14 CFR · Part 27
14 CFR § 27.1435
Hydraulic systems.
(a)
Design. Each hydraulic system and its elements must withstand, without yielding, any structural loads expected in addition to hydraulic loads.
(b)
Tests. Each system must be substantiated by proof pressure tests. When proof tested, no part of any system may fail, malfunction, or experience a permanent set. The proof load of each system must be at least 1.5 times the maximum operating pressure of that system.
(c)
Accumulators. No hydraulic accumulator or pressurized reservoir may be installed on the engine side of any firewall unless it is an integral part of an engine.
Reflects the eCFR edition current as of September 29, 2026. Retrieved from ecfr.gov on October 16, 2026.
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