As part of our visit, aerial photography activities were carried out on the first day, and our internationally renowned Aerial Photographer (Spotter) colleague, Cem DOĞUT, had the opportunity to capture striking shots with his A400M Aircraft during the flight, which lasted approximately 1 hour, accompanied by the breathtaking Mount Erciyes in the skies of Kayseri. On the second day of our visit, we toured the Headquarters of the 2nd Air Maintenance Factory Directorate (HBFM), located in the Melikgazi district of Kayseri, in the morning. During this visit, we conducted an interview with the Technical Management Director of the 2nd HBFM. In the afternoon, we visited the Aircraft Depot-Level Maintenance and Repair Directorate, located within the 12th Air Transport Main Base Command campus, located right next to Erkilet Airport, and we took a short facility tour, getting information about the A400M C-Check Overhaul operations, and the Retrofit Project, which is currently in progress at the A400M Depot-Level Aircraft Maintenance Center, which was put into service with the ceremony held on July 8, 2021.

Brief History, Main Tasks, and Manufacturing Technologies

One of the industrial steps taken for the development of the country in the first years of the Republic was the establishment of an aircraft factory in Kayseri. On the foundations laid on an empty land, hangars were built with materials transported by mules from Mersin Port by sea and by land, and the factory was built with the labor hidden in every stone. Turkey's first aircraft factory (Kayseri) was established as the first Aircraft Factory of Turkey by the 'Airplane and Engine Turkish Joint Stock Company (TOMTAS),' which was jointly established by the 2nd Air Maintenance Factory Directorate (HBFM), the Turkish Airplane Society, and the German Junkers Aircraft Factory under the agreement signed on August 15, 1925, and the official opening of the factory was held with a state ceremony on October 6, 1926. In the year of establishment, 5 engineers, 120 German and 240 Turkish workers started working at the facility. However, as a result of a dispute between the company and the government over wages, the company's operations were terminated, and the factory was closed on May 3, 1928.

In 1930, the company's account was liquidated, and the facility was transferred to the 'Ministry of National Defence,' as it was known at that time. After 1933, with the various agreements made with the USA, Germany, Poland, and England, and the great efforts of Turkish engineers and workers, the production of Curtiss Hawk, Curtiss Fledgling, Gotha Go-145, Peletel PZL-24A, and PZL-24C (a total of 24 units were produced), and Miles Magister Aircraft (24 units were manufactured until 1947) began under license. With the collaborations established at that time, the production of "Fight Aircraft" started. German Junkers aircraft and Curtiss Hawk are the best examples of these collaborations. In approximately 10 years, license agreements were made with companies in Germany, the USA, England, and Poland, and a total of 134 aircraft of 5 different types and 50 gliders were manufactured. In addition, 24 types of aircraft Depot-Level Maintenance and Modification and 14 types of engine overhauls were carried out between 1937 and 1947. 

Starting from 1950, the name of the facility was changed to 'Air Supply Maintenance and Maintenance Centre,' and in 1970, it was included in the 'Reorganization and Modernization (REMO)' Project and became 'Air Supply and Maintenance Centre.' On July 1, 1975, its name changed to 'Supply Maintenance Center Command', and as of February 19, 1986, the name of the facility became '2nd Air Supply Maintenance Center Command'.

The General Directorate of Military Factories (AFGM) was established within the Ministry of National Defence (MSB) in 2016 in order to ensure the effective management of the Military Factories within the Turkish Armed Forces (TSK) by combining them under a single financial and administrative authority, and the 2nd HİBM, which was one of the 3 Air Supply, and Maintenance Centers that were previously affiliated with the Turkish Air Force, was affiliated with the AFGM with the organizational change in 2017 and started to continue its activities under the name of the 2nd Air Maintenance Factory Directorate.

