A fighter jet has been repaired for 4 years?
Yes, the U.S. military recently revealed that a fifth-generation F-22, which was damaged as early as 2018, is expected to return to service this year.
It is understood that when the fighter took off, due to a data calculation error, the landing gear was retracted in advance, and it was damaged by taxiing on the runway by rubbing the belly.
As we all know, the fifth-generation aircraft has the characteristics of super stealth, supersonic cruise, and super maneuverability. Whether it is R&D, manufacturing or maintenance, it takes into account the technical level of a country's aviation industry.
Easy to use does not mean easy to repair. The stealth coating is fragile and the system structure is complex... Since the advent of the fifth-generation aircraft, aviation maintenance technical problems have come one after another.
So, how difficult is the maintenance of the fifth-generation machine?
How did foreign military enterprises break through these technical difficulties?
How hard is it to build an advanced fighter jet?
■Song Ru Xu Yang
Regular "makeup" -
One hour of scenery, "makeup" all day and night
In the magical world, there is a magical cloak, which can be invisible by wearing it.
With the rapid development of aviation technology, the first change of the fifth generation aircraft is its own powerful stealth function.
The reason why the fighter can be invisible is that in addition to having a pair of special "skins and bones", it also relies on its custom-made "beauty"-stealth coating.
Radar is known to detect fighter trails by emitting and receiving radar waves.
The role of the stealth coating is to absorb radar waves, so that the opponent's radar cannot receive the flight information of the fighter.
Just like the delicate skin in the game can enhance the player's combat power, the stealth coating significantly enhances the stealth ability of the fifth-generation machine.
In order to make the "makeup" more refined, aviation designers have taken great pains to select and use "makeup" materials.
They use iron oxides and polymers as raw materials, and generally paint the fuselage in 3 layers.
The number of coatings can even reach 10 layers in the air intake and other parts that are severely impacted by the airflow.
However, although the fifth-generation machine wrapped in layers has good stealth performance, the cost of "beauty" is beyond imagination.
The durability of the stealth coating is poor, and it may even cause an "allergic reaction" to rainwater. After supersonic flight under harsh conditions, the situation of "removing makeup and powder" occurs from time to time, and the stealth performance is also weakened.
To make matters worse, affected by the airflow, once the coating falls off during flight, it can easily be sucked into the engine, causing serious flight accidents.
"Make-up" can be done anytime, anywhere.
Taking the F-22 fighter jet as an example, it takes more than 20 hours of maintenance every 1 hour of flight. It can be described as "one hour of scenery and one day and night of makeup". The maintenance personnel spend half of their working time every day repairing and coating the fighter jet. All have to be repainted from time to time.
The "makeup" environment is extremely harsh.
Environmental factors such as moisture, temperature, and humidity are very demanding, and fighters are not even allowed to park in the open air.
Some data show that if exposed to direct sunlight for a long time, the coating will gradually crack and eventually fall off in pieces.
Each fifth-generation machine has an independent room - constant humidity and constant temperature air-conditioning hangar to ensure that the environment meets the standard and prevent the coating from falling off.
The cost of "makeup" has skyrocketed.
According to statistics, the cost of F-22 fighter jets per hour of flight is as high as 50,000 US dollars, and each replacement of the stealth coating costs nearly one million US dollars. The high maintenance costs make it difficult for the military of many countries to bear.
Fix bugs -
"Congenital" is insufficient, and "acquired" is modified
In 2011, the birth of the fifth-generation U.S. military aircraft F-35 attracted worldwide attention.
The F-35 inherits a large number of advanced technologies from the F-22 and achieves generalization to the greatest extent. It claims to be able to replace the F-16, F/A-18 and other four-generation aircraft models, and its powerful performance attracts multinational armies to compete for procurement.
Compared with the fourth-generation aircraft, the technical performance of the fifth-generation aircraft has achieved a huge leap forward.
It is reported that this kind of spanning even far exceeds the generation gap between the previous four generations of fighters.
This is due to the application of a large number of "black technologies" such as the stealth shape of the fifth-generation aircraft, active phased array radar and advanced modular avionics systems.
