(CNN) - Several countries have grounded Boeing’s 737 Max 8 jets following Sunday’s deadly crash in Ethiopia.
Still, some pilots, according to a federal database accessed by CNN, have anonymously reported issues with the plane while flying over the U.S.
In two complaints, there were reports of the plane's nose briefly being forced down because of a problem with the jet's autopilot feature.
No crashes or injuries were reported in those incidents.
Another pilot also said the flight manual for the 737 Max 8 is “inadequate and almost criminally insufficient.”
The pilots and their airlines were not identified but only two U.S. carriers currently fly the 737 Max 8: American Airlines and Southwest.
Sunday's crash in Ethiopia that killed all 157 people on board followed a crash last October of Lion Air flight 610 - also a 737 Max 8.
There were 189 passengers and crew members killed.
The Federal Aviation Administration is standing by the plane's safety and has so far declined to ground the plane in the U.S.