B737Theory - APU backpressure. Here a question out of the field of operation related to APU bleed use in flight. Flying with some colleagues, we were studying (y) a couple scenarios relating
![Figure 1 from Spectral Signatures of Pneumatic Actuator Failures: Closed-Loop Approach | Semantic Scholar Figure 1 from Spectral Signatures of Pneumatic Actuator Failures: Closed-Loop Approach | Semantic Scholar](https://d3i71xaburhd42.cloudfront.net/45870085d3adb6a6b8120a5a64acb84951b9721a/2-Figure1-1.png)
Figure 1 from Spectral Signatures of Pneumatic Actuator Failures: Closed-Loop Approach | Semantic Scholar
Pressure Regulated Shutoff Valves (PRSOV) in the Environmental Control... | Download Scientific Diagram
![A mimicking technique of back pressure in the hardware-in-the-loop simulation of a fuel control unit - Yuan Yuan, Zhiwen Zhao, Tianhong Zhang, 2020 A mimicking technique of back pressure in the hardware-in-the-loop simulation of a fuel control unit - Yuan Yuan, Zhiwen Zhao, Tianhong Zhang, 2020](https://journals.sagepub.com/cms/10.1177/0037549719873969/asset/images/large/10.1177_0037549719873969-fig1.jpeg)
A mimicking technique of back pressure in the hardware-in-the-loop simulation of a fuel control unit - Yuan Yuan, Zhiwen Zhao, Tianhong Zhang, 2020
![Diagram of a pressure regulator valve PRSOV Adapted from Turcio (2014). | Download Scientific Diagram Diagram of a pressure regulator valve PRSOV Adapted from Turcio (2014). | Download Scientific Diagram](https://www.researchgate.net/publication/282176375/figure/fig1/AS:771710693421056@1561001575036/Diagram-of-a-pressure-regulator-valve-PRSOV-Adapted-from-Turcio-2014.jpg)
Diagram of a pressure regulator valve PRSOV Adapted from Turcio (2014). | Download Scientific Diagram
![A mimicking technique of back pressure in the hardware-in-the-loop simulation of a fuel control unit - Yuan Yuan, Zhiwen Zhao, Tianhong Zhang, 2020 A mimicking technique of back pressure in the hardware-in-the-loop simulation of a fuel control unit - Yuan Yuan, Zhiwen Zhao, Tianhong Zhang, 2020](https://journals.sagepub.com/cms/10.1177/0037549719873969/asset/images/large/10.1177_0037549719873969-fig2.jpeg)