Air traffic in Brazil has been chaotic since a Boeing 737 crashed on September 29, exposing major problems in the country's aviation system and forcing the temporary shutdown of three airports amid its worst-ever aviation crisis.

The accident took place when the Boeing, operated by Brazilian carrier Gol Linhas Aereas, and a business jet collided in mid-air. The Boeing crashed nearby, killing 154 people.

Since the crash, the deadliest in Brazilian history, air traffic controllers have organized work slowdowns to protest poor pay and long hours, bringing air travel to a near-halt several times in the last two months.

Controllers have said their work load increased after the crash, with some saying they sometimes handled as many as 20 flights simultaneously.

The aviation crisis has also led to accusations of sabotage by disgruntled controllers, prompting Brazil's Congress to call a special session for next week to address the situation.

The crisis came to a head on Tuesday night, when officials were forced to temporarily close three major airports and cancel dozens of flights because of an apparent equipment failure that caused controllers to lose contact with planes.

"There has never been a day like this in Brazilian aviation," said Milton Zuanazzi, the aviation authority chief.

Officials blamed the breakdown on a technical glitch. But aviation experts questioned that explanation, saying the collapse may have been the result of sabotage by controllers who feel they are being made scapegoats for the Gol crash.

"There is no doubt that this was intentional," said Franco Ferreira, a retired Air Force colonel and aviation expert, on Wednesday in a radio interview.

Dozens more flights were delayed or canceled again on Wednesday, angering travelers around the country. In Brasilia, passengers protested the delays by donning red clown noses and blowing whistles as they waited in long lines.

Delays and cancellations have become commonplace since the Gol crash, prompting an avalanche of criticism of Brazil's civil-aviation system, which is run by the military. With air travel in Brazil growing at a double-digit pace, critics say the government has not done enough to keep up with demand.

As the crisis heated up late last month, President Luiz Inacio Lula da Silva fired the commander of the air traffic control system. But the situation has worsened, bringing calls for the resignation of Defense Minister Waldir Pires.

Pires is scheduled to go before a congressional panel next Wednesday to discuss the crisis.

Airlines are concerned that the situation could discourage travelers from flying.

"If things stay like this, traveling by plane is going to be like going to the dentist," said Marco Antonio Bologna, the chief executive of Brazilian airline TAM, recently.