WRAPUP 4-Boeing, FAA officials called to testify in U.S. Senate on 737 MAX plane crashes

plane crashes@ (Recasts with Senate hearing, FAA notification and filing of lawsuit against Boeing)

* Unprecedented scrutiny for Boeing, U.S. aviation regulator

* Indonesia crash pilots could not control 737 MAX systems-sources

* Ethiopian investigators study black box data, voices

* Europe, Canada seek own certification for 737 MAX jets

ADDIS ABABA/JAKARTA/WASHINGTON, March 20 (Reuters) - Boeing Co faced growing pressure in Washington on Wednesday with U.S. lawmakers calling for executives to testify about two crashed 737 MAX jets even as the world's biggest planemaker works to overcome obstacles to returning the grounded fleet to the skies.

The Senate hearing, at an unspecified date, would be the first time that a U.S. congressional committee has called Boeing executives to appear for questioning about 737 MAX passenger plane crashes in October in Indonesia and March 10 in Ethiopia.

On March 27, the same panel, the Senate Commerce subcommittee on aviation and space, also will question U.S. Federal Aviation Administration (FAA) officials. They will likely be asked why the regulator agreed to certify the MAX planes in March 2017 without requiring extensive additional training.

Meanwhile, the FAA on Wednesday sent a notification to global aviation authorities saying the installation of Boeing's new automatic flight software in the grounded jets and related training was a priority for the agency.

The Ethiopian Airlines crash has shaken the global aviation industry and cast a shadow over the flagship Boeing model intended to be a standard for decades to come, given parallels with the Lion Air calamity off Jakarta in October. The two crashes killed 346 people in all.

Boeing was sued on Wednesday in federal court in Chicago by the estate of one of the Lion Air crash victims in which the plaintiffs referred to the Ethiopian crash to support a wrongful death claim against the company. A Boeing spokesman said the company does not respond to, or comment on, questions concerning legal matters.

Also on Wednesday, the Seattle Times, citing unidentified sources, reported the FBI was joining the criminal investigation into the MAX's certification. The U.S. Justice Department is looking at the FAA's oversight of Boeing.

Meanwhile, the Pentagon Inspector General said it would investigate a complaint that Acting U.S. Secretary of Defense Patrick Shanahan, a former Boeing executive, violated ethical rules by allegedly promoting Boeing while in office.

SOFTWARE UPGRADE

Chicago-headquartered Boeing has promised a swift update of software, but regulators in Europe and Canada are shifting away from previous reliance on FAA vetting, saying they will now seek their own guarantees of the MAX planes' safety.

Aviation experts suspect an automated system, meant to stop stalling by dipping the nose, may be involved in both cases, with pilots struggling to override it as their jets plunged downwards.

But they stress neither investigation is complete and crew actions and training will also be closely scrutinised.

As Ethiopian investigators pored over black box data from their crash, sources with knowledge of the doomed Lion Air cockpit voice recorder revealed how pilots scoured a manual in a losing battle to figure out why they were hurtling down to sea.

Investigators examining the Indonesian crash want to know how a computer ordered the plane to dive in response to data from a faulty sensor and whether pilots had enough training to respond appropriately.

Communications showed that in the final moments, the captain tried in vain to find the right procedure in the handbook, while the first officer was unable to control the plane.

At the end, the sources told Reuters, the Indian-born captain, 31, was quiet, while the Indonesian officer, 41, said "Allahu Akbar" ("God is greatest") - an Arabic phrase to express excitement, shock, praise or distress. The plane then hit water.

Boeing has said there was a documented procedure to handle the problem.

A different crew on the same plane the evening before had the same situation but solved it after running through three checklists, though they did not pass on that information to the doomed Indonesian crew, according to a preliminary report released in November.

Regulators want to be absolutely sure of Boeing's new automated control system, known as MCAS (Maneuvering Characteristics Augmentation System), and that pilots are fully prepared to handle it. It is meant to prevent a loss of lift which can cause an aerodynamic stall and send the plane downwards in an uncontrolled way.

Facing such high-profile scrutiny, Boeing reshuffled executives in its commercial airplanes unit to focus on the crash fallout.

VOICE RECORDINGS

The FAA said its "robust processes" and "full collaboration with the aviation community" were key to safety worldwide.

In Ethiopia, which is leading the investigation of the crash, experts were poring over the in-flight recording of the captain and first officer.

As with the Indonesia flight, they radioed about control problems shortly after take-off and sought to turn back, struggling to get their plane on track before it hit a field.

Ethiopia's civil aviation head Wosenyeleh Hunegnaw told Reuters he expected a report on the investigation within 30 days.

For now, more than 350 MAX aircraft are grounded, and deliveries of nearly 5,000 more - worth more than $500 billion - are on hold.

Development of the 737 MAX began in 2011 after the launch by its main rival of the Airbus A320neo. The MAX entered service in 2017.

While some airlines are worried about the impact on profits, they have been able to keep services going, swapping MAX planes for others, or using partner carriers.

(Reporting by Maggie Fick and Jason Neely in Addis Ababa, David Shepardson in Washington, Tim Hepher in Paris, Jonathan Stempel in New York, David Ljunggren in Ottawa, Jamie Freed in Singapore, Cindy Silviana in Jakarta, Eric M. Johnson in Seattle; Writing by Andrew Cawthorne and Ben Klayman; Editing by Jon Boyle and Grant McCool)