TURKISH TESTERS
- Aviation Features
- Turkish testers
18th October 2018
FEATURE
The demanding flight test requirements of the Turkish Air Force are met by 401 Filo, a specialist unit flying F-4s and F-16s from Eskişehir. Cem Doğut investigates its weapons trials work.
Flight test focus
An F-4E 2020 assigned to 111 Filo and carrying (from left to right): HGK, KGK, SOM and LGK-82. The latter is an indigenous version of the 500lb GBU-12 laser-guided bomb.
All photos Cem Doğut
Return to base for a SOMarmed F-4E 2020. This powerful cruise missile weighs around 1,300lb of which the warhead accounts for approximately 500lb.
As one of the final operators of the Phantom, the Türk Hava Kuvvetleri (THK, Turkish Air Force) has embarked on successive programmes to extend the jets’ service life and increase capability. As long ago as August 24, 1995 an agreement was signed with the then Israel Aircraft Industries (IAI) covering structural and avionics work on 54 F-4Es. Of these aircraft, 26 were upgraded at IAI facilities and the rest at the 1. Hava İkmal Bakım Merkezi (1. HİBM, 1st Air Supply Maintenance Centre), in Eskişehir. After modernisation, the Phantom was redesignated as the F-4E 2020 Terminator. The project also established a system integration laboratory and an avionics testing and integration centre at the 1. HİBM. Today, these facilities form the basis of 401 Test Filo – the THK’s dedicated test and evaluation squadron.
In 2004, the 1. HİBM began the Işık (‘light’) programme that provided 18 RF-4Es with a structural and avionics upgrade. Modifications included the installation of an Aselsan LN-100GT integrated inertial navigation system (INS)/GPS, Rockwell Collins CDU- 900Z flight management system, AN/ALQ- 178(V)3 electronic countermeasures system and MXF-484 VHF/UHF radios. The THK’s last RF-4Es were retired in March 2015.
This 401 Test Filo Phantom is carrying an example of the HGK-LAB – a dual-guidance version of the HGK, combining laser and GPS/INS functions.
F-16D Block 50 94-0106 and F-4E 2020 77-0300 prepare to depart Eskişehir for a test mission. The Phantom carries examples of the HGK-3, a 500lb version of the HGK and underwing fuel tanks with calibration markings applied, while the ‘Viper’ will serve as a chase aircraft.
The Phantom upgrade projects combined with the Common Configuration Implementation Program (CCIP, pronounced ‘c-sip’) for the F-16C/D, provided the 1. HİBM with valuable avionics testing and integration experience. On April 17, 2013 the 401. Geliştirme Test Kıta Komutanlığı (401st Development Test Battalion Command) was established to ensure that this experience was preserved and built upon.
The THK test squadron, 401 Filo, was established within the Technology and Weapon System Development Command and has operated under the jurisdiction of Eskişehir’s 1st Air Supply Maintenance Centre Command since 1996. On March 13, 2015 it received the title 401 Test Filo Komutanlığı (401 Test Squadron Command). The unit flies F-4E 2020 and F-16C/D aircraft equipped for test work. After the July 15, 2016 coup attempt, 401 Test Filo was reassigned to Eskişehir’s 1. Ana Jet Üssü (1st Main Jet Base).
F-16C Block 40 93-0001 ‘bombed up’ with inert 500lb Mk82s fitted with the Roketsan TEBER modular low-cost guidance kit.
SOM
Among the major projects developed with assistance from the squadron is the Tübitak SAGE SOM (Stand-Off Missile) family of ‘fire and forget’ precision strike weapons, for use against land and sea targets. The SOM uses GPS as its primary mode of guidance complemented by an advanced INS and a radar-based terrain-referenced navigation system, allowing the missile to hug the terrain during flight to evade hostile air defence systems.
According to the manufacturer, the SOM features more advanced aerodynamics and a better configuration than similar missile systems, as well as lightweight composite components to minimise its radar cross-section. A terminal stage infrared (IR) imager detects the individual target by matching its signature with a pre-loaded database of similar targets. The seeker can also be used to provide imagebased mid-course navigation by gathering imagery of waypoints and comparing them against the predicted position to update the navigation system. In this way, if GPS capability is denied or degraded, the missile can follow its waypoints using IR-based terrain updates. The missile includes a twoway datalink to reassign targets in flight.
