• The Boeing 737 Max has been grounded since last March
  • The grounding has sent Boeing revenue plummeting and seen orders fall to their lowest level in years
  • The FAA has been notified about the problem but it was unclear if it would delay the recertification process further

Boeing reportedly has notified the U.S. Federal Aviation Administration of a new software problem with the grounded 737 MAX that potentially could further delay the plane’s return to service.

The 737 MAX was grounded last March following two fatal crashes caused by a faulty sensor reading that sent the planes into death dives. Bloomberg reported Friday the latest issue involves a software system that monitors data systems to make sure they’re functioning properly.

Word of the problem sent Boeing (BA) stock down more than 2% in late afternoon trading.

“We are making necessary updates and working with the FAA on submission of this change, and keeping our customers and suppliers informed,” Boeing said in a statement emailed to Bloomberg. “Our highest priority is ensuring the 737 MAX is safe and meets all regulatory requirements before it returns to service.”

Boeing is facing billions in losses with production on the 737 MAX suspended. The company had been hoping the plane would be back in service this spring, but the FAA has said it will not issue an approval until a series of milestones are met. New orders have fallen to their lowest level in decades and fourth quarter results, due Jan. 29, are expected to show a 26% drop in revenue.

Boeing stock also could be downgraded as the company considers raising cash to bolster reserves in expectation of having to pay damages for the two crashed.

American, United and Southwest airlines have pulled the 737 MAX from their schedules until June.

New CEO Dave Calhoun took the helm earlier this week, just as a trove of emails painting a disturbing picture of the plane’s development was made public.

“This airplane is designed by clowns who in turn are supervised by monkeys,” one of the emails read.

The FAA said there was nothing new in the emails and they would not affect the recertification process.

Little more than a week ago, Boeing revealed a wiring problem with the plane but it was not immediately clear if it would pose any danger.

The 737 MAX was taken out of service last March following the crashes of Lion Air and Ethiopian Airlines flights that killed 346 people. The crashes were caused by a glitch in the software that erroneously sent the planes into nose dives.