There is no doubt that the installation of the fifth-generation aircraft can bring a qualitative leap to the combat effectiveness of the Air Force.
However, after the installation of the F-35 fighter jets, many failures and problems followed, which plagued the installation of the national army.
It turned out that when the F-35 fighter was developed, a number of fatal flaws and nearly a thousand safety problems were exposed.
Affected by different environmental and climatic factors around the world, the F-35 suffered serious "acclimatization" - the frequent peeling of the coating and the low temperature damage of the battery, which caused headaches for maintenance personnel.
Not only that, complex systems bring multiple challenges to safeguarding.
As we all know, the fifth-generation aircraft integrates many advanced technologies on the same platform, and compatibility problems will inevitably occur. Just like the new system needs to be run in, there are many unforeseen problems in the early flight of the fighter, which affect the flight reliability of the fighter.
Many problems have brought new challenges to the maintenance of the fifth-generation aircraft, and maintenance personnel in various countries have spent a lot of energy on this.
In the face of "innate" deficiencies, "acquired" modification has become a must-answer question.
So, what modifications and upgrades have foreign maintenance personnel made to the fifth-generation aircraft?
One is to build a strong "brain".
F-35 integrated processor (referred to as ICP) is known as the "fighter brain", with powerful data processing capabilities, the processing speed is 10 times that of the F-22, and a series of data processing such as aircraft communication, guidance and control must rely on ICP is functioning normally.
The F-35 fighter has more than 8 million lines of various program codes, 5 times that of the F-22, but has more than 900 software defects. A series of problems forced the R&D and maintenance personnel to frequently upgrade and repair the system.
We know that after the smartphone is upgraded with new software, the system performance will slow down.
The same is true for fighter jets. After several software upgrades, the ICP's ability to operate will also encounter bottlenecks.
Due to the complex modular design structure, the repair and upgrade of the ICP can only be solved by replacing the module.
According to sources, the upgraded processor is expected to enter production in 2023.
The second is to improve "vision".
The F-35 fighter helmet has a series of technological means such as night vision system, forward-looking infrared tracking system, and virtual head-up display.
Before being put into use, it is necessary to scan the head and build a model to meet the pilot's "private customization".
However, shortly after use, some helmets had a "green light" problem.
Some foreign pilots said that when flying at night in bad weather, the helmet night vision camera will display green stripes.
Just as the eyeballs are hard to see objects in the dark after being irradiated by strong light, the green light will make the pupils constrict, so that the pilot cannot see the light outside the aircraft, causing a safety hazard.
At present, software upgrades, replacement of organic light-emitting diodes and other means have been applied to the modification and upgrade of helmets, and the problem of "green light" has also been temporarily improved.
The third is to cure "hypoxia".
The importance of the fighter oxygen supply system is self-evident. The oxygen supply system of the F-35 fighter can directly absorb and convert oxygen from the atmosphere, changing the traditional oxygen supply method of carrying oxygen from the ground.
However, after the backup oxygen supply is cancelled, once the main oxygen supply system fails, it is very easy to cause the pilot to suffer from hypoxia.
Since its service, F-35 fighter pilots have reported dozens of hypoxia problems, which once grounded the fighter and even caused flight accidents.
After the modification, the backup oxygen system is re-installed on the F-35 fighter. When the main oxygen supply system fails, the backup system can be automatically activated to prevent the pilot from losing consciousness due to lack of oxygen and causing the fighter to lose control.
The onboard oxygen supply system of the F-35 is also equipped with an automatic seat backup oxygen source. In an emergency, after the pilot is ejected from the fighter, the backup system automatically works to solve the problem of oxygen supply.
With the continuous efforts of aviation designers, the design flaws of the F-35 fighter are gradually being resolved.
Currently, one class of defects has been reduced from 15 to 7, and the overall performance has been well optimized.
Learn "Medicine" -
Specialized classes and schools to train "fighter doctors"
As "fighter doctors", the "medical skills" of maintenance personnel determine whether the fighter plane can be repaired quickly and effectively.
Taking the F-35 as an example, it is not easy to repair it, involving 15 majors such as ground support and avionics equipment, requiring maintenance personnel to master multiple disciplines.
