Indian Analyst Claims J-20 May not Perform as Well in High Altitudes

The Study 

In 2021, China’s Chengdu Institute of Aviation Industry tested the Chengdu J-20 Mighty Dragon at the Tibetan Plateau, testing flight capabilities in higher altitudes. The J-20 likely took off from Daocheng Yading Airport, which rests at 13,123 feet (4,000 meters) above sea level.

Abhijit Lyer-Mitra, a researcher with the Institute of Peace and Conflict Studies, claimed the J-20 could lose 60-70 percent of its power, notably takeoff weight and payload capacity. Lyer-Mitra’s data reportedly found the J-20 may have performance issues at higher altitudes, possibly due to thinner air reducing the thrust put out by engines, leading to a loss of power.

Four J-20s at a 2022 Airshow. Source: Cui Meng/GT

The same study also suggests runways within Tibetan Plateau may not be the most ideal for the J-20, as the size and weight, as the maximum takeoff weight is around 74,000-88,184 lbs. or 33,565-39,999 kg. The single wheel design of the J-20 could also lead to more wear on the gear due to the rougher environment on the runway.

If the J-20 were to carry a maximum payload, 24,250 lbs. or 11,000 kg, in similar altitudes, could be questionable, given the lower thrust produced under the rough conditions. This would also lower the J-20’s overall effectiveness during missions.

Further testing will likely be needed to fully gage the J-20’s effectiveness in similar harsh regions.

The Mighty Dragon 

The Chengdu J-20 is a fifth-generation stealth air superiority fighter based on the J-XX program from the 1990s, currently in service with the People’s Liberation Army Air Force (PLAAF) in 2017.

The J-20 can travel at Mach 2 and has a combat range of 1,200 miles (1,931 km) and a maximum service ceiling of 66,000 feet (20,116 meters).

J-20 with what looks like training equipment. Source: Sina Weibo

The main variant currently in service is the J-20A, the first variant to go into production. An upgraded B variant is reportedly in production as a prototype was spotted in December 2022. The B variant seems to feature a raised cockpit, reshaped nosecone, different engine intakes, and possibly upgraded WS-15 engines.

A two-seater prototype was spotted in October 2021, and this is referred to as the J-20S variant.

The armaments consist of short to beyond visual range Air-to-Air Missiles and precision-guided bombs. The J-20 reportedly lacks a cannon, the J-20 is reportedly not designed for shorter-range dog fights.

Other features of the J-20 consist of Active Electronic Scanned Array (AESA) radar, Electro-optical Targeting System (EOST), and a radar cross-section comparable to the American F-117 Nighthawk stealth attack aircraft and the B-2 Spirit stealth bomber.


The data from this study could be applied to improving the J-20 airframe, especially with the current model of engines inside the A variant, to make it a more capable fighter aircraft. Additionally, this could be transferred to other stealth aircraft especially if shown to suffer from similar issues in field testing, such as the J-35 among others in the PLAAF fleet.

Improving this issue will prove to be beneficial to the J-20 as it will have increased performance at higher altitudes in combat or out of it, and points out the fact that the A variant may use a weaker engine that needs to be replaced. Fighter aircraft often operate at higher elevations, which the J-20 must be able to do.

The Chinese researchers may have taken this data and applied it in making the B variant, as the B variant features a newer WS-15 engine. This new model is said to be more powerful, potentially solving this issue, and any other issues the Chinese ran into with the A variant.

Although this study may point out legitimate flaws with the J-20, the source is from an Indian-based source, which could carry a hint of bias. Indian news outlets have published material claiming certain deficiencies with the J-20, often without credible evidence in an effort to discredit the J-20.

Evan Berridge
Evan Berridge
Analyst reporting on mostly Indo-Pacific affairs, covering a wide variety of topics. Started in January 2024


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