In what situations does it make sense to measure absolute pressure and what situations does it make sense to measure gauge pressure?
At the heart of this question, your interviewer will first be looking to hear that you understand the basic concepts of the differences between measuring absolute pressure and gauge pressure. After you explain the difference, make sure to talk about specific applications of each pressure measurement in Aerospace Engineering and explain why that specific measurement is used in that application.
"Because gauge pressure measures is directly influenced by changes in atmospheric pressure, it is best used in measurements where a tight seal is not creating a vacuum effect. One of the most common gauge pressure measurements on an aircraft is in the tire pressure because atmospheric pressure has a direct effect on that measurement. On the other hand, absolute pressure measures pressure in a true vacuum situation with a tight seal. This is most often used to measure amounts of fuel in a sealed tank. There are also situations where a differential pressure gauge is used to detect the difference between these two pressures and an airspeed indicator is a very common gauge for this."
