BC

• back course

  General

• beginning climb

  ATC

• British Columbia

  Weather

• patches

  METAR

BC has 4 meanings; the right one depends on context. A weather report, a NOTAM or an ATC clearance. Got a NOTAM full of contractions? Paste it into the decoder.

Source: FAA Order JO 7340.2 Contractions. Not for operational use.