In S1E19 "Deus Ex Machina", Locke and Boone discover a Beechcraft plane perched in the canopy of the jungle. Locke had dreamt of the plane after asking for a sign relating to how to open the hatch he and Boone had discovered. Because Locke's leg had been injured earlier while trying to open the hatch, and it appearing that he was once again beginning to lose the use of his legs, Boone climbed up into the plane to investigate it.
Once inside the plane, Boone discovered maps and heroin-filled Virgin Mary statues and realized it had been used as a drug smuggling plane. In the plane's cockpit, Boone finds a radio and checks to see if it is functional. When he heard static, Boone sends out his a transmission, "Hello? Hello? Anybody out there? Mayday, mayday."
A voice responded to Boone over the radio, saying "Is someone out there?" Boone excitedly answers, "Hello. Hello. Can you hear me?" The mysterious voice on the radio replied, "Repeat your transmission please."
As the plane began to shift in the trees from Boone's weight, Boone sent out his final transmission, "Hello. We're survivors of the crash of Oceanic flight 815, please copy", to which the voice on the radio replied, "Hello. We're the survivors of Oceanic flight 815." At that point, the plane falls out of the trees and flips over, leaving Boone with injuries that ultimately led to his death.
The mystery of the voice on the radio, and exactly what that final transmission was, remained until S2E7 "The Other 48 Days", which chronicled the plight of the tail end survivors of Oceanic flight 815 during their first 48 days on the island.
After 9 of the tailies had apparently been kidnapped by the Others, the remaining survivors, Ana-Lucia, Goodwin, Nathan, Eko, Bernard, Libby and Cindy, set out into the jungle in search of a safer place to set up their camp. After several suspicious trips into the jungle, Ana Lucia begins to suspect that Nathan is in fact an 'Other'. Nathan is later imprisoned by her in a pit she has constructed as a holding cell. Goodwin, the actual 'Other', helps Nathan out of his prison and under the pretense of helping him escape, kills Nathan by breaking his neck. When it is discovered by the survivors that Nathan was missing, they delve deeper into the jungle and found a bunker-type structure that we know now as the Dharma Arrow Station. Inside the bunker, the tailies find a locker, containing various items including a glass eye, blankets, a Bible, and a radio.
Bernard attempts to use the radio to send a distress signal, but can't get a signal. Goodwin suggests taking the radio up to a higher elevation in the hills to get better reception, and Ana-Lucia accompanies him. Ana-Lucia figures out that Goodwin is in fact the Other who has infiltrated their group. After a fierce struggle, Ana Lucia impales Goodwin, and kills him.
Several days later, Bernard again tries the radio, explaining that he only turns it on for a few minutes a day. The tailies hear Boone's mayday call and Bernard answers him, saying "Hello. We're the survivors of Oceanic flight 815." Ana-Lucia takes the radio from Bernard and turns it off, thinking that the voice calling out to them is one of the Others trying to draw them out of their hiding place.
