In May of this year, a foreign aviation instrument company announced that it had developed an airborne collision avoidance system suitable for multiple aircraft models. This system can effectively detect changes in the environment around the aircraft and display various symbols and colors through the aviation instrument panel, helping the aircraft avoid dangers with the optimal plan. As a true "recorder" of a fighter jet's flight status information, instruments can guide pilots to make correct judgments and operations in various flight environments, providing strong support for safe flight. Since World War I, with the rapid development of science and technology, aviation instruments have been continuously updated and iterated, evolving from the earliest mechanical instruments step by step into electronic integrated display instruments. Although aviation instruments are small in size, their design and manufacturing requirements are extremely precise. Their key core technologies test a country's aviation electronics industry manufacturing level. Looking at the development of aviation instruments from a global perspective, what are their core functions? What are the manufacturing difficulties? How should they be maintained later? Besides aviation instruments, what other instruments and meters are there on airplanes or rockets? Please read this article for detailed explanations one by one. ### Recording the Pulse of Information: "One Instrument, Multiple Uses" at a Glance Modern fighter jets are gradually evolving towards high speed, high maneuverability, and multi-mission capabilities, and the flight environment is becoming increasingly complex. The role of aviation instruments is crucial in accurately grasping the flight status of fighter jets under complex flight conditions. In the early days, when human flight was still in the exploratory stage, scientists did not design special instruments for fighter jets. During the Wright brothers' first flight, the "Flyer 1" aircraft only had a stopwatch, an anemometer, and a tachometer, which could only feedback extremely simple flight parameters. Pilots needed to judge changes in flight status based on their own experience. War gave birth to new equipment. During World War I, the British S.E.5 fighter was equipped with 3 special flight instruments and 4 engine instruments. However, pilots still mainly relied on visual observation of the flight environment, and the instruments only served as a flight auxiliary tool with very limited functions, failing to play a substantial role. This way of flying did not last long. As the flight speed and altitude of fighter jets continued to increase, scientists found that relying solely on naked-eye observation, it was difficult for pilots to judge the flight status in a short time. In severe weather such as heavy fog and thunderstorms, flight accidents could even occur due to misjudgment. They realized that flying with instruments was imminent. In 1929, aviation instruments finally ushered in a "highlight" moment. American pilot Doolittle covered the cockpit with canvas and conducted a flight test completely based on instrument data without seeing the external flight environment. This "covered" instrument flight was a miracle and became a new milestone in the history of aviation technology development. Instruments during this period were mainly mechanical and electrical. Due to limited technical capabilities, problems such as low sensitivity, large indication errors, and poor anti-vibration stability were gradually exposed, forcing scientists to rack their brains to start a new round of innovation. In the 1950s, aviation instruments developed into the second generation, with various electromechanical servo aviation instruments and sensors appearing, featuring lower failure rates, higher precision, and stronger signal transmission. However, the second-generation aviation instruments also exposed a fatal problem - with the increasing number of airborne equipment, the number of instruments increased significantly, making the instrument panel overcrowded, which greatly interfered with pilots' reading of data. Therefore, the clever combination of functionally related instruments became an inevitable trend in the development of aviation instruments. The concept of "one instrument, multiple uses" was soon applied to the research and development of the third-generation instruments. Before long, electromechanical integrated instruments represented by integrated compass indicators and combined horizon indicators were successfully developed and used until the end of the 1960s. Technology spawned changes, and the trend of aviation instruments becoming more technological emerged at this time. With the rapid development of electronic technology, new optoelectronic components such as liquid crystal displays and light-emitting diodes came out one after another, and aviation instrument technology entered the fourth generation. On the basis of the third-generation "one instrument, multiple uses" concept, scientists developed electronic display screens through information and data integration, which gradually became the new protagonists on the instrument panel. For example, the U.S. military's F-35 fighter jet was the first to adopt a large-size, multi-functional touch color liquid crystal display, allowing pilots to "see at a glance" various key information. Advanced display technology has made aviation instruments one of the most sophisticated and expensive equipment on fighter jets, and also a significant symbol to judge the advanced nature of fighter jets. ### Instruments Meet "Black Technology": Trendy Products of the Era As the performance of fighter jets iterates and improves, pilots need to master more and more flight parameters, which puts forward higher requirements for the output function of aviation instruments. The modern aviation instrument "family" is large and