WASHINGTON - He was described as a pilot who had "hands of silk" and "did everything by the book."
Yet despite his skills, federal air safety investigators are trying to discern whether Sten Molin could have made a mistake that caused the tail to rip off American Airlines Flight 587.
Co-pilot Molin, who was at the controls of the Airbus A300, was the man in the middle of this week's National Transportation Safety Board hearings on the crash. The accident last Nov. 12 killed all 260 aboard and five people on the ground in a New York neighborhood.
Molin's actions have become the focal point of an acrimonious battle between Airbus and American. The two companies could share tens of millions of dollars in monetary liability over the causes of the crash.
While not directly pointing fingers, Airbus witnesses have insisted that nothing was mechanically wrong with the plane. They suggested the tail fin failed because of Molin's overly aggressive use of the rudder to handle turbulence from the wake of a larger plane. Molin had been criticized for overusing the rudder once before.
American contends that Airbus did not adequately inform its airline customers of the tail fin's vulnerability to abrupt, back-and-forth rudder movements. Tensions between the companies spilled over Thursday in a discussion of a tangential issue: whether they fully cooperated in addressing safety concerns from a turbulence incident in the late 1990s.
By all accounts, Molin, 34, the son of an airline pilot, was gifted and careful. But if he is ultimately blamed for the Flight 587 crash, his use of the rudder last November could become a textbook example of what not to do.
Capt. Sam Mayer, who flies for American Airlines out of the New York area, said Molin was known as a meticulous professional with an upbeat attitude and a broad range of interests and friends. Molin was a gourmet cook and a computer whiz since his teens who also loved pursuits such as sailing.
"He didn't fit the mold of your crusty old pilot," Mayer said. "He was a lot more erudite."
Molin was hired by American Airlines in 1991, after working for smaller carriers. The voluminous accident case file is full of details about Molin's habits. He was an early riser and a nonsmoker. At 5-foot-11, he weighed a trim 165 pounds.
As a youth in Greenwich, Conn., Molin had volunteered for a program that provided rides for teens who might have been drinking. As an adult, he rarely drank alcohol.
The one question mark in Molin's professional background was revealed by Capt. John Lavelle, a senior Boeing 737 pilot for American. In an interview this summer with the NTSB, Lavelle reported that five years ago, he had criticized Molin for overly aggressive use of the rudder during a takeoff.
The rudder is a movable panel on the rear edge of the vertical tail fin. Operated by a system of pedals, its main use is to keep a plane flying straight when landing or taking off in a crosswind, or if an engine fails.
NTSB investigators said in a report that Lavelle told them Molin had "excellent flying abilities but one strange tendency: to be very aggressive on the rudder pedals."
Lavelle said he had seen evidence of this once in 1997.
The Boeing 727 they were flying encountered turbulence during a takeoff, and Molin "stroked the rudder pedals 'one-two-three, about that fast,'" the NTSB report said. The effect was to create sharp, uncomfortable sideways forces on the airplane.
When he challenged Molin, Lavelle said, the co-pilot explained that he was following training guidance provided by American under an advanced maneuvering program for pilots. The program had been criticized by industry and government officials for advocating too much reliance on the rudder. American revised it well before the crash.
On Flight 587, sharp rudder movements stressed the plane's vertical tail fin beyond its design limits and caused it to fail. Investigators have not confirmed that the motions were caused by Molin, but no mechanical malfunction has been identified.
Ricardo Alonso-Zaldivar and Eric Malnic write for the Los Angeles Times, a Tribune Publishing newspaper.