In early 2012, Avantair was the darling of the charter plane industry and Tampa Bay business executives, a publicly traded company with a fleet of 56 executive airplanes and hundreds of employees based at St. Pete-Clearwater International Airport.

That's all gone now — Avantair collapsed in 2013, a year after federal investigators began looking into why one of its planes flew without a critical piece of its tail. Shoddy maintenance was ultimately to blame. Workers were furloughed, planes grounded, lawsuits filed and customers left out to dry.

Now a new chapter for Avantair has opened in federal court:

David Esteves, 52, a former director of maintenance at the defunct company, pleaded guilty on Friday to charges that he tampered with evidence. He was charged with interfering with National Transportation Safety Board and Federal Aviation Administration investigators looking into what led an Avantair plane's left tail elevator to fall off unexpectedly in 2012.

While no one else has been charged in this case, federal documents note that Esteves was acting at the suggestion of his superiors at Avantair. Amy Filjones, spokeswoman for the U.S. Attorney's Office in Tampa, said the federal investigation is ongoing. Esteves' lawyer, Scott Robbins, said in court Friday that Esteves was cooperating with authorities.

Before it failed, Avantair allowed wealthy individuals and companies to buy shares of each plane. They could schedule private flights on demand.

"As quickly as it was a good company, it was a bad debt," said financial adviser Neil Kishter, who was owed $100,000 in private flight time when the company went into bankruptcy.

According to federal records, the charges stem from Esteves asking a maintenance contractor in Las Vegas to cover up evidence after Avantair pilots landed at an executive airport in a Vegas suburb on July 28, 2012, only to discover their plane was badly damaged.

The pilots, speaking in the cockpit after a difficult landing, noted the unusual feel of the plane as they came in to the runway. It was soon revealed that the plane's left tail elevator, which allows the plane to pitch up and down, was nowhere to be found.

According to a statement by Leslie "Lefty" Kenyon, an aviation maintenance contractor, Avantair's maintenance dispatcher asked him to evaluate the damage and send him pictures.

After examining the plane's tail, Kenyon found that a nut on the right elevator was on the verge of falling off. The dispatcher asked him to tighten them. Kenyon refused — in those situations, planes are supposed to be quarantined for federal investigators.

A few days later, Esteves asked Kenyon to remove the right elevator and ship it to Clearwater. He also told him to run the aircraft for 30 to 45 minutes, Kenyon said in his statement to the NTSB. Kenyon said Esteves told him that would have wiped clean the data recorded by the plane's cockpit recording device. Kenyon refused.

The next week, Mark Keefer, an FAA safety inspector in Tampa, went to company headquarters to interview Esteves. According to the inspector, Esteves said he had difficulty remembering the details of his conversations with the contractor in Nevada.

Esteves, after conversations with a company vice president, eventually asked Keefer to give him the questions in writing.

Months later, Avantair voluntarily grounded its whole fleet for October 2012.

The picture worsened the next year. The FAA found the company wasn't properly tracking parts that due to safety regulations could only be flown on a certain number of flights before being replaced.

The fleet was grounded again, and employees were furloughed. Creditors moved swiftly to force the company into bankruptcy soon after in July 2013.

Owners scrambled to find their planes. Nine were found in a hangar Avantair rented at Dallas Love Field in Texas. According to owners, Avantair had cannibalized a good portion of them to keep other planes running. Engines were missing, and there was no record of how the planes had even ended up there.

Owners of those "donor planes" that were used for parts discovered at the bankruptcy in 2014 that they would lose much of the hundreds of thousands of dollars they had spent on the partial ownership of their planes.

The bankruptcy case eventually made it to the 11th Circuit Court of Appeals, which finally ruled in early 2016 that owners of dismantled planes would have to deal with what they had bought.

"When you start to get people who get behind financially in aviation, they just start to cut corners," said Don Andersen, who represented a private prison corporation that had partial ownership of three Avantair planes, one of which he said was in particularly bad shape.

A U.S. magistrate judge did not set a sentencing date for Esteves, who was released on his own recognizance. In court, his lawyer said it was difficult to say whether his client would face prison time.

Contact Nathaniel Lash at nlash@tampabay.com. Follow @Nat_Lash.