The box was opened very simply!
Yes, the answers are a classic riddle killer. Andreas Ruprecht, an expert on Chinese aviation, known under the nickname RupprechtDeino on various social networks and instant messengers, has done some very interesting work and dispelled the fog of war over one of the mysteries about which much has been written.
In 2022, a satellite image emerged showing objects resembling fighter jets and very similar (but not identical) to the stealthy J-20 at a Chinese airbase, let's say, located at a significant distance from populated areas.
Three years later, in 2025, another image emerged, showing a similar yet noticeably different object at another airport in China. The global aviation community was truly in a frenzy, baffled by the speculation about what had been captured by satellite cameras.
Many (including ourselves) began speculating and theorizing about what these objects might be. Generally, the international community agreed that anything could be expected from China, including the development of several projects simultaneously. The distance from the aerospace centers was explained by both the Chinese love of secrecy (which is not at all a bad thing) and the fact that aerospace centers are under extremely close surveillance.
It's worth admitting that we were… a little mistaken. The calculations were quite well thought out, but they differed from reality in a completely different way.
The mystery of these objects has been at least partially solved thanks to new photographs of a mock-up used for airfield firefighting training.
Images of the firefighting simulator are currently circulating on social media, but it's not yet clear where and when they were taken. The markings on the runway differ from those on the concrete at Lintao Air Base, where gliders were spotted as early as 2022, and at Qufu Airport in Jining, where another object was spotted in 2025.
A photograph showing training using the aforementioned flight simulator
The overall design of the trainer, vaguely reminiscent of the J-20, also more closely matches the object previously spotted at Qufu Airport in Jining. Both aircraft share a distinctive diamond-shaped airframe, as well as canards and twin vertical stabilizers. It's worth noting that the available images also reveal a cockpit configuration more typical of the new J-35. However, the aircraft spotted at Lintao had different wing shapes, and longer, thinner noses.
From left to right: One of the "forms" spotted at Lintao Air Base in 2022, an object spotted at Qufu Airport in Jining in 2025, and a trainer aircraft vaguely resembling a J-20.
In general, training mock-up aircraft can be any aircraft that remotely resembles the desired type of aircraft: a fighter, an airliner, etc. From specially designed systems to converted airframes of old aircraft.
Training aids of this kind are designed to be easily reused to add realism to airfield firefighting training. They are widely used worldwide by national armed forces and civilian fire departments. The figures previously seen in Lintao may still serve other purposes, such as full-scale mockups or decoys.
For example, they act in exactly the same way in many countries around the world.
An American military flight simulator in the form of an F/A-18 Hornet fighter jet.
A simulated aircraft fire training aircraft is designed to resemble an F-35 Joint Strike Fighter at Hill Air Force Base in Utah.
The development of the firefighting simulator also comes as the People's Liberation Army Air Force (PLAAF) fleet of real J-20s continues to expand. According to some estimates, the PLAAF may have approximately 500 J-20s in service, distributed among at least 14 combat units and three training bases.
According to some forecasts, the total fleet could reach 1000 aircraft by 2030 if production continues at the current rate. This includes all variants, including the two-seater version, which was first unveiled in 2021.
One of China's growing fleet of J-20 fighter jets
The growing fleet of Chinese J-20s, as well as other more modern fighters, can only increase the need for training for both pilots and ground crews, as well as maintenance and repair. The greater the number of scheduled sorties, the higher the risk of crashes and other accidents.
Chinese firefighters at an airfield approach a simulator.
Another close-up: Chinese firefighters at the airport hose down a simulator.
It's all very logical and nothing new: extinguishing an aircraft fire is a complex process that requires special preparation. A combat aircraft is a highly complex machine, significantly smaller than a civilian aircraft and carrying weapons. Therefore, different extinguishing agents are used at different times.
Air-mechanical foam (AMF) of low or medium expansion.
It's ideal for extinguishing jet fuel spills: the foam covers the surface, isolating the fire from oxygen and simultaneously cooling it. It's delivered through the nozzles of fire trucks, allowing fuel spills to be extinguished from a safe distance.
Aqueous solution of foaming agent.
It's also used to extinguish liquids, but for a different purpose. For example, this solution is used to extinguish hydraulic fluid and tire rubber. It's excellent for cooling aircraft structural components to prevent deformation. Sometimes, finely atomized jets with short pulses are used—this is especially important when extinguishing landing gear: this prevents tire rupture due to sudden heating. This is essential when extinguishing aircraft with large wheels, where tire ruptures can cause both structural damage and the scattering of burning parts and fuel. A tire rupture is comparable to the explosion of a hand grenade.
Powder compositions.
They are used when specific materials are burning. For example, magnesium alloys, which are used to make brake drums, wheel rims, fuel, oil, and hydraulic system housings, pump housings, gearboxes, crankcases, and much more. These types of components should not be extinguished with water, as a dangerous reaction with hydrogen production is possible, which would only intensify the fire.
The powder forms a sintered crust on the surface, blocking oxygen access. A combination method is often used: first applying the powder, then cooling with water or foam.
Gas, mainly carbon dioxide.
Can be used in closed, highly sealed compartments. The heavier CO2 displaces the oxygen needed for combustion, thereby quickly stopping the process.
Combinations of several extinguishing methods can be very effective. The process itself is complex, as the fire commander (called the fire chief) must keep in mind numerous aircraft design nuances: the location and fill levels of fuel tanks, oil tanks (many aircraft and helicopter gas turbine engines use oil for lubrication), and hydraulic fluid tanks. Internal weapons bays are a definite headache during a fire, as ammunition there is more difficult to cool and protect from secondary detonation than on external slings.
Bottom line: learning about firefighting options and practicing approaches is normal. Everyone does it.
So, the object spotted at Qufu Airport in Jining in 2025 can now, with a high degree of probability, be considered a fire simulator. In recent years, China has seen an increasing number of new, truly modern aircraft models appear. These include manned and unmanned aerial vehicles of all shapes and sizes, from the new-generation J-36 and J-XDS fighters to various streamlined combat aircraft. drones and several types of unmanned flying wings.
As China's fleet of more advanced combat aircraft expands, we can expect a similar increase in the infrastructure and other resources needed to operate them, including new simulators for practicing airborne gunnery.
Of course, it's a bit of a shame that our conclusions from last year turned out to be wrong, but I'm sure the Chinese will still have many more surprises in store for us. At least, work on this in China continues.
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