diverse. According to their functions, they can be divided into 4 categories: flight instruments that indicate the flight parameters of the fighter jet, engine instruments that detect the working status of the engine, navigation instruments that indicate the position of the aircraft relative to the Earth, and status instruments that indicate the operation of the fighter jet's operation, air conditioning, power, and hydraulic systems. The instruments cooperate tacitly and can provide a huge amount of flight data. The display of the "Super Hornet" fighter can present 62 kinds of screens, more than 600 different symbols, and the combinations exceed 1,000 kinds of information, providing important guarantees for the flight safety of the fighter jet. As a true "recorder" of fighter jet flight data, one of the most important performances of instruments is to ensure the accuracy of displayed parameters. Modern aviation instruments integrate a series of "black technologies" such as sensing technology, quantum mechanics technology, and intelligent technology, becoming one of the core systems of fighter jets. Take the gyroscope as an example. It is one of the most sophisticated and technologically advanced instruments on a fighter jet, capable of providing pilots with a series of information such as the precise orientation, pitch, position, and speed of the fighter jet, and its importance is self-evident. Since the birth of the gyroscope, its research and development and manufacturing process have always been cutting-edge core technologies. At present, only a few countries in the world have the ability to research, develop, and manufacture gyroscopes. Early gyroscopes were mostly mechanical, and later developed into optical gyroscopes. To meet the needs of aviation equipment performance monitoring, various advanced technologies have been applied to the research and development of gyroscopes. After years of research by scientists, a kind of gyroscope called Micro-Electro-Mechanical System (MEMS) was successfully developed. As the name implies, the "micro" system integrates a series of components such as sensors, signal processing, and circuits into a small system, with many advantages such as intelligence, miniaturization, and integration. It is very suitable for mass production and was soon favored by military enterprises of various countries. So, how is the MEMS gyroscope produced? Taking a foreign MEMS gyroscope as an example, different from the "gyro" shape imagined by most people, it combines advanced microelectronics technology and micro-processing technology, adopts mature processes in semiconductor production, and integrates mechanical devices and electronic circuits on a silicon chip almost the size of a fingernail through a series of processes such as circuit production, bonding, and annealing; after a series of strict tests such as signal testing and calibration, it can be officially put into use. In addition, to prevent internal high temperature, humidity, and some high-speed flight pollutants from entering, designers usually choose materials such as sealing rings and rubber tubes to seal the product through processes such as sealing glue and welding, so as to extend its service life and prevent material corrosion. MEMS gyroscopes not only play a major role in military fields such as fighter jets but also are widely used in civil fields such as smartphones, intelligent driving, and drones. With the continuous increase in human demand for intelligent electronic devices, MEMS gyroscopes have gradually become trendy products leading the era. ### From "Suspected" to "Confirmed": The "Barometer" of Fighter Jet Health Aviation instruments, as pilots' "right-hand men", play an extremely important role in wars. However, the function of aviation instruments is far more than that. Back on the ground, the instruments turn into an important tool for fighter jet maintenance personnel to debug the fighter jet. It can be said that it is the "barometer" of fighter jet health. In the overhaul factory, when a fighter jet enters the final assembly and debugging stage, "fighter jet doctors" often debug and repair abnormal indicators according to the parameters displayed by the instruments. For a fighter jet to return to the sky, it must obtain the "approval" of the instruments before it can go through the "discharge" procedures. Obviously, both pilots and maintenance personnel must judge the performance status of the fighter jet based on the feedback data from aviation instruments. If the aviation instruments themselves are "on duty with illness", they will provide wrong parameters. Operating and debugging the aircraft according to the wrong parameters can easily lead to major accidents. In this case, ensuring the "health" of aviation instruments becomes particularly important. Modern aviation instruments have complex structures and precise circuits, and are prone to failures due to component aging, transportation bumps, etc. Different from mechanical systems, circuit signals are invisible and intangible, making it extremely difficult to judge the location of "lesions", which brings great challenges to maintenance work. In the actual application process, researchers and maintenance personnel have never stopped exploring the maintenance methods of aviation instruments. In long-term practice and exploration, a systematic maintenance method has gradually been formed, which can be summarized into the following three steps: The first step is to reproduce the fault. When a fault occurs in an aviation instrument, in order to quickly and accurately identify the fault information, maintenance personnel usually simulate the normal working environment of the electronic instrument, restore the scene where the fault occurred, find the "cause of the disease", and prevent "misdiagnosis". The second step is to isolate the fault. After a preliminary judgment and analysis