The duty of the 2nd HBFM is to ensure the safe, effective, and economical use of the weapon systems and vehicles assigned to it in order to maintain and improve the operational readiness level of the Air Forces Command and to carry out or have Depot-Level Maintenance, production, and manufacturing carried out by adhering to the principles of Total Quality Management, and the most optimum use of resources, to fulfill the Technical Management Responsibility, and to carry out supply activities covering material storage/distribution. The 2nd Air Maintenance Factory Directorate (HBFM), within this scope, meets all Depot-Level Maintenance (DLM) requirements for aircraft in the Turkish Air Force Command (TurAF) inventory, including T-41D, SF-260D, CN-235, C-130B/E, C-160D, KC-135R, and A400M aircraft. Additionally, it provides D-Level Maintenance services for ground systems in the TurAF inventory, such as aircraft arresting systems, aircraft starters, generators, and fuel tankers. The Directorate also performs maintenance, repair, and overhaul activities for Lycoming and Continental piston aircraft engines used in T-41D and SF-260D aircraft. Production capabilities include aircraft trailers, bomb-loading devices, parachutes, and auxiliary mission equipment. There are approximately 6,000 items of material products in the Unit Repair Catalog, such as propellers, landing gear, piston engines, generators, pumps, and avionics systems in the Unit Repair Catalogue of 2nd HBFM which has unit repair capabilities for T-41D, SF-260D, CN-235, C-130B/E, C-160D, KC-135R, and A400M Aircraft, as well as F-4E 2020, and F-16C/D Aircraft.

It is possible to collect the manufacturing technologies for the operation and maintenance activities of the weapon systems under the responsibility of the 2nd HBFM and the needs of the Air Force Command under 6 main headings. These technologies are: 

Machining Technologies (Lathe-Milling-Grinding) 

Sheet Metal Works Assembly Technologies (Cutting-Bending-Pressing-Assembly-Pipe/Hose) 

Hot Work Technologies (Welding-Heat Treatment-Casting-Forging) 

Surface Preparation Technologies (Coating-Painting-Sandblasting) 

Composite Technologies (Rubber-Thermo Plastic-Ballistic-Vacuum) 

Textile Technologies (Parachute - Polyester Based Fabrics, the only parachute production center for the Ministry of National Defence). 

In these technology groups, approximately 400,000 units of approximately 4,000 different items are produced annually. The number of material items in the Directorate's Material Manufacturing Catalogue exceeded 18,000.

Maintenance Concept in Military Aviation

The triple maintenance concept in military aviation is the most common method preferred worldwide. For aircraft in the Turkish Armed Forces inventory, a triple maintenance concept called Organizational Level (O-Level/A-Check), Intermediate Level (I-Level/B-Check), and Depot Level (D-Level/C-Check) is implemented. For example, according to Airbus Defence & Space (ADS) data, the A400M Aircraft must undergo O-Level (A-Check) maintenance every 150 days or 500 hours of flight, I-Level (B-Check) every 24 months, and D-Level (C-Check) maintenance every 72 months.

2nd HBFM Aircraft FASBAT (DLM) Directorate

The official opening of the new 2-bay A400M Depot-Level Aircraft Maintenance Center, which was built in a very short time by the main contractor ASFAT for A400M Aircraft (with two separate halls that are identical to each other), was held on July 8, 2021, which has active hangar, and maintenance workshops of the 2nd HBFM Aircraft FASBAT (DLM) Directorate, which can perform special maintenance that very few countries in the world can perform.

During our visit, two separate KC-135R Stratotanker Tanker Aircraft, one of which is 57-2609, which is the 2nd aircraft to undergo Pacer CRAG Block 45.1 Modernization in the USA, and the C-130B/E Hercules Medium Transport Aircraft, and CN235 Light Transport Aircraft were undergoing DLM process.

Within the scope of the KC-135R Depot-Level Maintenance process, firstly, hot reconnaissance checks are carried out to understand the condition of the aircraft at the entrance. Then, the aircraft is taken to FASBAT/DLM Hangar, large control elements of the horizontal and vertical tail are removed, and preparations are made before washing. Following this, a general washing of the aircraft is carried out, and the paint is completely removed. After the paint is removed, detailed checks of the aircraft, called cold reconnaissance operations, are carried out in accordance with the relevant work cards. Defects detected as a result of these checks are being corrected. Maintenance and repair operations are also carried out in parallel with the disruptions. After maintenance, and repair operations are carried out, and all detected problems are resolved, the assembly process of the aircraft begins. First, in-hangar function checks are performed on the assembled aircraft, and if no problems are encountered, the aircraft is sent to the paint hangar to be painted. After the painting and marking processes are completed, engine start-up and flight line function checks are carried out, and the maintenance of the aircraft is completed. The flight crew sent by the Turkish Air Force carries out a test flight with the aircraft whose DLM has been completed, and if no problems are encountered, the aircraft is handed over to the relevant unit. 

