7.  Attitude indicator: Uncaged, if applicable. If electronic  flight instrumentation is installed, check emergency  system to include its battery as appropriate. 8.  Altimeter: Set the current altimeter setting and ensure  that the pointers indicate the elevation of the airport. 9.  VSI: Zero indication, as applicable (if electronic flight  instrumentation is installed). 10. Heading indicator: Uncaged, if applicable. 11. Turn coordinator: If applicable, miniature aircraft  level, ball approximately centered (level terrain).  12. Magnetic compass: Full of fluid and the correction  card is in place and current. 13. Clock: Set to the correct time and running. 14. Engine instruments: Proper markings and readings,  as applicable if electronic flight instrumentation is  installed. 15. Deicing and anti-icing equipment: Check availability  and fluid quantity. 16. Alternate static-source valve: Be sure it can be opened  if needed, and that it is fully closed. 17. Pitot tube heater: Check by watching the ammeter  when it is turned on, or by using the method specified  in the POH/AFM. 1.  When the master switch is turned on, listen to the  gyros as they spin up. Any hesitation or unusual noises  should be investigated before flight. 2.  Suction gauge or electrical indicators: Check the  source of power for the gyro instruments. The suction  developed should be appropriate for the instruments  in that particular aircraft. If the gyros are electrically  driven, check the generators and inverters for proper  operation. 3.  Magnetic compass: Check the card for freedom of  movement and confirm the bowl is full of fluid.  Determine compass accuracy by comparing the  indicated heading against a known heading (runway  heading) while the airplane is stopped or taxiing  straight. Remote indicating compasses should also be  checked against known headings. Note the compass  card correction for the takeoff runway heading. 4.  Heading indicator: Allow 5 minutes after starting  engines for the gyro to spin up. Before taxiing, or  while taxiing straight, set the heading indicator to  correspond with the magnetic compass heading. A  slaved gyrocompass should be checked for slaving  action and its indications compared with those of the  1.  Turn coordinator: During taxi turns, check the  miniature aircraft for proper turn indications. The ball  or slip/skid should move freely. The ball or slip/skid  indicator should move opposite to the direction of  turns. The turn instrument should indicate the direction  of the turn. While taxiing straight, the miniature  aircraft (as appropriate) should be level. 5.  Attitude indicator: Allow the same time as noted  above for gyros to spin up. If the horizon bar erects  to the horizontal position and remains at the correct  position for the attitude of the airplane, or if it begins  to vibrate after this attitude is reached and then slowly  stops vibrating altogether, the instrument is operating  properly. If an electronic flight instrument system  is installed, consult the flight manual for proper  procedures. 6.  Altimeter: With the altimeter set to the current reported  altimeter setting, note any variation between the  known field elevation and the altimeter indication. If  the indication is not within 75 feet of field elevation,  the accuracy of the altimeter is questionable and  the problem should be referred to a repair station  for evaluation and possible correction. Because the  elevation of the ramp or hangar area might differ  significantly from field elevation, recheck when in  the run-up area if the error exceeds 75 feet. When  no altimeter setting is available, set the altimeter  to the published field elevation during the preflight  instrument check. 7.  VSI: The instrument should read zero. If it does not,  tap the panel gently. If an electronic flight instrument  system is installed, consult the flight manual for proper  procedures. 8.  Engine instruments: Check for proper readings.  9.  Radio equipment: Check for proper operation and set  as desired. 10. Deicing and anti-icing equipment: Check operation. Ensuring the functionality of the turn coordinator, heading  indicator, magnetic compass, and attitude indicator prior  to taxiing and takeoff is essential to flight safety. Runway  incursion is an incident at an airport that adversely affects  runway safety and pilots must mitigate this risk by ensuring  that all of the directional flight instruments are checked  properly before taxiing or taking off so that the position  of the aircraft in relation to the runway and other traffic is  always known.  Taxiing and Takeoff After Engine Start magnetic compass. If an electronic flight instrument  system is installed, consult the flight manual for proper  procedures. 5-37