April 1993 in his fleet.
Onur Air, which continues to grow steadily, increased the number of aircraft in its fleet to 14 in 2002 and in the
following years respectively; 20, 24 and 28. In 2006, the number of aircraft in the fleet of Onur Air, which reached to
7,012 seats with 31 aircraft, was 29 in 2007 and 25 in 2008. Today, Onur Air serves with its fleet of 26 aircraft.
5.3 THY Technical Inc.
5.3.1 Aircraft Maintenance
Turkish Airlines Technical Inc. Since its inception, it has been providing its customers with fast and reliable aircraft
maintenance services. 9 hangars in two continents, 576.000 m2 closed area, modern facilities, international
maintenance certificates (EASA, FAA), state-of-the-art equipment and more than 7.500, all of the capable aircrafts
A, B , C and D maintenance in house. In addition to the main maintenance services provided to its customers, it
provides quality and reliable services in many fields such as cabin renovation, airplane paint, line maintenance and
business jet maintenance. Careful work carried out by expert engineers and technical staff in the field, taking care of
the wishes and needs of its customers. Turkish Airlines, especially; It provides maintenance, repair and technical
support to more than 100 domestic and foreign airlines. Was established on 23 May 2006 with 100% Turkish
Analysis of the Periodic Maintenance Costs of Aircraft Fleet
129
Airlines capital. With more than 7,500 employees and affiliates, activities in order to provide all kinds of technical
and infrastructure support related to maintenance, repair and airline industry.
6. Aircraft Types and Maintenance Intervals
In aviation industry, aircraft are aged by daily utilization with respct to 4 different usage parameters, calender day
(DY), flight hours (FH) and flight cycles (FC). FH refers to the elapsed time between wheel lift off and touch down
and a FC is defined by a complete take-off and landing sequence. For example, the maintenance planning document
of the AIRBUS A320 family defines that an A check interval corresponds to 750 FH or 120 DY, C check interval
7500 FH or 730 DY, S check interval 2190 DY (table1)
Table 1
6.1. Aircraft interval and Maintenance Costs
The below table shows the maintenance intervals for aircraft types. There are different maintenance and intervals for
each type of aircraft. which maintenance interval of the aircraft comes first, maintenance is done accordingly. C and
S treatments are also called heavy care. heavy maintenance costs are much more expensive and take longer than
others.
Table 2
Aircraft Types Maintenance Type Interval Cost ($)
A320 A
700 FH 120
DAY* 28000
A320 S 6 YE 700000
A320 C 7500 FH 450000
A330 B 42 MO 500000
A330 C
10000 FH 24
MO* 700000
A330 S 6 YE 1,500000
A330 A 800 64000
B737 A 1000 FH 30000
B737 C
7500 FH 730
DAY 600000
B777 A
1500 FH 120
DAY 120000
B777 B 730 500000
B777 C 1125 DY 750000
Aircraft Types A B C S
A320
750 FH
120 DY*
-
7500 FH
24 MO*
6 YE
A330 (Wide Body) 800 FH 42 MO
10000 FH
24 MO*
6 YE
B737 1000 FH -
7500 FH
730 DY*
-
B777 (Wide Body)
1500 FH
120 DY
730 DY 1125 DY -
Mehmet Fatih NUMANOĞLU &İsmail EKMEKÇİ
130
6.2. The average of the A, B, C and S maintenance of A320, B737, A330, B777
In this table, the average maintenance of aircraft types in one year is given.
Table 3
A B
C S
Aircraft
Count
A320 11,68 -
1,1 0,16
88
B737 8,76 -
1,1 -
66
A330 10,95 0,28
0,87 0,16
104
B777 5,84 0,5
0,32 -
38
An aircraft is maintained as per the manufacture’s guidelines approved by the aviatoin regulators. The new modern
airplane are more complex in systems which require not just mechanical skills, but also sound knowledge in systems,
functionality and maintenance procedures.
