From: utzoo!watmath!watcgl!dmmartindale Newsgroups: net.aviation Title: Re: Losing vacuum pump in IFR Article-I.D.: watcgl.93 Posted: Tue Jan 4 11:22:35 1983 Received: Wed Jan 5 00:23:35 1983 References: ihuxa.170 A backup vacuum pump has at least two advantages over a backup electric attitude indicator - your directional gyro stays working too, and you don't have to figure out where to put the extra attitude indicator. It would have to be somewhere you can see it reasonably well, and panel space tends to be pretty tight on the smaller 4-seaters when equipped for IFR.