At 22:10 AT (01:10 UTC, 52 minutes after takeoff), the flight crew detected an odor in the cockpit and determined it to be smoke from the air conditioning system. Four minutes later, the odor returned and smoke became visible, prompting the pilots to make a "pan-pan" radio call to Moncton air traffic control, the area control center (ACC) station in charge of air traffic over the Canadian province of Nova Scotia. The pan-pan call indicated that there was an urgency due to smoke in the cockpit but did not declare an emergency as denoted by a "mayday" call. The crew requested a diversion to Logan International Airport in Boston ( away) before accepting Moncton ATC's offer of radar vectors to the closer Halifax International Airport in Enfield, Nova Scotia, away.