A new report on the 2013 crash of a Hageland Aviation plane in Western Alaska that killed four people, including an infant, says employees didn't follow the company's risk-avoidance policies in preparations for the fatal flight.

The National Transportation Safety Board released a factual report Wednesday morning on the crash of the Cessna 208B, which struck terrain near the St. Marys airport at about 6:24 p.m. on Nov. 29, 2013. Pilot Terry Hanson, 68, died in the crash, as did passengers Richard Polty, 65, Rose Ann Polty, 57, and 5-month-old Wyatt Coffee. Responders at the time said all six surviving passengers had major injuries, including broken bones.

Information released by the NTSB last year suggested a "bush pilot mentality" at Hageland was also a factor in the crash, which occurred during a flight from Bethel to Mountain Village and St. Marys. Investigators with the board said Hageland, now one of the three airlines that fly as Ravn Alaska, has made significant safety improvements since the St. Marys crash and a 2014 crash near Kwethluk that killed Hageland pilots Derrick Cedars, 42, and Greggory McGee, 46. In a second preliminary report released Wednesday, the NTSB said no transmissions were received from the pilots in the Kwethluk crash.

According to Wednesday's report on the St. Marys crash, Hageland used an internal risk-assessment scale from 1 to 4 for flights, with the number assigned by flight coordinators. A coordinator assigned Hanson's flight an assessment level of 2, due to night flying and runway conditions at the destination airports, then assigned a second coordinator to create a manifest for the flight -- which listed Hanson and eight passengers on board but not the infant.

"A risk assessment level 2 required a conversation between the flight coordinator and the pilot about possible hazards associated with the flight," investigators wrote. "However, the flight coordinators did not discuss with the pilot the risk assessment level assigned to the flight, current weather conditions or hazards, or ways to mitigate the hazards as required by the risk assessment program. Neither of the flight coordinators working the flight had received company training on the risk assessment program."

The NTSB said airmen's meteorological observations for the St. Marys area on the night of the crash included a forecast of "mountain obscuration conditions due to clouds and precipitation," as well as light snow showers, few clouds at 500 feet and a cloud ceiling at times as low as 2,000 feet. An earlier forecast also called for "isolated moderate icing" between 3,000 and 9,000 feet along both coastal and inland areas near the airport.

The scheduled 5 p.m. flight took off late from Bethel at 5:41 p.m., with Hanson accurately reporting 10 people on board by radio. He encountered dense fog and icing on the plane's struts en route to Mountain Village, however, and asked the Air Route Traffic Control Center for clearance to divert directly to St. Marys due to the deteriorating weather.

"At (6:19 p.m.), an Anchorage ARTCC controller cleared the flight into the St. Mary's surface area, told the pilot to maintain special (visual flight rules) conditions, and provided the St. Mary's altimeter setting," investigators wrote. "This was the last communication with the airplane."

Witnesses on the ground in St. Marys reported seeing the Cessna pass the airport's runway at an altitude of 300 to 400 feet before disappearing into the clouds. They tried to raise the aircraft on the radio, but soon got word from a pilot in the area that an emergency locator transmitter was active in the area. The plane was found about an hour later roughly a mile southeast of the airport, with three of the four people killed in the crash dead at the scene. A fourth died after being taken to a local clinic.

The St. Marys airport reported visibility at 3 statute miles with 6-knot winds from the southwest less than 10 minutes before the crash, with a cloud ceiling at 300 feet.

NTSB investigators discovered the plane lying in snow-covered tundra, at the end of a 200-foot wreckage path, with Hanson's seat crushed and the left front seat filled with snow that had entered the cabin during the crash.

An examination of the plane's instruments showed that it had begun a right turn, descending at about 835 feet per minute, from an altitude of 800 feet roughly 60 seconds before impact.

ARTCC staff heard clicks shortly beforehand from Hanson's microphone, similar to those used to trigger pilot-controlled approach lights at airports including St. Marys. Investigators found that the crashed plane's radio hadn't been switched to the airport's frequency, a necessary step in triggering the lights.

"Witnesses on the ground at St. Mary's reported that the pilot-controlled airport lighting system was not activated when they saw the accident airplane fly over the airport," investigators wrote. "A passenger reported that no lights were visible but that she saw the ground about 30 feet below the airplane and was able to make out dark patches of trees."

In addition, the plane was fitted with a terrain avoidance warning system that provided pilot warnings when the aircraft was at low altitudes. Investigators said the device had an "inhibit" switch, meant for use during clear conditions or near airports with known approach obstacles, which "should NOT be engaged for normal operations." But in the warning system's 10,485 hours of flight time on board the aircraft, the NTSB found, it had been left in "inhibit" mode for 9,277 hours.

"Examination of the airplane's cockpit instruments revealed that the terrain inhibit switch was in the 'inhibit' mode at the time of the accident," investigators wrote.

Wednesday's report reiterated work by the Federal Aviation Administration and Hageland to improve the company's flight standards.

"In the months following the accident, both the FAA and the operator initiated numerous safety improvements, including but not limited to, increased FAA surveillance, changes to company training programs, changes to company management, addition of established routes and increased limits for special VFR operations, and the establishment of a company operations control center to handle release and dispatch of flights," investigators wrote.