of the "cause of the disease", maintenance personnel will mark and isolate the suspected problems, cut off the connection with other components, and avoid local faults from causing larger-scale "complications". In the isolation area, maintenance personnel will gradually check to further narrow down the scope of the "disease". The third step is to eliminate the fault. After narrowing down the scope of the "disease", conduct a carpet search according to the process characteristics, internal structure, and fault performance of the instrument. Maintenance personnel will turn "suspicions" into "confirmed diagnoses" by replacing components, checking circuit solder joints, etc., and take targeted "treatments" until the fault is completely eliminated. Does the elimination of faults mean that the fighter jet has recovered its health? Of course not. To ensure that everything is safe, before the fighter jet takes off, maintenance personnel and pilots must re-inspect and debug the instruments and equipment, check various hidden dangers one by one, and after a series of "re-examinations" and all indicators are qualified, the fighter jet can successfully leave the factory. ### Instrument Panel Vibration Damper: Calm in All Situations As a load-bearing component of the spacecraft's instrument equipment, the overall frame structure of the instrument panel is like a "house", which not only provides independent "private space" for "family members" such as instrument display equipment and main manual control equipment but also provides accurate and reliable installation interfaces for them. This "house" of the instrument panel is reliably connected to the spacecraft's cabin wall through four metal rubber vibration dampers. These four metal rubber vibration dampers are just like four "safety guards in soft armor", which structurally have both the inherent characteristics of metal and the unique elasticity of rubber, thus ensuring the stable and reliable operation of the instrument equipment. When the spacecraft encounters huge vibrations, impacts, and other scenarios during launch, flight, and return, the four metal rubber vibration dampers can provide a necessary and reliable mechanical working environment for the instruments and equipment on the spacecraft. For example, during the launch and return of the spacecraft, they ensure that the equipment is intact; and during the flight of the spacecraft, they improve the mechanical working environment of the equipment on the instrument panel. ### What Other Instruments and Meters Are There on Airplanes or Rockets Besides Aviation Instruments? #### The Evolving "Black Box" The official name of the "black box" is the flight recorder. Each civil aircraft is equipped with two "black boxes", namely the "Cockpit Voice Recorder" (CVR) and the "Flight Data Recorder" (FDR). Since the 1960s, when they were applied to civil aircraft, "black boxes" have become an indispensable important safety device for global civil aviation operations. The prototype of the "black box" appeared in the early 1940s. In 1939, the Frenchmen François Hussenot and Paul Beaudouin made the earliest recording attempt with their invented "HB type" flight recorder. Hussenot later founded SFIM, which later became part of Safran. The "HB type" flight recorder is essentially a miniature camera, which can take pictures of the data on the aircraft instrument panel on an 8-meter-long and 88-millimeter-wide rolling photographic film. Since then, until the 1970s, the French Flight Test Center has been using this "HB type" flight recorder. Flight recorders based on photography principles have the advantages of no need for decoding and immediate viewing, but the film also has defects such as flammability, non-erasable records, and non-reusable, so they are mainly used during aircraft test flights. In the 1960s, governments and civil aviation management departments of the United States, Britain, Australia, and other countries successively issued regulations requiring all commercial aircraft to carry flight recorders. Since then, flight recorders have gradually become standard equipment for civil aircraft worldwide. From the 1960s to the 1990s, the core storage medium of most flight recorders was magnetic tape. After the 1990s, with the emergence of solid-state storage devices, the magnetic tape in flight recorders was also replaced by smaller and easier-to-preserve data recording boards. Subsequently, the storage capacity of flight recorders also increased exponentially, and they can record more and more data. Now, many global aviation airborne equipment manufacturers produce and supply flight recorders. #### Cabin Door Rapid Leak Detector: A Reassuring Instrument In the space station mission, astronauts need to enter the core module of the space station from the Shenzhou XII spacecraft, and during this period, they have to go through multiple cabin entry and exit activities, all of which require opening and closing the cabin door. The gas that maintains the survival of astronauts in the cabin must not leak, and whether the cabin door is well sealed is decisive. Therefore, quickly and accurately detecting the tightness of the cabin door is crucial. The cabin door rapid leak detector can be called a powerful "magic weapon" to ensure the safety of astronauts' extravehicular activities. The function of the cabin door leak detector is to detect whether the cabin door of the Shenzhou spacecraft is sealed. It relies on its internal core sensing system to sense changes in pressure and temperature, quickly judge whether the cabin door is closed properly in a very short time, and provide astronauts with the instruction "The cabin door is closed, you can take off the spacesuit", allowing astronauts to safely control Shenzhou XII to soar in space and provide reliable safety guarantees for astronauts' activities in the cabin. Source: MEMS, Kan Hangkong, Yishang Wang