A check: During an A check all technical systems that are needed for aircraft operation are checked.
B check: Inspecting sysetems check, cracks, inspection for corrosion, structural defects. Happens for A330 aircraft
42 month, and for B777 730 day.
C, S check: C check is a major aircraft check, the aircraft structure is inspected and all systems are tested.
Periodic maintenance actions are organized in four different classes of checks. Each check is performed at a different
interval and gets more complex with the size of the interval. The given intervals can vary depending on the aircraft
type and aircraft operation.
The main purpose of maintenence;
• Protect safety and reliability of the equipments.
• In case of corruption of safety and reliability restore to factory settings.
• When the reliability level of corruption provide the necessary information for the development.
• To ensure all this with minimum total cost.
• Keep aircraft in service.
7. The calculating of maintenance and operation costs
The factors that create costs in aircraft maintenance are multiple. maintenance consists of various costs. we will
examine the maintenance costs over a period of 10 years. changing costs each year will also increase maintenance
costs.
Table 4
AC Type Sum of Total Hours Capacity Passenger Flight Time Adding Value Rate*
Operating
Income
A320 4229046253
Ticket Sales
Revenue$
2008 28786711 190 5469475090 14% 677.438.457
2009 64771907 190 12306662330 23% 1.068.609.000
Analysis of the Periodic Maintenance Costs of Aircraft Fleet
131
2010 112592604 190 21392594760 30% 1.697.210.616
2011 160891427 190 30569371130 33% 2.315.310.776
2012 223412645 190 42448402550 34% 2.783.586.415
2013 332497086 190 63174446340 36% 3.590.374.921
2014 463890783 190 88139248770 36% 4.022.031.807
2015 560843117 190 106560192230 32% 3.334.791.338,
2016 661040602 190 125597714380 31% 3.063.597.362
2017 753126080 190 143093955200 31% 3.366.422.603
2018 867193291 190 164766725290 29% 3.730.351.639
A330 2003243706 - - - -
2008 18233508 290 5287717320 14% 654.926.297
2009 26748316 290 7757011640 15% 673.554.878
2010 33706555 290 9774900950 14% 775.505.068
2011 48574995 290 14086748550 15% 1.066.924.163
2012 72317976 290 20972213040 17% 1.375.268.886
2013 105288171 290 30533569590 18% 1.735.305.473
2014 182158237 290 52825888730 22% 2.410.587.878
2015 275183114 290 79803103060 24% 2.497.430.713
2016 343336365 290 99567545850 25% 2.428.665.779
2017 374849966 290 108706490140 23% 2.557.424.490
2018 522846503 290 151625485870 26% 3.432.831.348
AC Type Sum of Total Hours Capacity Passenger Flight Time Adding Value Rate*
Operating
Income
B737 5768926753
Ticket Sales
Revenue$
2008 183199379 150 27479906850 72% 3.403.607.369
2009 215414912 150 32312236800 62% 2.805.727.998
2010 263842167 150 39576325050 56% 3.139.841.604
2011 306086135 150 45912920250 49% 3.477.424.464
2012 343636893 150 51545533950 41% 3.380.137.755
2013 406543392 150 60981508800 35% 3.465.744.340
2014 491509975 150 73726496250 30% 3.364.339.010
2015 751834040 150 112775106000 33% 3.529.286.489
2016 817669097 150 122650364550 31% 2.991.705.185
2017 909992149 150 136498822350 29% 3.211.265.775
2018 1079198614 150 161879792100 28% 3.664.990.894
B777 876490394
- - -
2010 42964 370 15896680 0% 2.333.887
2011 7687982 370 2844553340 5% 384.251.313
2012 28705388 370 10620993560 15% 1.236.139.812
Mehmet Fatih NUMANOĞLU &İsmail EKMEKÇİ
132
2013 51563879 370 19078635230 20% 2.016.999.480
2014 73731536 370 27280668320 22% 2.398.565.799
2015 104413562 370 38633017940 22% 2.350.092.744
2016 140677398 370 52050637260 22% 2.098.094.805
2017 203359160 370 75242889200 22% 2.429.288.801
2018 266308525 370 98534154250 25% 3.217.971.402
*Adding Value Rate: Total hours the aircraft flies. (passenger flight time / grand total hour of seat)
*Capacity: The seat capacity of aircraft.
