A small plane that crashed in Alaska last month, killing all 10 people on board, was a half-ton overweight for the icy weather conditions under which it was flying, federal investigators said in their initial report Wednesday.

The plane, which disappeared Feb. 6 and was found the next day near the western coast of Alaska, was on a regularly scheduled afternoon flight between Unalakleet and Nome, a trip of about 150 miles.

Bering Air Flight 445 vanished about 10 minutes before it was set to arrive in Nome, according to the U.S. Coast Guard. When its position was lost, the aircraft was 12 miles offshore, it said.

After studying the baggage and cargo that was found, investigators with the National Transportation Safety Board determined that the weight of the plane at takeoff was about 1,000 pounds over the maximum takeoff weight for a flight heading into forecast or known icing conditions, according to guidelines. It was also about 800 pounds over the maximum takeoff weight for any flight operation, the investigators said in the nine-page report.

Excessive weight reduces flight performance, aviation experts say, in almost every aspect.

Weather conditions in the region between Unalakleet and Nome included snow, fog and low temperatures on the afternoon of the Feb. 6 takeoff.

A radar analysis showed that the Bering flight, a Cessna 208B Caravan, experienced “a rapid loss of altitude” and a “corresponding rapid loss in speed,” the Coast Guard said in February.

Before the plane disappeared, the pilot told air traffic control in Anchorage that he had intended to enter a holding pattern while waiting for the runway in Nome to be cleared, according to the Nome Volunteer Fire Department. Then the plane lost contact.

A pilot and nine passengers were on board the flight, said David Olson, the director of operations for Bering Air. Their Cessna Caravans are allowed to carry as many as nine passengers and two crew members, according to the Federal Aviation Administration.

Bering Air did not immediately return inquiries for comment Wednesday.

The NTSB investigation is continuing. Accident investigations typically take one to two years to complete, according to the agency.

More than 80% of communities in Alaska are inaccessible by road, according to the Alaska Transportation Department. Air connections, like those operated by regional carriers such as Bering Air, are critical for delivering supplies such as fuel and food.

Bering Air is based in Nome, with hubs in Kotzebue and Unalakleet, and operates flights to 32 destinations, according to its website. Nome is home to about 3,500 people, and Unalakleet about 800.

The Bering Air crash was the third involving an airline flight in the United States during an eight-day stretch from late January into early February. An Army helicopter collided with an American Airlines jet over the Potomac River on Jan. 29 as the jetliner approached Ronald Reagan National Airport, near Washington D.C., killing 67 people.

Two days later, a small medical plane carrying six people crashed near a shopping center in northeast Philadelphia on Jan. 31, killing everyone on board and one person on the ground, and sending a large fireball into the air that engulfed homes and vehicles in flames.

• This article originally appeared in The New York Times.