Hongdu JL-8
The Hongdu JL-8 (Nanchang JL-8), also known as the Karakorum-8 or K-8 for short, is a two-seat intermediate jet trainer and a light attack aircraft designed in the People's Republic of China by China Nanchang Aircraft Manufacturing Corporation. The primary contractor is the Hongdu Aviation Industry Corporation. Development. The JL-8 trainer was proposed as a joint cooperation effort between the governments of Pakistan and the People's Republic of China in 1986. The name was changed on the suggestion of Pakistan's then President Zia ul Haq to Karakoram-8 to represent the friendship between the two  countries. Work on the design started in 1987 at Nanchang Aircraft Manufacturing Company (NAMC) at Nanchang, Jiangshi Province in South Central China. The Chinese chief designer of the aircraft was Shi Ping (), heading a team of over 100 Chinese Engineers, while Air Cdr Muhammad Younas Tbt (M), SI(M) was the chief designer from the Pakistani side leading a team of over 20 Pakistani engineers. Initially, the aircraft was to feature many parts manufactured in the United States, including Garrett TFE-731 engine and several cockpit displays along with communication and avionics systems, but due to political developments and an embargo from  the US at the end of the 1980s following the Tiananmen Square protests of 1989, other suppliers had to be used. The first prototype was built in 1989, with the first flight taking place on 21 November 1990 by Chief Test Pilot Col Yang Yao (). Flight testing continued from 1991 to 1993 by a Flight Test Team consisting of four Chinese and two Pakistani pilots. After four prototypes were built, production of a small batch of 24 aircraft was launched in 1992. The Chinese share out of these was 18, while the Pakistan Air Force (PAF) received six K-8s in  1994. In 1995, the PAF decided to order 75 more K-8s to gradually replace its fleet of Cessna T-37 Tweet basic trainers. In 2010, the number of K-8 aircraft in the PAF inventory was estimated to be around 40. The People's Liberation Army Air Force (PLAAF) received its first six JL-8 trainers in 1995 following additional upgrades. The Chinese model uses a Chinese-manufactured version of the Ukrainian Ivchenko AI-25 (DV-2) engine, designated WS-11. The PLAAF is anticipated to continue adding the JL-8 trainer to its fleet to replace its obsolete trainers, such as the Chengdu JJ-5. In 2008 , the number of JL-8s in PLAAF inventory was estimated to be over 120 aircraft. Other countries have shown interest in the trainer and it now also serves in the air forces of Egypt, Sri Lanka and Zimbabwe. While the type primarily serves as a basic and advanced trainer, it can also be used in the close air support or even air combat role when appropriately armed. The export-variant K-8 Karakorum Basic Common Advanced Jet Trainer is co-produced by China National Aero-Technology Import & Export Corporation (CATIC) for export markets other than Pakistan, while later aircraft for Pakistan have  been built by the Aircraft Manufacturing Factory (AMF), Pakistan Aeronautical Complex. The latest export variant is the K-8P version, which currently is operated by the PAF. The K-8P has an advanced avionics package of integrated head-up display (HUD), multi-function displays (MFDs) and comes equipped with MFD-integrated GPS and ILS/TACAN systems. It also features hardpoints for carrying a variety of training and operational bombs up to 250 kg, pod mounted 23 mm cannon as well as PL-5 / 7 /AIM-9 P launchers. In September 2011, NAMC rolled out another 12 K-8P for an undisclosed foreign client. In 2008  Venezuela announced the purchase of 18 K-8 aircraft. The K-8 has been marketed by China to the air forces of the Philippines , and to Indonesia, as a replacement for Indonesia's BAE Hawk jet trainers. In 2009, the Bolivian government approved a deal to purchase 6 K-8P aircraft for use in anti-drug operations. In 2010 the total number of K-8 aircraft produced in all variants was estimated to be more than 500, with a continual production rate of approximately 24 aircraft per year. Design. The JL-8 / K-8 has a multi-role capability for training and, with little modification, can  also be used for airfield defense. The aircraft is supposed to be as cost-effective as possible, with a short turn-around time and low maintenance requirements. The JL-8 for the domestic Chinese market and its export variants, K-8E and K-8P, have different powerplants and avionics. Airframe and flight control system. A low-wing monoplane design primarily constructed of aluminum alloys, the JL-8 / K-8 airframe structure is designed for an 8,000 flight hour service life. The landing gear is of tricycle configuration, with hydraulically operated wheel brakes and nose-wheel steering. The flight control system operates a set of conventional  flight control surfaces with a rigid push-rod transmission system, which itself is electrically or hydraulically operated. The aileron control system, of irreversible servo-control type, is composed of a hydraulic booster, an artificial-feel device, a feel trim actuator and a rigid push-rod transmission mechanism. The elevator and rudder control systems are of reversible push-rod type. Cockpit and avionics. The JL-8 / K-8 cockpit arrangement is designed to be as close to that of a combat aircraft as possible. A transparent plastic canopy covering both cockpits, which are arranged in a tandem seating position, is supposed to give  a good all-round field of view. A Rockwell Collins Electronic Flight Instrument System (EFIS) is fitted, with multi-function displays (MFDs) in the front and rear cockpits showing information to the pilots. The emergency cockpit escape system is made up of two Martin-Baker MK-10L rocket-assisted ejection seats which are zero-zero capable, meaning they can be used safely at zero altitude and zero speed. Although JL-8 is designed to have limited capability to deliver air-to-ground weapons, the first rocket attack practice was only completed in May 2011. Ultra high frequency (UHF) and very high frequency  (VHF) radio communication systems are present, along with a Tactical Air Navigation (TACAN) and automatic direction finder (ADF). An instrument landing system (ILS) is also available. These systems can be tailored to meet the requirements of the customer. A strap-on Environmental control system (ECS) from AlliedSignal provides air conditioning to the cockpit. It is capable of operating when the aircraft is on the ground, under ambient temperatures of -40 to +52 °C, as well as in the air. Propulsion and fuel system. The JL-8, for the Chinese domestic market, was originally powered by the Ukrainian Ivchenko-Progress AI-25TLK  turbofan jet engine with 16.9 kN of thrust, but this has been replaced by the WS-11, the Chinese-manufactured version of the AI-25TLK. Export variants (K-8P, K-8E) use the lower-thrust (15.6 kN) Honeywell TFE731-2A-2A modular turbofan, which has digital electronic engine control (DEEC), provided the US government approves sale of the engine to the customer. A hydro-mechanical fuel control system delivers fuel to the engine. The aircraft's fuel system consists of the fuel tanks and the fuel supply/transfer, vent/pressurization, fuel quantity measuring/indicating, fuel refueling and fuel drain subsystems. The total fuel is contained  in two fuselage bladder-type rubber tanks and a wing integral tank of 1720 lb. The capacity of each drop tank is 250 litres. Operational history. The K-8 took part in its first aerial display in 1993 at the Singapore Air Show and since then has participated at Air Shows at numerous places including Dubai, Paris, Farnborough, Bangkok, Zhuhai etc. It was shown to the Pakistani public for the first time on 23 March 1994 at the Pakistan Day Parade. It became part of the Sherdils (Lion Hearts) aerobatics team of the Pakistan Air Force in 2009 and carried out  its first public display on 6 April 2010. K-8 replaced the team's previous T-37 Tweet aircraft. Myanmar. In late December 2012 and early January 2013, during the Kachin conflict, K-8s of the Myanmar Air Force were used to strike Kachin Independence Army positions in the north of the country.