***Link*** :: [§ 91.171 VOR equipment check for IFR operations.](https://www.ecfr.gov/current/title-14/section-91.171) ***Description*** :: `= this.link` ***Related To***: [[AAV1ATE]] ***Author*** :: [[FAA]] #### Key Quotes * No person may operate a civil aircraft under [[IFR]] using the [[VOR]] system... unless... Has been operationally checked within the preceding 30 days, and was found to be within the limits of the permissible * each person conducting a VOR check * a test signal... plus or minus 4 degrees * point on the airport surface designated as a VOR system checkpoint by the Administrator... plus or minus 4 degrees * airborne checkpoint designated by the Administrator... plus or minus 6 degrees * If no check signal or point is available, while in flight— * established VOR airway... prominent ground point along the selected radial preferably more than 20 nautical miles from the VOR... over the ground point... 6 degrees * dual system VOR... Both systems shall be tuned to the same VOR ground facility and note the indicated bearings to that station.... 4 degrees * Each person making the VOR operational check... shall enter the date, place, bearing error, and sign the aircraft log or other record. #source #far