Some people ask that the repair base has trained a large number of maintenance technicians. Can the maintenance experience of the old model be "grafted" to the new model?
Due to the complex structure and precise components of the fifth-generation machine, after the maintenance personnel of the old model undertake the maintenance task of the fifth-generation machine, except for the repair experience of a few common parts, which can be directly used for reference, most maintenance techniques must be relearned, resulting in a shortage of maintenance personnel. .
Maintenance talents have become "just in need".
Relevant countries have begun to devote themselves to the construction of maintenance training systems and establish maintenance training schools to improve the professional skills of maintenance personnel.
The first is "hardware" preparation and upgrading of necessary teaching aids and resources.
Compared with previous generations of fighters, the maintenance of fifth-generation aircraft is more specialized and intelligent.
According to the maintenance procedures and characteristics of the fifth-generation aircraft, the school sets up maintenance training devices, produces multimedia courses, and formulates training plans to meet daily training needs.
The second is to upgrade the "software" and introduce advanced training systems.
Unlike on-site, hands-on "big class" training, the new training system uses mission drills and desktop simulators, providing a 360-degree viewing angle and a desktop interface that is synchronized with the aircraft display.
Students don't even need to touch the aircraft, they can understand most of the maintenance procedures and fault characteristics, and complete more than 95% of the training content.
The third is the development of "curriculum" and the construction of a professional training system.
Professional maintenance training courses are essential, including basic theoretical knowledge of aircraft maintenance, professional knowledge of airframe structure, airborne electronic systems, as well as courses such as the use of electronic technical manuals and interactive software operations.
After completing all courses, students must pass a series of assessments and assessments in order to successfully receive the diploma.
Under the professional maintenance training mode, more than 2,000 maintenance technicians from relevant countries can complete their graduation every year, providing guarantee for the maintenance of fifth-generation machines.
Shorten the cycle -
From simple to complex and from complex to simple
In modern air combat, whether fighters can achieve accurate and rapid maintenance is related to the building of the combat effectiveness of the Air Force's equipment.
As early as the early 1920s, the maintenance system was born with the start of aviation technology, forming a repair shop-style first-level maintenance system.
After decades of development, the maintenance system has undergone an evolution from simple to complex, and then from complex to simple. Relay-level and base-level maintenance are widely used in the field of fighter maintenance.
With the change of combat training needs and maintenance concepts, the fifth-generation aircraft got rid of the traditional three-level maintenance system, cancelled the intermediate-level maintenance, and adopted a high-efficiency and economical two-level maintenance system, which greatly shortened the fighter maintenance cycle.
However, although the secondary maintenance system has reduced maintenance links, there is still a "gap" between maintenance efficiency and combat training needs.
To this end, some foreign military enterprises have carried out a series of explorations.
First, improve base-level maintenance capabilities.
Some countries have made the construction of base-level maintenance capabilities the primary task of fighter aircraft repair. After systematic evaluation of maintenance capabilities, they have increased the spare parts reserves of maintenance bases and established maintenance bases with more complete facilities to ease the support pressure on fifth-generation aircraft.
Second, establish a global supply system for spare parts.
The United States plans to build a global supply network for the F-35 fighter jets. Through more than 100 routes, spare parts will be transported between countries where fifth-generation aircraft are installed, so as to reduce the waiting period for spare parts and improve maintenance efficiency.
Third, explore advanced maintenance methods.
After decades of exploration by aerospace engineers, the maintenance method based on condition monitoring has emerged, and the maintenance method is changing from predictive to preventive.
The new maintenance method can realize the monitoring and prediction of fighter status. When the repair work is not carried out, the maintenance work plan is generated in advance, and the fault scope is accurately narrowed, and the maintenance cost and workload are reduced.
Even if maintenance is difficult, the fifth-generation aircraft is still the development trend of future fighter aircraft.
The research and development work dedicated to upgrading maintenance capabilities has never stopped. Advanced technologies such as 3D printing, big data, and cloud computing have been continuously invested in the repair and maintenance of the fifth-generation aircraft, which not only enriches the "toolbox" for fighter aircraft maintenance, but also provides a new generation of fighter aircraft. Design and manufacture reserve "data" and draw "blueprint".