All Boeing 737 Max-8 and 9 planes will continue to be grounded until May after the catastrophic Ethiopian Airlines crash, the US Federal Aviation Administration said.
The announcement comes as French air crash investigators released an image of the plane's flight ‘black box' flight data recorders recovered from the crash that killed 157 people on Sunday, reports the BBC.
Ethiopian Airlines Flight 302 was the second deadly crash of the same new plane type within five months. The crash of Lion Air Flight 610 shortly after takeoff from Jakarta last October killed all 189 people on board.
Similarities between them have led to attention focusing on technology designed to stop the jets from stalling.
The FAA said on Wednesday a software upgrade being worked on following the Lion Air crash would take months to complete.
Yesterday the FAA said 737 Max airliners would not be allowed to fly until new software had been 'tested, approved and installed', a process likely to last until May, according to US politicians briefed on the situation.
US Representative Rick Larsen said the software upgrade would take a few weeks to complete, and installing it on every plane would take 'at least through April'.
Meanwhile, France's Bureau of Enquiry and Analysis for Civil Aviation Safety (BEA) in Paris has tweeted a picture of the Flight Data Recorder (FDR), provided by the Ethiopian investigation team, reports CNN.
In Ethiopia, which lacks the forensic capabilities of other countries, a spokesman for Ethiopian Airlines said the black box voice and data recorders recovered on Monday had been sent overseas for analysis.
'There is no capacity here so the black box will be sent elsewhere for analysis. The investigation team will decide where,' the spokesman told Reuters.
Meanwhile, Boeing stocks continue to slide on the US stock market. Shares in the aviation giant fell half a percentage point in trading.