In the 2nd HBFM, which has had the Depot-Level Maintenance (DLM) capability for C-130 Aircraft since 1968, C-130B/E Hercules Aircraft is subjected to DLM every 5 years. During our visit, C-130B/E Hercules aircraft were undergoing both Depot-Level Maintenance (DLM) and processes related to the ERCİYES Project in the FASBAT/DLM Hangar. As part of the ERCİYES Project (Avionics Modernization of C-130B/E Aircraft), a total of 11 aircraft, including 2 prototypes, had been delivered as of December 29, 2023. Under the ERCİYES Project, the aircraft are delivered with significant upgrades. They are modernized with Multi-Function Displays (MFDs) and Control Display Units (CDUs) to meet international navigation requirements (GATM, RVSM, CAT-II) and equipped with two high-performance mission computers and a ground mission planning system to enhance operational efficiency. The upgrades also include night vision-compatible displays and lighting systems, along with the integration of the Link-16 Tactical Data Link capability.

The 2nd HBFM Aircraft FASBAT Directorate, which has carried out Depot-Level Maintenance (DLM) more than 120 times for the aircraft in the inventory of Turkey, which has the largest CN235-100M fleet in the world, currently carries out the DLM operations required for its aircraft every 6 years within an average of 60 business days. The 2nd Air Maintenance Factory Directorate (HBFM) also serves as the Technical Management Authority for the CN235 aircraft in the inventories of the Turkish Land Forces Command (TLFC), Naval Forces Command (TNFC), and Air Force Command (TurAF). During our visit, the CN235, T-41D, and SF-260D Maintenance, Repair, and Modernization Hangar housed two CN235 aircraft undergoing Depot-Level Maintenance (DLM) and three SF-260D training aircraft.

SF-260Ds will soon be retired by the Turkish Air Force, replacing them with Super Mushshak Training Aircraft. The Avionics Modernization Project was initiated by the 2nd HBFM to increase the flight safety required by CN-235 Aircraft and to gain capabilities such as TCAS, IFF Mode 5S, ADSB-OUT, GPS Based Navigation as dictated by international air traffic rules. The prototype (Guide Aircraft) application has been completed, and test flights have been completed. 

According to the information we gathered, the indigenous and cost-effective solution developed by the 2nd Air Maintenance Factory Directorate (HBFM) as part of the CN235 Avionics Modernization Project has been deemed highly successful by Airbus Defence & Space. The frequent landing gear malfunctions in these aircraft are also addressed domestically through the landing gear maintenance and repair infrastructure at the Aircraft FASBAT Directorate of the 2nd HBFM. In addition to landing gear, the facility also has capabilities for the maintenance and repair of propellers and Line-Replaceable Units (LRUs).

C-Check Overhaul and Retrofit Capability of A400M Aircraft, and 2nd HBFM Aircraft FASBAT Directorate

The 2nd HBFM Aircraft FASBAT Directorate is the second source in the world for A400M Aircraft, apart from Airbus Defence & Space (ADS) Company, which has final assembly, DLM, and Retrofit facilities in Seville, and Getafe. Airbus A400M, one of the world's most advanced military transport aircraft, celebrated its 10th anniversary of service in Turkey last April. Turkish Air Force received its first A400M Aircraft in April 2014 and the 10th and last A400M Aircraft in March 2022. The aircraft, which has proven its reliability and effectiveness during the conflicts, the COVID-19 Pandemic, and natural disasters both in our country and around the world over the past 10 years, has proved to be a force multiplier and a valuable asset not only for the Turkish Air Force but also for Turkey's need for airborne humanitarian aid, and disaster aid/support. The A400M has demonstrated outstanding performance in Turkey since it entered service in 2014. As of April 2024, the A400M fleet of 10 aircraft within the Turkish Air Force has completed more than 15,000 flight hours (as of April 2019, this period was 4,000 hours) and achieved an impressive mission readiness rate of 75%. 

The 10th anniversary of the A400M in Turkey will be celebrated on April 16, 2024, at the 12th Air Transport Main Base Command, with the participation of representatives from the Ministry of National Defence (MSB), Secretariat of Defence Industries (SSB), Military Factory, and Shipyard Management Inc. (ASFAT), and Turkish Air Force representatives, as well as senior Airbus Defence & Space officials. Within the scope of the event, where the achievements of the A400M in the last 10 years and the capabilities of the aircraft were emphasized, Airbus and ASFAT signed a Memorandum of Understanding (MoU) confirming that it is the goal of both companies to further develop the Retrofit, and Maintenance operations at the 2nd HBFM Aircraft FASBAT Directorate for all A400M customers.

