Beech 1900D Plane Based on Tested Design

Beech 1900D twin-engine turboprop airplanes of the type that crashed in North Carolina today are souped-up versions of a "tried-and-true" commuter and corporate plane design, ABCNEWS aviation consultant John Nance said.

"I usually call it a 'King Air' on steroids because it has a larger engine and bigger cabin," Nance said. "It does not have a bad history at all, and it is a very reliable, boilerplate, day-in-day-out-type of airplane."

The 8-year-old 1900D involved in today's crash at Charlotte/Douglas International Airport was operated for US Airways by Air Midwest, a subsidiary of Mesa Air Group, and has flown about 15,000 hours and made 21,000 takeoffs and landings, according to The Associated Press. Mesa operates about 50 of this model of aircraft.

There are two common Beech 1900 models — the 1900C, which began flying in 1982 and is no longer being produced, and the 1900D, the type of plane involved in the North Carolina crash. The 1900D is slightly larger and faster than the 1900C, and the Raytheon Aircraft Co. has been producing it in its Beechcraft line since 1991.

According to Jane's Defense Weekly, the U.S. Air Force ordered six Beech 1900C-1 "wet-wing" models in 1986, assigning two to the U.S. Army — and the Army also received a 1900D in 1997.

What Caused the Crash?

In August, the Federal Aviation Administration issued a maintenance alert for the Beech 1900 turboprop after attachment bolts for the vertical stabilizer were found loose on one plane during a scheduled inspection, the AP reported.

It is not yet clear what caused today's crash in North Carolina, though Nance said it appeared unlikely the problem in the maintenance alert could have contributed to the type of accident that occurred.

"There is never ever one single cause to an airline or an aircraft accident," Nance said. "There is always a multiplicity of causes and we refer to that as a causal chain.

"A failure to maintain directional flight control" could have occurred from a chain reaction, perhaps begun by engine failure, Nance said, though the type of engine on that type of plane "is probably the most reliable turboprop engine in history."

"We are taught constantly, and practice constantly, handling the loss of an engine just as we lift off," Nance said. "It's a very simple matter of rudder in the direction of the good engine and rolling the control yoke a little in the direction of the good engine, … and then making sure your pitch does not become excessive and your air speed [does not] get too low — because there is a minimum air speed below which you do not have enough control over the airplane to keep it going straight."

Nance added that Beech 1900Ds have a safety feature that allows disabled propellers to be "feathered" sideways to prevent drag on one side of the plane.

"If you cannot feather a dead engine's propellers, you have a worse problem," Nance said. "And if your air speed deteriorates too far, that lack of feathering ability can cause exactly the type of crash we see here."

Nance added evidence suggests other possible causes for the crash, as well.

"If indications from at least one eyewitness are accurate that this aircraft pitched up excessively immediately after departure," Nance said, "then one of the areas that inspectors would look at in addition to the engines would be the elevator that controls the pitch of the airplane and whether there was a malfunction there, and whether or not the aircraft was loaded properly or had an excessively aft center of gravity. Either, or a combination of both, could give you an excessive pitch up."

A sharp pitch upward could lead to a dangerous loss of air speed, and might prompt the pilot to roll the airplane in one direction or another in an attempt to lower the plane's nose and to regain control, Nance said.

ABCNEWS' Michael S. James contributed to this report.