The AS-355 helicopter belonging to Balt Avia crashed around 6:30 p.m. (1430 GMT) Saturday about 75 kilometers (45 miles) west of St. Petersburg, Russia, on the shores of the Gulf of Finland.
A crew member and two passengers were injured and rescuers were searching for the lost pilot. One passenger was unharmed.
The officials said the cause of the crash was being investigated.