WASHINGTON (December 27, 2010)—Joseph Stack III, 53, told an air traffic controller to “have a great day” minutes before flying his Piper PA-28-236 into the side of the seven-story Echelon Building in Austin, according to the final National Transportation Safety Board report on the Feb. 18 suicide attack.

Stack died in the fiery crash along with Internal Revenue Service employee Vernon Hunter.

About a dozen other people were injured.

The building housed IRS offices in which about 200 IRS employees worked.

The NTSB report says Stack took off at 9:44 a.m. on Feb. 18 from Georgetown Municipal Airport and proceeded south, climbing to an altitude of 4,800 feet.

During the ascent, Stack requested a radio frequency change and told the controller who approved it, “Eight niner delta, thanks for your help, have a great day.”

Those were evidently Stack’s last words.

At 9:54 a.m., 10 minutes after takeoff, the plane was observed on radar as it descended from 4,800 feet and turned to the west.

The plane disappeared from radar three minutes later at an altitude of 1,000 feet.

A minute later, at 9:58 a.m., the plane slammed into the side of the office building between the first and second floors, exploding on impact.

Investigators found the plane’s engine and two of its three propeller blades and the right wing outside of the building.

The tail section came to rest on a ledge, from which it was partially hanging, the report said.

The left wing, portions of the fuselage and the third propeller blade were found inside the building on the second floor, the report said.

The flaps were fully retracted, suggesting the plane was flying at maximum speed at the time of impact.

An autopsy report released earlier this year said Stack died of blunt-force trauma and that his "entire body was pulverized."

The report said the remains included a severely burned upper body and a mangled lower body.

Stack posted a rambling online anti-government message before crashing his plane into the building.

It wasn't the first time a protester has gone after an Austin IRS building.

In 1995, Charles Ray Polk plotted to bomb the IRS Austin Service Center.

He was released from prison in October of 2009.

The tax protest movement has a long history in the U.S. and was a strong component of anti-government sentiments that surged during the 1990s.