The first thing you do is zip on down to the pharmacy or medical supply house and buy one of those rubber air bulbs you commonly see used with blood pressure cuffs. (There are other types as well.) VWR Scientific, which has outlets in 20 states and several foreign countries, will sell you a suction bulb by mail Call the SFO office at 415-467-4100 or the PIA office at 412/782-4230 (or look in your phone book) and tell them you want a Baumanometer bulb, Cat. No. 14605-350 ($8.50). You’ll also need a short length of thick-walled tubing (such as Tygon-type or surgical tubing) and a hose clamp, obtainable at any auto or motorcycle parts store. A jar of petroleum jelly wouldn’t be a bad idea either. Also, depending on where your plane’s static port is, you may need an assistant to help out in the cockpit.

Before beginning the static test, go inside the cockpit and ensure that the “alternate static source” valve is off; if your plane has a static-system drain, drain the system.  If your plane has two interconnected static ports (one one each side of the fuselage—a common arrangement for counteracting the effects of sideslipping), carefully seal off one port with tape. This seal must be air-tight, but use care not to foul the port with dirt or gum. Couple the short piece of surgical tubing to the Baumanometer bulb securely using a a hose clamp, and apply a small amount of petroleum jelly to the open end of the hose (which should be cut off very squarely so that it will mate flatly to the side of the airplane). The idea is to stick the hose over the static port (holding it there with firm hand pressure) to make a temporary air-tight seal, then pump the suction bulb to create a partial vacuum in the airplane static system. While you’re doing this, somebody—preferably you—must watch the airplane’s airspeed indicator, altimeter, and VS/rate-of-climb indicator. Continue squeezing the Baumanometer bulb until an indicated altitude of 1,000 to 2,000 feet (AGL) is shown, but monitor the ASI and VSI to prevent suction “spikes” that could damage those instruments. (In no case do you want to exceed the travel limits of the airspeed or ROC indicators.)

Once the altimeter is showing a couple grand, stop pumping and hold fast on the suction. There should be no leaks, and the VSI should hold steady at or close to zero.  Cessna’s shop manuals allow a rate of leakage of 100 fpm (measured by the altimeter and a stopwatch). Anything more that that suggests a bad hose clamp or leaky instrument somewhere in the system. (Troubleshooting this situation is fairly easy—all you do is disconnect the common static lines from the VSI, altimeter, and ASI, and reconnect the altimeter into the static system, Then repeat the leakdown test as necessary to identify the faulty gage. Alternatively, with the VSI, ASI, and autopilot plumbing capped off and isolated from the static system, apply pressure to the static system until the altimeter "descends” 500 feet or more, then paint suspect hose connections with soap fluid to find the leaker.) At the end of the test, admit air back into the system slowly, so as not to damage delicate instrument mechanisms.

Sounds pretty easy, and it is. Just remember that any time any static-system connection is broken—for any reason—the basic static check must be repeated and entered in the plane’s logs (read FAR 91.171). Also remember that for IFR flight, a separate altimeter check must be done—by an approved instrument shop, not an A&P. The static check, however, is one check any A&P can do legally—which also means you can do it legally, with a signoff.