American pilots who flew the Boeing 737 Max had registered complaints about the performance of the jet months before the fatal Ethiopian Airlines crash.
According to media reports, most pilots mentioned issues with the aircraft's autopilot and the plane going nose down shortly after takeoff.
One pilot reportedly wrote that the Max 8 aircraft manual was "criminally insufficient".
The US regulator, the Federal Aviation Administration, has since grounded the entire fleet after investigators uncovered new evidence at the scene of the Ethiopian crash.
From Washington, Daniel Ryntjes reports:
Man charged with 10 counts of attempted murder after knife attack on UK train
Tanzania's Hassan sworn into office after deadly election violence
Powerful 6.3 quake kills at least 20 in Afghanistan, hundreds injured
Turkey set to call for action on Gaza as soon as possible, source says
