A private group of Swiss pilots has founded an NGO to search for migrants' boats in distress in the Mediterranean. (SRF/swissinfo.ch)
The volunteers from the Humanitarian Pilots Initiative claim its easier to spot small boats from the air than it is from the bridge of a ship, and that planes can cover a much wider area more quickly.
The main search zone is just off the Libyan coast. Ships here from the European Union force known as Operation Sophia patrol the seas in an effort to put a stop to migrant smuggling or human trafficking. But there are also civilian rescue ships.
Every migrant boat spotted by the Swiss pilots is immediately report to the sea emergency rescue authorities in Rome. After the people on the boats are secured, they are handed over to the Italian coastguard.