(Adds quotes from pilots' union, investigator) BRASILIA, Brazil, Nov 16 (Reuters) - Pilots and air traffic controllers made a flurry of unanswered calls to each other in the minutes before Brazil's deadliest plane crash, the government said on Thursday in a report that did not assign blame for the disaster. The preliminary report by the air force outlined basic flight and radio information but did not draw conclusions from details in the cockpit voice and flight data recorders, which will take months to analyze to find the cause of the crash. On Sept. 29, 154 people died when a Boeing 737-800 operated by Brazilian airline Gol <GOLL4.SA><GOL.N> and a Legacy corporate jet flown by New York-based charter service ExcelAire clipped wings. The Boeing broke up over the Amazon jungle, killing everyone on board, and the Legacy, built by Brazil's Embraer <EMBR3.SA>, made an emergency landing after losing a winglet. "So far, I don't have a way to say with exact certainty how the planes collided," said Col. Rufino Antonio da Silva Ferreira, the head of the investigation. "We need to have open minds and not have any preconceived notions." Investigators want to know why dozens of radio calls went unanswered, why neither plane's anti-collision system issued alerts, and why they flew toward each other at 37,000 feet (11,280 metres). In his blog, Joe Sharkey, a U.S. journalist who was on the business jet, has rejected previous comments by some officials that the Legacy pilots were performing tricks before the crash. The government's report made no mention of aerial stunts. The two U.S. citizens who piloted the Legacy, Joe Lepore and Jan Paladino, have been prevented from leaving Brazil since the crash. Lawyers for the pilots filed a request this week to get back their seized passports but a judge denied it. Silva Ferreira said the pilots should be freed, although only courts have the authority to let them go. "Their permanence in Brazil has nothing to do with the investigation," he said. The U.S. Air Line Pilots Association and the International Federation of Air Line Pilots Associations issued a statement urging their release. CONTROLLERS PROTEST During the past two weeks, air traffic controllers have staged work slowdowns by handling no more than 14 planes at a time instead of up to 20 to protest what they say is low pay and a lack of staffing. Ten controllers on duty at the time of the Gol crash were suspended, adding to workloads. The slowdowns have snarled air traffic, forcing customers to spend hours sleeping on concrete floors in terminals and Cabinet ministers to miss important meetings. The air force, which runs Brazil's air traffic control system, was so short-staffed this week it told controllers to bring toothpaste and shampoo to work because they might not be allowed to go home after their shifts. Controllers working during the crash will be interviewed. "The controllers will be a fundamental piece of this," Silva Ferreira said. In the United States, families of victims have filed two lawsuits against ExcelAire and Honeywell International Inc. <HON.N>, which made the Legacy's transponder. The lawsuits allege the Legacy pilots were flying at the wrong altitude and that the Honeywell transponder may have malfunctioned. Transponders track a plane's position relative to the ground and other aircraft to help avoid collisions. Honeywell has said its transponder was not responsible for the accident. ExcelAire has said its pilots would be exonerated and were acting on instructions from air traffic control.
