DENVER -- Rep. Tom Tancredo on Friday said he wants top officials of the Federal Aviation Administration and National Transportation Safety Board replaced for what he calls a "failure to act responsibly for hundreds of deaths."

This specifically involves an airplane that was the focus of a 7NEWS investigation -- the Mitsubishi MU-2.

7NEWS began investigating the safety of the MU2 after back-to-back crashes near Centennial Airport in which three pilots died.

Since the 7NEWS investigation ran in October of last year four more MU-2s have crashed, killing six people. Industry reports show that the aircraft has among the worst fatal accident rate of any similar twin-engine turbo-prop.

The exact cause of the most recent crash is not known but pilots and witnesses of previous crashes have reported engine problems before the planes became unstable, rolled and crashed.

Many believe the MU-2 has a deadly design flaw, 7NEWS Investigator John Ferrugia said.

Others blame the crashes on untrained pilots.

This week, Tancredo sent a letter to President George W. Bush asking him to consider replacing the top officials with the FAA and NTSB, saying, "As far back as the spring of 2005, I asked the FAA to 'ground' the Mitsubishi MU-2 series aircraft due to its shockingly high accident rate. Because [they] have consistently failed to take appropriate action on this issue despite repeated warnings about the aircrafts suitability for use, I believe the public would be well served if they were replaced by administrators willing to act swiftly and deliberately on this matter."

Tancredo will also introduce legislation to ban the MU-2 in United States airspace until a thorough safety evaluation of the plane is completed by the FAA.

Recently, the FAA said it would issue a special regulation requiring pilots to undergo specific, enhanced training to operate the airplane. Tancredo said that regulation is still not in place.

Officials with Mitsubishi claim the plane is safe, but agree it's difficult to fly without proper training. Mitsubishi and the NTSB blame most of the crashes on pilot error.

About 12 percent of all the MU-2s ever made have been involved in fatal crashes. And according to an industry report prepared for the international business aviation association, the overall accident rate of the MU-2 is about 78 percent higher than other twin-engine turbo-props in its class.

Conservative estimates indicate that as many as one-quarter of the aircraft produced have crashed, resulting in the deaths of more than 250 people in nearly 200 separate incidents in the U.S. alone, according to Tancredo's office.

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