On the morning of September 5, 2012, Era Alaska Flight 874 departed Ted Stevens Anchorage International Airport for what was scheduled to be a 40-minute flight to Homer.

The de Havilland DHC8 twin-turbine aircraft, more commonly known as a Dash 8, carried 15 passengers and a crew of three (two pilots, one flight attendant). At about 11 a.m., according to a preliminary report later filed by the National Transportation Safety Board, the aircraft "experienced an uncommanded left roll and uncontrolled descent during climb at about 12,000 feet."

The flight crew regained control at about 7,000 feet and the flight returned to Anchorage with no injuries or damage to the aircraft.

More than three years later, The NTSB hasn't issued a final report finding a probable cause for the incident.

NTSB Public Affairs Officer Eric Weiss, said the investigation is being handled by the agency's Washington, D.C. office, not by Anchorage investigators.

"When a major incident or accident occurs, it may be handled by D.C.," he explained in a phone call. The 2012 Era incident could be considered "major" due the type of operation, a scheduled commuter flight, and the size of the aircraft. According to NTSB databases, only one other Alaska investigation from 2012 remains open, a February incident involving a mechanical problem with Everts Air Cargo. That investigation is also being handled by the NTSB's Washington office.?

Passenger Vince Tillion, who holds a commercial pilot's license and builds aircraft for personal use, said he believes the plane entered a full aerodynamic stall.

"The weather was lousy when we took off and the props threw a lot of ice as we flew through the clouds," he said in a phone conversation. (The preliminary report states that instrument meteorological conditions, frequently abbreviated as "IMC," prevailed in Anchorage at the time.) "We were up on top of the clouds when it happened though."

"There was a classic pre-stall buffet (shaking), then the left wing dropped and we fell into the IMC and we kept falling for several thousand feet. That's when I texted my wife that I thought we were going to crash."

A pilot operating in instrument conditions would encounter reduced visibility down to even whiteout conditions. The weather could also include fog, rain, snow and ice, which under some conditions, can quickly build up on an aircraft.

Other similar commuter aircraft have been involved in stalls in recent years. The most tragic case involved a Colgan Air Dash 8 that crashed near Buffalo, New York in 2009 killing all 49 people onboard and one person on the ground. The NTSB determined that, among other human factors, the captain's actions led to an aerodynamic stall "from which the aircraft did not recover."

Era Flight 874 was required by federal regulations to have both a cockpit voice recorder and a flight data recorder onboard, which could provide investigators further insight.

Asked about the delay in determining a probable cause in the incident, the NTSB's Weiss replied only that "The NTSB tries to handle all cases in as timely a manner as possible. Unfortunately, we come up against staffing and resource constraints."