Radio transmissions released by the Federal Aviation Administration show snippets of the frantic rescue efforts that unfolded after a floatplane crashed in Alaska, killing former U.S. Sen. Ted Stevens and four others.

At one point, a pilot surveying the wreckage urged an FAA flight operator to get a rescue helicopter to the crash site "immediately, immediately, fast." Another pilot said survivors would be exceedingly difficult to reach by foot.

The three hours of recorded transmissions were obtained by The Associated Press through a records request regarding the Aug. 9 crash north of Dillingham.

Conversations were redacted in some places, so there are gaps in the chain of events that culminated in the rescue of four survivors, including former NASA chief Sean O'Keefe and his 19-year-old son, Kevin O'Keefe.