(This April 4 story has been refilled to correctly say victim was Ralph Nader's grand-niece, not niece)
By Jason Neely
ADDIS ABABA (Reuters) - Ethiopia Airlines' doomed 737 MAX jet hit excessive speed and was forced downwards by a wrongly-triggered automation system as pilots wrestled to regain control, a preliminary report into the crash that has shaken the aviation world showed on Thursday.
Three times the captain Yared Getachew cried "pull up", before the Boeing plane plunged into a field six minutes after takeoff from Addis Ababa last month, killing all 157 passengers and crew, said the report by Ethiopian investigators.
The disaster - and parallels with another 737 MAX crash in Indonesia where 189 people died last October - has led to the grounding of Boeing's flagship model.
It has also brought uncomfortable scrutiny over new software, pilot training and regulatory rigor.
While the Ethiopian Civil Aviation Authority's Accident Prevention and Investigation Bureau had a remit to investigate rather than blame, it implicitly pointed the finger at Boeing by defending the pilots, recommending the U.S. company fix its control systems, and saying regulators must be certain before allowing the MAX back in the air.
"The crew performed all the procedures repeatedly provided by the manufacturer but was not able to control the aircraft," Transport Minister Dagmawit Moges told a news conference.
"Since repetitive uncommanded aircraft nose down conditions are noticed ... it is recommended that the aircraft control system shall be reviewed by the manufacturer."
Boeing, the world's biggest planemaker and one of the United States' most important exporters with a $500 billion order book for the MAX, says a new software fix for its anti-stall system will enable pilots to always override if necessary.
According to the report by the Ethiopian investigators, an alarm indicating excess speed was heard on the cockpit voice reporter as the jet reached 500 knots (575 miles per hour) - well above operational limits.
FRAGMENTS IN A CRATER
The plane had faulty "angle of attack" sensor readings, its nose was pushed down automatically, and the crew lost control despite following recommended instructions, it said.
"Most of the wreckage was found buried in the ground," the report said, indicating the strength of the impact on an arid field in an agricultural zone. No bodies were recovered, only charred fragments among the debris in a crater.
Boeing has seen billions wiped off its market value since the crash, but its shares actually rose 2.4 percent on Thursday. Morgan Stanley said the report of flight control problems, which Boeing was already trying to fix, meant a "worst case scenario" of a new cause was probably off the table.
Families of the victims, regulators and travelers around the world have been waiting to find out to what extent Boeing technology or the pilots' actions played a role.
A final report is due within a year.
The preliminary report into the Lion Air disaster in Indonesia suggested pilots also lost control after grappling with so-called MCAS software, a new automated anti-stall feature that repeatedly lowered the nose based on faulty sensor data.
"It had to take a second disaster to wake up the major players to pay attention to something that could've been resolved after the first disaster," said one woman, who lost her father in the Ethiopian crash, asking not to be named.
"Whatever the issues were, they better be 110 percent sure about their resolution, otherwise the 157 lives lost would have been for nothing if something like this happens again. This is a lesson to not take shortcuts in order to try and save bucks."
"PROFITS OVER SAFETY"?
U.S. regulator the Federal Aviation Administration, under fire for its certification of the MAX, cautioned the inquiry was not over. "As we learn more about the accident and findings become available, we will take appropriate action," it said.
Boeing may press to know how crew members responded to problems triggered by the faulty data. Questions on whether the pilots had leveled out the plane before disengaging MCAS and how many times MCAS activated were not answered at the news conference in Addis Ababa that lasted about 40 minutes.
The New York Times quoted Dagmawit as saying pilots turned MCAS off and on, which is not the step recommended in published Boeing procedures telling crew to leave it off once disabled.
With bereaved families angry and confused, relatives of one woman killed in the Ethiopian crash filed the first lawsuit on behalf of a U.S. victim in Chicago.
The complaint accused Boeing of putting "profits over safety" and also targeted Rosemount Aerospace, the manufacturer of the angle of attack sensor.
U.S. consumer activist Ralph Nader, whose grand-niece died in Ethiopia, called for consumers to boycott the MAX.
Pilots around the world were watching closely too.
"If the preliminary report from the Ethiopian authorities is accurate, the pilots quickly identified the malfunction and applied the manufacturer's checklist," said Captain Jason Goldberg, spokesman for Allied Pilots Association, which represents American Airlines pilots.
"Following this checklist did not appear to allow the pilots to regain control of the aircraft."
(Reporting by Jason Neely in Addis Ababa, Eric Johnson in Seattle, Katharine Houreld and Maggie Fick in Nairobi, Tim Hepher in Paris, Jamie Freed in Singapore, Tracy Rusinski in Chicago, David Shepardson in Washington; Writing by Andrew Cawthorne; Editing by Alexandra Hudson)