LONDON -- Arrows are still fighting for their Formula One future after writing to the sport's governing body to explain their absence from the Belgian Grand Prix.

"The FIA has received a communication from Arrows which it is now studying," a spokesman for the International Automobile Federation said on Wednesday.

"Any further comment would be inappropriate at this stage."

Arrows have failed to compete in three of the last four races and left the Spa paddock on Friday night after failing to finalise a deal to sell the struggling team to an unnamed American investor.

The FIA had demanded a written explanation and had set Arrows a deadline of 5 p.m. GMT on Tuesday to respond.

FIA sources said the Arrows reply, which arrived only after close of business on Tuesday, would be studied carefully before any decision was made on what to do next.

The team, who missed last month's race in Hungary entirely and made only a token attempt to qualify in France in July, have argued force majeure -- or unavoidable circumstances -- in their defence.

A statement issued at Spa on Friday said that legal teams were "still working through the detailed documentation that supports the sale of Arrows" but had been unable to complete the process in time.

"Consequently the team has been advised to do nothing that could jeopardise the successful completion of the transaction, so will not race in Sunday's Belgian Grand Prix."

The media circus surrounding Arrows dominated the early part of the weekend and Formula One supremo Bernie Ecclestone, who controls the business side of the sport, suggested in Belgium that patience was running out.

"Enough was enough maybe a few races ago," he said.

"So we'll see what happens now. They are saying they are not here because it's force majeure, it's out of their control, and if they can prove that (then) maybe they've got chances to hang on.

"But if they can't, they probably won't go to Monza."

The Italian Grand Prix at Monza is on September 15 and before that Arrows have some major hurdles to overcome apart from satisfying the FIA and finalising their sale.

The manager of Jos Verstappen, dismissed by the team before the start of the season, said last week that a winding up order against the team brought by the Dutch driver and another party, was due to be heard next Tuesday.