For anyone -- let alone a middle-age airplane mechanic from Fort Worth -- the plan to smuggle seven jetliners into Iran was audacious and risky.It involved planes in China, Swiss funds and a blacklisted Iranian airline. Federal prosecutors say Diocenyr Ribamar Barbosa-Santos, 52, of Fort Worth tried to broker the $136.5 million deal from Broward County, Fla.But it failed this month before a single Airbus A300 left the ground."It's not every day that someone walks into your office with a charge like this," said R. William Barner III, the Sunrise, Fla., attorney representing Barbosa-Santos.The suspect has been accused of violating federal trade restrictions. If convicted, the penalties include 20 years in prison and a $1 million fine.In Iran, the demand for commercial jets is becoming urgent.South Florida is a hotbed of illicit transactions of all kinds, investigators said, and some have involved Iran.Among them: In 2009, an Iranian woman was sentenced in Fort Lauderdale for trying to broker a deal for 3,500 pairs of night-vision goggles.In 2011, Felipe Echeverry, now a defendant in U.S. District Court, led undercover agents to a Miami warehouse where he was storing 22 F-5 fighter jet engines awaiting export to Iran.Barner is quick to distinguish between these cases and the charges Barbosa-Santos faces."I've seen nothing suggesting that it's anything related to military, nothing related to terrorism," he said.The United States outlawed dealings with Iran in 1995, before recent concerns about the nation's nuclear program. But government officials say sanctions on civilian aircraft buttress the security efforts.How Barbosa-Santos found his way into the fabric of a major international struggle is unclear. The U.S. attorney's office in Miami and agents at Homeland Security Investigations declined to talk about specifics of the case.The federal complaint says Barbosa-Santos was born in Brazil in 1960 and is a U.S. citizen. The only crime on his record was disorderly conduct and trespassing in 1997, when he was living in Fort Lauderdale, Fla. And he wasn't prosecuted, records show.In 2001, Barbosa-Santos registered a business called Aerojet Engineering, based a few hundred yards away from Dallas/Fort Worth Airport.Three years later, he registered Aerobraz Aircraft Marketing Corp. out of the same office. Barbosa-Santos signed paperwork as the president, vice president, treasurer and secretary. His mailing address was listed in suburban Fort Worth.In Miami, Barbosa-Santos obtained a mechanic license from the Federal Aviation Administration to work on airplanes.At some point between his beginning in the aviation industry and January 2012, Barbosa-Santos apparently started talking to people involved in a network of Chinese government officials and suppliers eager to tap into the Iranian market.For companies inside Iran, "it's been very difficult for them to engage in a legitimate financial transaction," said Alfred DeAngelus, a senior special agent for Homeland Security Investigations.Highflying schemeMoving seven commercial airplanes is easier than it may seem. According to federal court filings, Barbosa-Santos was planning to pay a Chinese source $19.5 million apiece for seven airplanes to then sell to Iran Air.Getting them into Iran would have involved complicity among high-ranking Chinese officials, said investigators and a veteran aviation consultant."The customs services of many nations and the police services of many nations, they're paid so poorly that there's a lot of corruption," DeAngelus said. "It's easy to pay somebody to turn their head."In February, a federal agent, acting on a tip from a confidential informant, arranged a meeting with Barbosa-Santos in Fort Lauderdale, prosecutors said in a federal complaint.Barbosa-Santos warned the undercover agent that they could both go to jail for the deal and added that he hoped to sweeten it with a C-130 cargo plane.Investigators took Barbosa-Santos into custody Nov. 2.