Instrument Cockpit Check

Before blasting off into "the soup," one should perform an instrument cockpit check to make sure that all instruments are functioning correctly and reading accurately.  It would be a much better situation to catch a problem while on the ground instead of in solid IMC.  The latter would make for a very stressful flight, and would probably give you a few more grey hairs if you ended up making it back at all.

Flight Instruments: Attitude Indicator (left) and Altimeter (right)

But that is why we perform checks for the most vital instruments to make sure everything is functioning 100% before entering solid IMC.  Here are the steps you should take before every instrument flight.

1. While stationary, make sure the Airspeed Indicator reads 0.  Having an ASI that displays otherwise is a good indication that the pitot tube is malfunctioning.  This would be an excellent time to turn around and evaluate the problem.
2. Make sure the Attitude Indicator is upright, erect, and stable (no more than 5 degrees of bank while turning on the ground after a 3 minute period).  A lazy Attitude Indicator could signify either a bad gyro or a weak vacuum system.  Either option does not bode well for instrument flying.
3. Verify that the Altimeter is within 75 ft of field elevation.  IFR flying relies heavily on maintaining prescribed altitudes by ATC.  If your Altimeter is off, your altitude is going to be off, and ATC will be none to happy with you.  
4. Check the Turn Coordinator. The airplane should bank into the turn, and the ball should swing to the outside of the turn.  This will help make sure those standard rate turns are actually standard rate.
5. Verify the DG matches the Compass and turns in the correct direction.  This just ensures that the gyro in the DG is functioning properly.  It would also be wise to check the amount of procession of the DG between startup and runup.  If the gyro is processing too much, it might be better to hold off on that flight.
6. Check that the VSI shows 0.  On the ground your static pressure should not be changing, therefore your VSI should show zero.  An indication otherwise may suggest a malfunctioning static source.
7. Verify that the Compass is floating freely, full of fluid, and that the compass card is present and readable.  This is just a backup for when that DG decides to fail.
8. VOR receiver check conducted within last 30 days.  It is under Federal Regulations that you must have done a VOR recover check within 30 days of the flight.  Making sure the test is within date will make sure you are legal and will keep you safe.  I will post an article dedicated to explain VOR checks.
9. Make sure the Clock is set to current time and is not frozen.  That would be unfortunate right?  Getting a holding clearance and not being able to time your hold.  Or worse, having to use time to determine your MAP and not noticing the clock is frozen.  Save yourself the trouble and just check this before every flight.

Always be sure to take all the necessary preflight action, and be safe out there!