On August 3, 2006, at 1415 Pacific daylight time a Cessna 172M, N12626, impacted terrain and a ditch during takeoff from runway 13 at the Calaveras County Airport (CPU) near San Andreas, California. The certificated flight instructor (CFI), the dual student, and a passenger were not injured. The airplane sustained substantial damage. The airplane was registered to a company doing business as (d.b.a.) TDL Aero Enterprises, Merced, California. The instructional flight was conducted under the provisions of 14 CFR Part 91. Visual meteorological conditions prevailed, and a flight plan had not been filed for the local training flight, which originated about 15 minutes prior to the accident. According to the CFI, he was providing instruction for the student pilot who was preparing for his private pilot check ride. They flew from Merced and landed at Calaveras County and conducted a couple of takeoffs and landings. They were in the process of practicing a soft-field takeoff when the accident occurred. The CFI's account of the sequence revealed that the student conducted the soft-field takeoff with the airplane established in a nose high pitch attitude. The CFI said that the airplane very quickly rose above ground effect and the student was a little slow in lowering the nose of the airplane to gain airspeed. The instructor said he delayed taking corrective action since the student's check ride was coming up and he wanted to see the student take action on his own. The flight continued and the student informed the CFI that it felt as though the right wing wanted to drop. The CFI took control of the airplane, lowered the nose and applied left aileron, but it was too late. The left wing dropped and the airplane descended to ground impact.