The 2nd HBFM Aircraft FASBAT Directorate was certified by Airbus Defence and Space (ADS) to provide D-Level Overhaul (C-Check) service for A400M Aircraft after a year-long inspection, and the certificate was presented at a ceremony held in February 2018. CL (Intermediate Level) and CH (Depot Level) maintenance have been carried out for A400M Aircraft by the 2nd HBFM since 2017. Of these, CL maintenance is done within 45 working days, and CH maintenance is done within 75 working days. Heavy Maintenance, which normally lasts 6 months, is carried out in accordance with EMAR-145 (European Military Airworthiness Requirements) standards, and the working personnel have the A400M Type Certificate. 

The A400M Aircraft Maintenance-Repair-Retrofit (Retrofit) Contract was signed between ADS and ASFAT at a ceremony held on October 3, 2019. The contract paved the way for the 2nd HBFM to provide retrofit services not only for the A400M Aircraft in the Turkish Air Force's inventory but also for the A400M Aircraft in the service of friendly and allied countries in the region. The 2nd HBFM is currently the only maintenance center in the world that can retrofit outside Airbus facilities.

By definition, retrofit is the reflection of the improvements resulting from user feedback and design changes on the aircraft during the period from the initial service of the A400M Aircraft until the aircraft is included in the retrofit (version upgrade) program. The 2nd HBFM is the only maintenance center capable of retrofitting outside Airbus facilities. The first retrofit activity, which started on December 7, 2020, was completed on July 30, 2021. Within the scope of the project, the second aircraft was delivered to the Turkish Air Force on April 7, 2022, and the third aircraft was delivered to the Turkish Air Force on October 27, 2022, after the completion of the retrofit works. While this capability was not available in Turkey, MSN-009 and MSN-013 were sent to Spain for both heavy maintenance and retrofit operations. While MSN-009 was expected to remain in Spain for approximately 6 months for maintenance, the maintenance process lasted approximately 1 year due to the buckling seen under the fuselage and wing, and that maintenance was quite costly for Türkiye. That experience actually revealed once again why Turkey needs to gain this level of maintenance capability, and since 2017, CL and CH maintenance for A400M Aircraft has begun to be carried out by the 2nd HBFM. While the maintenance-repair-overhaul operations on the A400M Aircraft are carried out in the hangar rented from the 12th Air Transport Main Base Command, the retrofit operations starting from the second aircraft were started to be carried out at the 2-bay A400M DLM Maintenance Center, which was put into service at the ceremony held on July 8, 2021. As of December 29, 2023, retrofit work on the 6th A400M Aircraft was ongoing in one of the halls at the A400M DLM Aircraft Maintenance Center, which has 2 separate slots that are similar to each other. Beginning with the 6th aircraft, C-Check Heavy Maintenance operations are also carried out simultaneously on the aircraft arriving for retrofit. The aircraft, which entered the A400M DLM Aircraft Maintenance Center on December 11, 2023, and was received by the Aircraft FASBAT Directorate, is planned to be delivered before June 7, 2024, if there are no problems or major malfunctions.

There are retrofit applications that include different capability standards (Standard of Capability/SOC) determined by Airbus Defence & Space Company for A400M Retrofit operations. In this context, there are three different levels of retrofit for A400M Aircraft: SOC 2, SOC 2.5, and SOC 3. While MSN-009 and MSN-013 were at SOC 1.3 and SOC 1.4 levels when they were first delivered to the Turkish Air Force, they were increased to SOC 2.5 level with the retrofit work. Since A400M Aircraft are delivered to the Turkish Air Force at different SOC standard levels, the Maintenance-Repair-Retrofit (Retrofit) work is not at the same level for each aircraft. Therefore, the retrofit packages of each aircraft may differ from one another. For example, Airbus initially gave a period of 6 months and then left a pocket for delivery of 2 weeks to ASFAT and 2 weeks to the customer (the Turkish Air Force). Airbus promised to deliver it completely to the SSB in a total of 7 months, then reduced this to 6 months for the second aircraft, and from the third aircraft, the Aircraft FASBAT Directorate has reached a level where it can deliver the aircraft in 4-4,5 months. If the 2nd HBFM Aircraft FASBAT Directorate can complete the Retrofit + C-Check Overhaul operations in this time, it will be completed in approximately 50% shorter time than the next best facility (ADS Sevilla facility). Such success would attract the attention of both Airbus and OCCAR and could open the door for international business. 