* Sum of Total Hours: Total hours the aircraft flies during that year.
*Passenger Flight Time: total hours the seat flies during that year.
In the below Table 5, non-maintenance sales expenses and maintenance costs are calculated. The fluctuations in
exchange rates are also taken into consideration in 2018. Net flow is the difference between ticket sales revenue and
non maintenance sales expenses. The value of the future value was also calculated by multiplying the yearly value of
the exchange rate (Table 6) with the present value of netflow. Passenger flight time was calculated by multiplying seat
capacity by flight time. From 2008 to 2018, all maintenance of aircraft was determined and cost calculation was made
according to the type of maintenance. When calculating the cost, the seat capacity of the aircraft types was found and
the seat flight time of the seats of each aircraft type was calculated. In the table 5, non-maintenance sales expenses
and maintenance costs are calculated. The fluctuations in exchange rates are also taken into consideration in 2018.
Table 5
Table 6 shows the average exchange rates on a year-by-year basis based on central bank data and is reflected in the
table as future value. thus, costs will appear to be equivalent to the present value over a period of 10 years.
Table 6
Year 2008 2009 2010 2011 2012 2013 2014 12015 2016 2017 2018
Exchange rate $ 1,29 1,55 1,5 1,67 1,79 1,9 2,19 2,72 3,02 3,65 4,81
In this below table 7, after calculating the total flight time of the fleet types over the capacity of the seats, it shows
how much a seat of an aircraft type flies in the air.
Years
Non-
Maintenance
Sales Expenses$
Maintenance Costs$
Total $ Net Flow$
Future Value
(2018) $
2008 488.651.553 2.606.837 486.044.716 188.786.904 244.084.017
2009 722.059.120 3.388.093 718.671.026 346.549.879 536.135.079
2010 1.232.946.584 3.285.069 1.229.661.514 64.264.032 696.565.040
2011 1.842.488.807 3.383.473 1.839.105.334 472.821.968 789.612.686
2012 2.169.063.429 6.404.498 2.162.658.930 614.522.986 1.101.530.752
2013 3.265.551.576 9.881.614 3.255.669.962 324.823.344 617.589.483
2014 3.808.198.637 9.560.034 3.798.638.602 213.833.169 467.836.646
2015 2.919.334.237 4.910.264 2.914.423.972 415.457.101 1.130.050.048
2016 2.523.090.959 6.329.840 2.516.761.118 540.506.403 1.633.002.278
2017 2.933.041.921 7.407.438 2.925.634.482 433.380.682 1.580.836.033
2018 2.691.007.170 4.875.129 2.686.132.040 1.039.344.468 5.002.364.929
Analysis of the Periodic Maintenance Costs of Aircraft Fleet
133
Table 7
Seat Capacity 190 290 150 370
Year A320FAM A330 B737 B777
Grand Total AC
Hour
Grand Total Seat
Hour
2008 28786711 18233508 183199379 - 230219598 38237099260
2009 64771907 26748316 215414912 - 306935135 52375910770
2010 112592604 33706555 263842167 42964 410184290 70759717440
2011 160891427 48574995 306086135 7687982 523240539 93413593270
2012 223412645 72317976 343636893 28705388 668072902 125587143100
2013 332497086 105288171 406543392 51563879 895892528 173768159960
2014 463890783 182158237 491509975 73731536 1211290531 241972302070
2015 560843117 275183114 751834040 104413562 1692273833 337771419230
2016 661040602 343336365 817669097 140677398 1962723462 399866262040
2017 753126080 374849966 909992149 203359160 2241327355 463542156890
2018 867193291 522846503 1079198614 266308525 2735546933 576806157510
8. Conclusion
In this paper presents a practical future value methodology of the maintence cost of aircraft fleet. The model
formulation takes aircraft type, status, maintenance, seat capacity, and other operational constraints into
consideration. We also validate and demonstrate the proposed methodogy using fleet maintenance data from an
airline. The proposed future value based methodology is evaluated using the case-study of an A320, A330 and B737,
777 family fleet from an airline. In this study, maintenance costs, operational expenses and all other expenses were
calculated for 4 different aircraft types. In addition, the study shows which aircraft type would be more profitable for
the airline, taking all criteria into consideration. Also, narrow body and wide body will allow the airline to choose the
type of aircraft that is profitable. We calculated below table 8, the cost per flight hour (FH) of a 10 year fleet based
on the values, we also found the cost of a fleet seat. According to this table the operator can find out which fleet is
profitable.