The SOM cruise missile made a first guided flight over the Black Sea on August 9, 2011. Covering more than 100nm using GPS/ INS guidance, the missile successfully hit its target with a high degree of accuracy. Around 30 test flights were scheduled to assess the SOM and a first batch of missiles had been delivered to the THK by the end of 2011.
The SOM is available in three variants for air force use:
• SOM A: Basic variant designed to engage a military target in simple strike mode using preplanned co-ordinates at the terminal stage
• SOM B1: Advanced variant that engages a military target in precision strike mode using imaging IR matching at the terminal stage
• SOM B2: Special variant with dualstage penetrator warhead to engage strategic and well-protected targets
Precision kits
Tübitak SAGE has also developed the HGK (Hassas Güdüm Kiti, precision guidance kit), a state-of-the-art GPS/INS guidance package that converts an existing 500lb (227kg) Mk82 ‘dumb’ bomb into a ‘smart’ weapon. Integrated GPS/INS guidance allows the HGK to hit a target with a circular error probable (CEP) of less than 20ft (6m) in all weather conditions. An INS-only mode provides the HGK with a CEP of less than 33ft (10m). HGK can reach a range of more than 12nm when released from medium altitude. A maximum range of 15nm is achieved after release from high altitude.
Phantom 77-0300 returns to base carrying an inert HGK test round. In future, Turkey plans to integrate the HGK – and the SOM cruise missile – on the F-35A.
ASELPOD
The Aselsan ASELPOD is another store that has been tested by 401 Test Filo. It weighs 518lb (235kg) and is 7.7ft (2.35m) long. The electro-optical and infrared (EO/IR) sensors can track up to eight targets at a laserdesignation range of a maximum 15.5 miles (25km) and a general range of up to 34 miles (55km). The pod can track moving vehicles such as main battle tanks at 9.3 miles (15km). The pod has a third-generation IR camera with a zoom function and uses a 640x512 pixel detector. The ASELPOD can perform day and night and can be used alongside laser-guided and INS/GPS precision-guided munitions. Development of the ASELPOD is ongoing and includes work on a twoway data link. This will enable the pod to double as an intelligence, surveillance and reconnaissance (ISR) asset in addition to its principal role as a targeting pod.
An ASELPOD on an F-16C’s right intake station. The pod is externally almost identical to the Rafael Litening.
The Roketsan TEBER is a modular low-cost guidance kit that can be fitted to 250lb (113kg) Mk81 and 500lb Mk82 general-purpose bombs. It converts the bombs into precision weapons using INS, GPS and an optional laser seeker. The laser seeker provides a capability against moving, relocatable and maritime targets, even if the objective is manoeuvring at high speeds. The CEP is below 10ft (3m) and the weapon has a range of 17 miles (28km).
Penetrating bomb
Tübitak SAGE’s NEB (Nüfuz Edici Bomba, penetrator bomb) is the first concretepenetrator system developed in Turkey and is designed to be used against surface and underground targets.
Penetrating bombs generally use one of two methods for penetration. First are those that provide penetration power using kinetic energy. The BLU-109, for example, has a 1in-thick (2.5cm) steel shell and is detonated by a delayed fuze in the tail. The kinetic energy must be high for the bomb to be effective. The second method makes use of a shaped charge warhead. In contrast, the NEB uses multiple warhead technology: an augmenting charge preceded by a follow-through bomb. It has similar external geometry, guidance unit interfaces, mass, centre of mass and inertia properties as the 2,000lb (907kg) Mk84 generalpurpose bomb, but offers high penetration performance even with low impact velocities and angles. An augmenting charge utilises preformed fragments for high fragmentation effect against surface targets and programmable fuze delay times mean it can be used against various target types. The NEB can be used with all guidance kits compatible with the Mk84 and can be dropped from all aircraft cleared to carry this bomb. Guidance options include the HGK and the GBU-10E/B laser guidance kit.
Wing kit
The Tübitak SAGE KGK (Kanatlı Güdüm Kiti, glide bomb kit) is a wing-assisted guidance kit that converts existing unguided 1,000lb (454kg) Mk83 and 500lb Mk82 generalpurpose bombs into long-range, air-to-ground smart weapons. The KGK employs the same guidance system as the HGK and can hit a target from a range of 62 miles (100km), in all weather conditions, allowing the launch aircraft to attack while avoiding enemy air defences.
Originally published in AirForces Monthly Magazine
