Recently, CAAC issued a Chinese Technical Standard Order Authorization (CTSOA) to SINOPEC AEH I, a domestically developed fire-resistant aviation phosphate ester hydraulic oil by China Petroleum & Chemical Corporation (Sinopec). This marks the first airworthiness certification for a Chinese-made aviation hydraulic oil product, laying the foundation for its commercial application in civil aviation. More importantly, it marks China's breakthrough in the aviation hydraulic oil sector, making it the third country with the capability to produce fire-resistant aviation phosphate ester hydraulic oil in the world.
Aviation hydraulic oil serves as the medium for energy transmission in aircraft hydraulic systems while also performing critical functions such as lubrication and heat conduction. Its performance will have a significant impact on aircraft operational safety. The development of aviation hydraulic oil in China faces not only high technical barriers but also long-term monopolization of airworthiness validation technologies by foreign institutions.
Since 2019, CAAC has been advancing the capacity-building for airworthiness certification of aviation hydraulic oil. Fuel & Chemical Airworthiness Certification Center of CAAC (FCCC) established a validation platform domestically developed for airworthiness certification. CAAC also decided to regulate hydraulic oils through the formulation and issuance of the Chinese Technical Standard Order (CTSO). On December 24, 2020, CAAC issued a technical standard order Fire-Resistant Aviation Phosphate Ester Hydraulic Oil (CTSO-2C706), laying the foundation for independent airworthiness certification of hydraulic oil.
On March 15, 2021, Sinopec submitted an airworthiness certification application for its SINOPEC AEH I hydraulic oil to CAAC. CAAC approved the application and entrusted FCCC to conduct the technical review. FCCC assembled a team of experts to rigorously evaluate the products in compliance with airworthiness regulations, covering technical documentation, formulation processes, manufacturing conformity inspections, testing capabilities, quality systems, and product performance. Multiple batches of samples underwent physical-chemical tests, application performance test as well as bench tests. The results confirmed that all technical indicators of the domestic hydraulic oil have successfully met regulatory standards. CAAC subsequently issued the CTSOA.
A representative from FCCC indicated that the airworthiness approval towards China's independently developed hydraulic oil is a significant achievement in civil aviation's commitment to technological innovation, self-reliance, and domestic substitution. It also exemplifies the collaborative integration of airworthiness certification and industrial development, driving continuous advancements in the fields of technical capabilities and product quality.