Table 8
Ac Type
AC Purchasing
Cost Maint Cost AC's total FH
Grand Total AC
Hour TC1 TC2
A320 $101.000.000 $827.559.933 4229046253,00 803518788070 $0,220 0,00116
B737 $106.000.000 $561.363.015 5768926753 580940674740 $0,116 0,00115
A330
(wide body) $265.000.000 $976.758.198 2003243706 865339012950 $0,620 0,00143
B777
(wide body) $375.000.000 $331.947.962 876490394 324301445780 $0,807 0,00218
TC1: aircraft purchasing cost + maintenance cost / total FH’s of aircraft
TC2: aircraft purchasing cost + maintenance cost / total FH’s of aircraft
Mehmet Fatih NUMANOĞLU &İsmail EKMEKÇİ
134
References
Airbus, (2018), A320 Maintenance Planning Document (private document)
Bazargan M, Hartman J., Journal of Air Transport Management, (2012), Elsevier.
Zorbaci B., Baynal Kasim, Uçak Bakım Planlamada Meydana Gelen Problemler ve Çözüm Önerileri
Boeing, (2012) Airplane Maintenance Program Development, Commercial Aviation Services, USA.
Boeing, (2009), Airline Maintenance Program Development Seminar, USA.
Boeing, (2018), B737, B777 Maintenance Planning Document (private document)
Central Bank of the Republic of Turkey, “Real Effective Exchange Rate“, available at:
https://www.tcmb.gov.tr/wps/wcm/connect/TR/TCMB+TR/Main+Menu/Istatistikler/Doviz+Kurlari/Reel
+Efektif+Doviz+Kuruu/
Gerdes M., Scholz D., Galar D., (2016) Effects of Condition-based Maintenance on Costs Caused by Unscheduled
Maintenance of Aircraft
Hu C-Ing, Li H. , Lui S. M., Chao C.C, (2010) Aircraft Replacement scheduling: A dynamic programming approach,
Taiwan: Department of Transportation Technology and Management, National Chiao Tung University, Hsinchu
300.
History of airbus industrie, (2018) available at: https://www.britannica.com/topic/Airbus-Industrie
History of boeing industrie, (2018) available at: https://www.britannica.com/topic/Boeing-Company
https://www.mytechnic.aero/hakkimizda
McAllister, E.W., (2015). Pipeline Rules and Thumb, Gulf Proffessional Publishing, 806p, USA.
Onur Air Airlines, (2018), “about“ available at: http://www.onurair.com/tr/kurumsal/detay/Hakkimizda/3/1/0
Directorate General of Civil Aviation of Turkey, 2019. Havacılık Personeli. //web.shgm.gov.tr/tr/havacilik-
personeli/2125-hava-araci-teknisyeni
Turkish Airlines, (2018), “Investor Relation“, available at: https://investor.turkishairlines.com/tr/maliveriler/filo