Selkirk College IATPL Program Manual
Beech 95 POH Effective September 1, 2005 Appendix 14 - 82
Vacuum System
The D95A (GSAK) is equipped with two engine-driven vacuum pumps.
The E95 (FXFG) is equipped with two engine-driven pressure pumps.
These provide suction or pressure for the gyros in the attitude indicator and standby
heading indicator (on the engine instrument panel.) A gauge on the engine instrument
panel indicates the amount of suction/pressure provided as well as confirming that both
pumps are functional. Operationally the suction and pressure systems work the same. In
both systems one pump is adequate to power the instruments should the other pump fail.
Check valves prevent loss of pressure if one pump fails.
The diagram above shows the vacuum system in TD638 (GSAK.) Note that the vacuum
gauge shows the amount of suction inside the case of the attitude indicator. The standby
heading indicator has its own vacuum line that is not connected to the gauge. Note also
that air passes through a filter before entering both the attitude indicator and the heading
indicator. A plugged filter will render either instrument inoperative. In this system the
outflow air is “dumped” in the engine compartment, at the vacuum pump.
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