Military aviation is a sector with a very high added value, and the 2nd HBFM Aircraft FASBAT Directorate has many remarkable strengths in the sector, as it is an integrated facility with both maintenance/repair, part/component production, and renewal capabilities. Thanks to the close cooperation of the 2nd HBFM Aircraft FASBAT Directorate, which is in the process of entering the Authorized Supplier Catalog of Airbus Defence & Space Company, with ASFAT, which is almost a window of military factories and shipyards opening to the outside, with the acceleration of processes in bureaucratic terms, and by utilizing the existing facilities, and capabilities of friendly, and allied countries not only for Depot-Level maintenance, repair, and retrofit needs but also in the form of on-site maintenance/repair services (in any country where the A400M Aircraft is experiencing technical problems) through paid assignments, our country will earn significant amounts of foreign currency every year. 

The 2nd HBFM Aircraft FASBAT Directorate, which wants to be a maintenance center alternative for A400M users with a small number of aircraft, plans to acquire the A400M Paint Hangar in the coming years. If the targeted retrofit orders for A400M Aircraft from abroad are realized, it is envisaged that a new A400M Maintenance Center/Hangar will be built following the transition to a 24-hour double shift system in the first phase. 

2nd HBFM and Ground Support Equipment Production Capability

2nd HBFM has a very wide range of products including radar domes, radar, and aircraft paint (including paints used by aircraft during air shows), MJ-1TR Bomb Loading Device from F-16 Auxiliary Mission Equipment (YGT), SEYİT ONBAŞI (KOCA YUSUF-2) Bomb Loading Vehicle, and RAHVAN Aircraft Tow Truck, Ground Support Equipment such as Vehicles, and Aircraft Arresting Systems located in pairs at the beginning, and end of the runways (Maintenance/repair of all barriers in the inventory of the Turkish Armed Forces Command is carried out in the Barrier Workshop).

The KOCA YUSUF-2 Bomb Loading Vehicle (BYA) Project, which was launched on July 3, 2011, aims to design, manufacture, and maintain the bomb loading vehicle with domestic resources. The Project, whose name was changed to 'SEYİT ONBAŞI Bomb Loading Vehicle' on April 3, 2015, aims to produce a total of 70 SEYİT ONBAŞI (KOCA YUSUF-2) Bomb Loading Vehicles between 2016 and 2023. In this context, the last batch of 12 vehicles was manufactured in 2023. SEYİT ONBAŞI Bomb Loading Vehicle, which has a table lifting capacity of 1,360kg and a forklift capacity of 1,020kg, is different from the MJ-1 and MJ-1TR Bomb Loading Vehicles, and thanks to its remote wired control system as an additional capability, it provides the user with a safer, more precise, and easy uploading/unloading. 72% of the parts used in the SEYİT ONBAŞI Bomb Loading Vehicle, all parts of which are domestic except the engine, were manufactured in the 2nd HBFM facilities. SEYİT ONBAŞI Bomb Loading Vehicle, which has a 28hp capacity diesel engine and 360-degree rotation ability, weighs 1,800kg.

With the RAHVAN Aircraft Towed Vehicle Manufacturing Project, in order to overcome the maintenance, repair, spare parts supply, and design problems experienced in aircraft towed vehicles, all of which are of foreign origin, in the inventory of the Turkish Air Forces Command, it was started to manufacture RAHVAN, the first original design aircraft tow vehicle, which has easy maintenance/repair, easy to obtain spare parts, and was designed, and manufactured for the needs of the Air Force Forces units, with domestic facilities. Unit Function Tests of the manufactured prototype vehicles were carried out in different units and climatic conditions for 5 months and were successfully completed. Subsequently, the mass production process started, and within the scope of the Project, a total of 137 RAHVANs were planned to be produced in 3 different versions: Version 1, Version 2, and Version 3. In the first phase, the production of 90 vehicles was completed by 2020. Prototype development and production work for the serial production of the Version 3 type 47 RAHVAN Aircraft Towed Vehicle with additional capabilities has been completed, and the mass production process started in 2021. The vehicle, which has superior features compared to its foreign counterparts, can be used in aircraft shooting activities and ground support equipment weighing up to 80 tons in all climatic conditions. RAHVAN Aircraft Tow Vehicle, which is 4m long, 2.25m wide, and 2.65m high, weighs 5,600kg, has 4x4 traction features, and has a towing capacity of 60,000kg. Powered by TÜMOSAN product 4DT-39T-105C Diesel Engine with a capacity of 105hp (350nm torque), RAHVAN uses an automatic transmission, and thanks to the front and rear differential steering, the vehicle has a very high maneuverability (including crab driving). During our visit, we also had a short trip experience with RAHVAN. A significant contribution to the national budget was also made with the SEYİT ONBAŞI Bomb Loading Vehicle and RAHVAN Aircraft Traction Vehicle Projects