Wreckage has already washed up on shore
A search is underway after a light aircraft crashed into the sea off the English coast.
The plane is understood to have gone into about half a mile from a beach in East Sussex.
It was initially thought that up to four people were on board, but authorities now say they believe the pilot was the only person on the aircraft.
The plane is thought to have ditched just after 5pm. Wreckage has already washed up on shore and police have appealed for witnesses to come forward.
Two coastguard helicopters and the two lifeboat crews are attending.
A Coastguard spokeswoman said: "UK Coastguard coordinated a search for a light aircraft which ditched into the sea half a mile from Rye Harbour in East Sussex.
"The alarm was raised at 5.05pm and reports indicated one person was on board the aircraft.
"The aircraft and pilot have not been found and the current search is likely to continue until dusk."
A statement from the RNLI said: "Rye Harbour and Dungeness RNLI lifeboats were requested to launch this afternoon by HM Coastguard following reports of a light aircraft which ditched into the sea off Rye Harbour. Reports indicated there was one person on board.
"Rye Harbour RNLI's inshore lifeboat launched at 5.23pm and Dungeness RNLI's all-weather lifeboat launched around five minutes later.
"Both lifeboats and their volunteer crews are conducting searches about three-quarters-of a mile offshore between Winchelsea beach and Pett Level beach.
"Also involved in the incident are Rye Harbour and Dungeness Coastguard Rescue Teams and two Coastguard Search and Rescue helicopters."
A Sussex Police spokesman said: "Initial reports suggest that the aircraft comes from a local Aero Club and that the man flying it was the sole occupant.
"Some wreckage which is believed to be from aircraft has been found washed ashore at Winchelsea Beach."
The Air Accident Investigation Branch will be carrying out an investigation.