Why wastegate actuators are the root of many airplane engine problems

Aircraft are made up of tens of thousands of individual components, and the smallest pieces can have large impacts. One of these small but critical components is the wastegate actuator, which works within the turbocharging system to direct exhaust gas in the right direction. Its failure rapidly escalates to system-level flight safety concerns, leading to over-pressurization, rejected takeoff attempts, or even a loss of engine power and system shutdown.

Wastegate actuator-related events are shockingly frequent. They account for about 30% of engine problems, and data from one specific low-altitude Diamond aircraft fleet — the DA42NG, which uses the Austro Engine AE300 engine — showed its average lifetime, about 729 flight hours, falls far short of its 1,800-hour target. Li et al. sought to answer why.

The researchers analyzed an AE300 that degraded and failed after about 500 flight hours and used their insights to create a model to further study the standard failure mechanisms. They found a control rod that adjusts the wastegate opening is the primary culprit for premature mechanical failures, its deflection leading to highly localized stress and abrasion.

“A seemingly minor control rod misalignment, undetectable in routine checks, created a critical stress concentration at the diaphragm’s inner sidewall,” said author Deqiang Tan.

Undetectable with standard visual inspections, this single factor is the primary cause of rapidly-escalating failures.

The good news is this is directly actionable, and the authors’ proactive blueprint prevents hidden risks. Although they studied one particular engine, the findings are applicable to a wide range of similar actuator designs.

“This reinforces the need for deeper, science-driven investigation into seemingly mundane components, especially as aviation systems grow more complex,” said Tan. “It’s a compelling case for how targeted research can directly enhance safety, inform design, and shape maintenance protocols worldwide.”

Source: “Contact-induced premature failure of a fabric-reinforced fluorosilicone diaphragm in an AE300 wastegate actuator,” by Rui Li, Junxiang Chen, Li Zhang, Deqiang Tan, Yue Hu, Ke Zhen, Xin Dai, and Longwen Zhang, AIP Advances (2025). The article can be accessed at https://doi.org/10.1063/5.0306728 .