Alaska PLB Program


Since 1994, the State of Alaska has been utilizing 406 MHz Personal Locator Beacons to help protect people from the hazards of the Arctic. Many people must live, work or travel through harsh, remote regions of the state where communications are extremely limited. Prior to the PLBprogram, most people in need of rescue had to rely on themselves. Needless to say, in such an unforgiving climate they often perished. The wilderness of Alaska has swallowed up many a traveller never to be heard from again. The PLB program is helping to put an end to this.

How It Works

When activated, an Alaska PLB transmits a digitally coded signal on the 406.025 MHz frequency. This signal is received by a COSPAS, SARSATor GOES satellite and relayed to a ground station. The ground station calculates the PLB location and transmits the information to the US Mission Control Center. The USMCC recognizes these specially coded beacons as Alaska PLBs and transmits a distress message directly to the Alaska Rescue Coordination Center (AKRCC) at Fort Richardsonjust north of Anchorage. The AKRCC then uses state, local or federal assetts to conduct the rescue.

Lets look at two fictitious scenarios...

1982 Scenario

A native hunter leaves Wainwright, AK enroute to thevillage of Atkusuk. He's traveling by snow mobile and the trip should take about 4 hours. He thoroughly prepares for the trip and is well equipped. A brief check of the weather reveals that a storm is due to hit later that night, well after his expected arrival. He leaves a trip plan with a friend and departs. Halfway there, his snow mobile hits a hidden crevasse and flips. He is tossed onto the rock hard ice and suffers a broken leg. The snow mobile has a bent skid and won't run. He gathers his supplies and assesses his situation. Unable to travel on his broken leg, he erects a makeshift shelter. He's on the treeless tundra so there is no wood for a fire. He does have a small camping stove and uses it for warmth. That night, the storm rolls in. White out conditions exist. Forty knot winds and below zero temperatures buffett the hunter. He is now overdue inAtkusuk and a search party is launched for him. Unfortunately, they are turned back by the storm. During the short daylight period of the next day they search for him unsuccessfully. Although they know he is somewhere between Wainwright and Atkusuk, they are still searching an area of hundreds of square miles. The next day the weather has cleared enough to launch an aerial seach, but unfortunately the blowing snow has covered all traces of the hunter and snow mobile. After two more days the search is called off.

2002 Scenario

O.K. Fast forward to 2002. Another hunter prepares to depart on the same trip. This time, prior to his departure, he rents a PLB and files his trip report with North SlopeBorough Search and Rescue Department in Barrow. During the trip his snow mobile briefly turns into an airplane and he suffers the same fate. This time however, he reaches into his parka and activates his PLB. Two minutes later, theUSMCC receives an "unlocated" alert relayed through the GOES-9 satellite and transmits it to the AKRCC. North Slope Borough is then contacted. A brief check of their records shows who the PLB is checked out to and what his trip plan is. NSB rolls their Bell 214ST helicopter out of the hangar and prepares for launch. Twenty minutes after thePLB is activated SARSAT-4 comes streaking across the sky and pinpoints the PLB location to within a mile. The helicopter blades are just starting to spin when the pilot is handed the position still hot off the printer from theUSMCC. The weather has deteriorated and visibility is getting poor. Once in the area, the helicopter acquires the homing signal transmitted by the PLB on 121.5 MHz and quickly locates the hunter. He is transported back to Barrow where his broken leg is set and put in a cast. The next day, he's home with his family recuperating in front of a warm fire.