On January 23, 2015, I flew from Buenos Aires, Argentina (EZE) to Santiago, Chile (SCL). It was a very comfortable night flight in a Boeing 787 Dreamliner of LAN airlines, though it was delayed.
During the descent and a pronounced turn to the left at approximately 4,000ft above the Andes Mountains, I saw through the window a wood fire in the middle of darkness with some shadows around. Then a brilliant white light blinking: three short flashes, three long flashes, three short flashes. I thought: Wow! That antenna blinked like an SOS signal!
One second after the first sequence, again: three short, three long, three short. Then I unfastened the security belt to run and tell the closest flight attendant: Sir, there is an SOS signal there! He started to give attention to it.
After a successful landing on runway 17 L/R, I asked the flight attendant if they have a procedure to handle this kind of sightings. He told me there is no such procedure and that I should go to inform the civil protection office.
Due to a lack of enough time before the next flight, I asked a security officer to inform the civil protection office, giving her the flight number, exact time of the sighting and after calling the person in charge, she asked me for my name and details about the sighting. Trying to be descriptive, I clearly told her all details before running to catch the next flight and almost losing it.
On next day I tried to contact the civil protection office and googled for news about alpinists in chile finding nothing relevant even after one month. Good news are that the place is relatively close to the civilization (around 8 km) and that the mountains are lower than the ones in the east (about 6,000ft). If there were people in danger, they would probably have found the way to be safe and receive help.
There was a kid of around 11 years old sitting on the window. Both saw the same light, only that he behaved indifferent, probably due to ignorance of the SOS morse code distress signal.
Passengers and crew members could save lives relaying mayday calls and responding to potentially life threatening situations :D
The place of sighting was somewhere over the mountains in the west of Los Andes in Chile.