Recently the Transportation Safety Board of Canada released a report for a crash in November 2011 near Fort St. John airport, British Columbia. The accident was listed as Controlled Flight Into Terrain (CFIT) of the Cessna 185E, and the lone occupant died.
Among other factors contributing to the crash, including black hole effect, it was identified that the pilot had used his cell phone for voice calls totaling 28 minutes, and text messages. Although the pilot did not use his cell phone for the 11 minutes prior to the crash for communication, the aircraft was seen on radar to have large altitude deviations during cell phone calls.
Although the TSB has not completed a study of cell phone usage and distraction of pilots, the Canadian Council of Motor Transport Administrators describes distracted drivers as:
Distracted driving is the diversion of attention from driving, as a result of the driver focusing on a non–driving object, activity, event or person. This diversion reduces awareness, decision–making or performance leading to increased risk of driver error, near–crashes or crashes. The diversion of attention is not attributed to a medical condition, alcohol/drug use and/or fatigue.”
See the TSB report here: http://www.tsb.gc.ca/eng/rapports-reports/aviation/2011/a11w0180/a11w0180.asp