The J-7 fighter jet is a Chinese-built aircraft that began as a reverse-engineered version of the Soviet MiG-21, with significant local modifications distinguishing it from the original.

Initially, China entered into a licensing agreement with the Soviet Union in 1961 to produce the MiG-21, but after a breakdown in Sino-Soviet relations, China proceeded independently, reverse-engineering the design using limited and allegedly incomplete technical documents supplied by the Soviets.

Chinese engineers identified and addressed over 249 technical challenges, making several alterations that they officially documented in eight technical manuals.

The result was the J-7, first produced in the mid-1960s. Although its basic airframe and layout, with a swept delta wing and nose air intake, closely resemble the MiG-21F-13, the Chinese introduced several structural and mechanical changes.

For example, the J-7's hydraulic system and fuel tank placement were revised after Chinese engineers found that the original MiG-21’s configuration led to instability after about 45 minutes of flight because its forward-mounted fuel tanks compromised longitudinal stability. The J-7 repositioned fuel tanks and added larger external drop tanks, significantly improving flight stability.

The aircraft was powered by the WP-7 engine, a copy of the Soviet R-11 turbojet, and armed with a 30mm cannon similar to the MiG's NR-30. Early models had issues with ejection seats, prompting China to develop their own zero-zero ejection seats in later variants, such as the HTY-5, which allowed for safe ejections even at ground level.

Production and further development of the J-7 stretched for nearly half a century, repeatedly interrupted and delayed by domestic political turmoil, notably the Cultural Revolution. Large-scale, reliable mass production was only fully realised in the 1980s under Deng Xiaoping.

Through the decades, the J-7 evolved:

The J-7I closely matched the MiG-21F-13
The J-7II upgraded the ejection seat and engine
From the 1980s onward, later variants like the J-7M (developed with input from Pakistan) featured improved radar (including collaborations with British and Italian companies), better avionics, and expanded weapon compatibility, eventually matching the MiG-21 by the mid-1980s in capability
By 1987, the J-7E introduced a new wing, improved maneuverability by 45%, and Western technology such as HOTAS controls and helmet-mounted sights

The J-7 served as the backbone of the PLA Air Force before the widespread adoption of more advanced indigenous designs. It was also widely exported: Bangladesh, Pakistan (the largest foreign operator), Iran, Myanmar, Namibia, Nigeria, North Korea, Sri Lanka, Sudan, Tanzania, and Zimbabwe have all operated the aircraft. Bangladesh, for example, currently has about 36 F-7s (the export designation for the J-7).

The J-7's legacy is mixed. Despite improvements, it never fully shed its reputation for safety concerns, a criticism similarly levied against the MiG-21, sometimes nicknamed the "Flying Coffin" for its maintenance and crash history, especially as both airframes aged. The J-7’s enduring production line only ceased in 2013, but variants remain in operational use in several countries.

A recent reminder of the aircraft's risks is the tragic crash in Dhaka on July 21, 2025, when a Bangladesh Air Force F-7 training jet crashed into a college, resulting in 19 fatalities, including the pilot, students, and teachers. The incident underscores both the aviation safety challenges and the J-7's continuing, if diminishing, role in the air forces of developing nations.

Based On A NDTV Report