Despite their increasing obsolescence, vacuum pumps remain installed aboard the vast majority of piston-powered aircraft, providing the energy to spin the gyroscopes in flight instruments like attitude indicators and directional gyros. Even newer aircraft sporting factory-installed “glass” panels may have a vacuum (or pressure) pump powering one or more backup instruments. Odds are, the airplane you fly has at least one, and the odds that it rarely gets serviced are even better.
A common theme in many of my previous articles for Aviation Safety is that aircraft systems require regular service and system component replacement at regular intervals, according to manufacturer specifications. This also is true for vacuum/pressure pumps, which can be impossible to inspect without disassembly, which typically can’t be done in the field. Perhaps more so than many other aircraft systems—except perhaps the powerplant(s)—ignoring this system until it fails could lead to catastrophe, or at least significant inconvenience and expense.
