Ethiopian Airlines Flight 302 crash: Preliminary report says pilots followed Boeing's guidance

• The March 10 crash of Ethiopian Airlines Flight 302 killed all 157 passengers and crew on the Boeing 737 Max 8 jet.
• Data has shown significant similarities between the crash and the Lion Air disaster in October, when the same model of plane crashed soon after take-off.
• All Boeing Max jets have been grounded worldwide as the investigations continue.
• Ethiopian officials say the pilots followed instructions provided by Boeing.
• Ethiopian Airlines says the initial report "clearly showed" its pilots followed guidance provided by Boeing and approved by the FAA.

The Ethiopian government briefed journalists Thursday on the initial findings of its investigation into the crash of Ethiopian Airlines Flight 302. Both the government and the airline said a preliminary report by Ethiopian authorities shows the doomed jet's crew followed guidance provided by Boeing on how to fly the plane, including emergency procedures, but failed to regain control of the jet, putting the blame largely on the manufacturer.

The full preliminary report was released on Thursday.

The Boeing 737 Max 8 jet crashed just after takeoff from the Ethiopian capital Addis Ababa on March 10, killing all 157 passengers and crew on board.

Similarities between the disaster and the crash of a Lion Air 737 Max 8 in October last year have brought huge pressure on Boeing. Both crashes have been linked to a new flight control system that the American aviation giant installed on the Max series of jets, known as MCAS. What has remained unclear -- and will remain unclear until the investigation is complete and made public -- is the extent to which a malfunctioning MCAS system caused the crashes, versus pilot error.

"The crew performed all the procedures repeatedly provided by the manufacturer but was not able to control the aircraft," Ethiopia's Minister of Transport Dagmawit Moges said on Thursday.

CBS News transportation correspondent Kris Van Cleave reported on Wednesday that investigators increasingly believe that after take-off, something happened to one of the external sensors linked to the MCAS system on the Ethiopian jet and it began to send erroneous information, triggering the system. This is similar to what data show happened on the Lion Air flight.

The similarities between the two crashes have prompted governments and airlines worldwide to ground all of their Max jets -- the newest passenger aircraft made by Boeing. Hundreds of the planes remain on order from airlines around the world, so there are huge implications for both air passengers, and a major U.S. employer from a business standpoint.

Boeing releases a statement

Boeing Commercial Airplanes President and CEO Kevin McAllister said in a statement the company will carefully review the preliminary report released Thursday and "take any and all additional steps necessary to enhance the safety of our aircraft."

"The preliminary report contains flight data recorder information indicating the airplane had an erroneous angle of attack sensor input that activated the Maneuvering Characteristics Augmentation System (MCAS) function during the flight, as it had during the Lion Air 610 flight," Boeing said in a statement.

"To ensure unintended MCAS activation will not occur again, Boeing has developed and is planning to release a software update to MCAS and an associated comprehensive pilot training and supplementary education program for the 737 MAX."

"As previously announced, the update adds additional layers of protection and will prevent erroneous data from causing MCAS activation. Flight crews will always have the ability to override MCAS and manually control the airplane."

More information still needed

CBS News' Van Cleave notes that, in light of the assertions made by Ethiopian officials and the airline on Thursday, questions remain over how closely the doomed jet's crew followed the guidance given by Boeing regarding the MCAS system.

At no point has Boeing or anyone else recommended switching the MCAS system back on after it engages in error. As noted below, the Ethiopian Transport Minister confirmed on Thursday that the Flight 302 crew did take that action, at least once, and it remains unclear why.

Van Cleave says the Ethiopian officials stressing that the flight crew followed "all the procedures repeatedly provided by the manufacturer" also requires further explanation, as the guidance provided by Boeing in the wake of the Lion Air crash in October was not as straight forward as a, "step 1, step 2, step 3, repeat" set of instructions.

That is not to say that Boeing's design wasn't a principle factor in the crash, but more information was still needed, and there won't be any conclusions on what caused the crash until the final report is released within a year.

U.S. aviation authority reacts

The U.S. Federal Aviation Administration said in a statement that the preliminary report released on Thursday, "was prepared by the Ethiopian Civil Aviation Authority (ECAA) to share certain information obtained during the early stages of investigating."

The FAA noted that the Ethiopian government's probe "remains ongoing, with the participation of the FAA" and the U.S. National Transportation Safety Board -- the American government's accident investigation agency.

"We continue to work towards a full understanding of all aspects of this accident," the FAA said. "As we learn more about the accident and findings become available, we will take appropriate action."

As noted below, the FAA has also come under intense scrutiny in the wake of the Ethiopian Airlines crash, over its close working relationship with Boeing and other manufacturers in the certification process for new planes and the highly-complex systems that make them work in this day and age.

No bird strike

The Transport Ministry said there was no indication that Flight 302 had struck a foreign object after take-off from Addis Ababa.

Data from the plane's black boxes show no reason to believe that a bird or other object hit the plane or one of its engines. Bird strikes are relatively common and a large passenger jet's engines can usually cope with the damage, but they have been linked to previous crashes.

Pilots did turn MCAS back on

The Ethiopian Transport Minister on Thursday confirmed to CBS News that the crew of Flight 302 did switch the faulty MCAS system back on after initially disabling it when they encountered problems.

As CBS News' Van Cleave has reported, they are believed to have done so as many as four times, and it remains unclear why they would have taken that action, but it raises questions about the guidance provided to airlines by Boeing, which knew the system had issues following the Lion Air crash in October.

Minister of Transport Dagmawit Moges told CBS News that data showed the crew turned the system back on at least once after initially shutting it off. She said investigators were still waiting for the full report to confirm how many times that action was taken, and other details about the flight control software.

Ethiopian Airlines blames Boeing

Ethiopian Airlines released a statement on Thursday, as the Ministry of Transport news conference was still going on, saying the preliminary report "clearly showed" that the Flight 302 crew "followed the Boeing recommended and FAA approved emergency procedures."

"Despite their hard work and full compliance with the emergency procedures, it was very unfortunate that they could not recover the airplane from the persistence of nose diving," the statement said.

Ethiopia says crew followed instructions

The Ministry of Transportation said the Ethiopian Airlines crew on the doomed flight followed all of the rules and guidance provided by Boeing, but they still were unable to regain control of the jet. She said the findings were based on information from both of the planes black boxes, the flight data and cockpit voice recorders.

Dagmawit Moges, Ethiopia's Minister of Transport, said the onus was on Boeing to investigate the automated flight control system linked to the crash, but she did not specifically name the MCAS system.

She said the full report on the crash would be issued by the government within one year.

CBS News' Van Cleave noted on Wednesday that the Ethiopian government and Ethiopian Airlines were widely expected to try and put the lion's share of the blame for the crash on the plane's manufacturer, while Boeing will have a clear interest in showing any fault the flight crew might have had.

The truth, said Van Cleave, will likely end up being somewhere in the middle, but it is undeniable that had Boeing not deployed the new MCAS system with clear and fundamental flaws, the Ethiopian pilots would not have found themselves in a situation where they were fighting against it to try and control their aircraft.

The tragedy, like most transportation accidents, was likely to end up being blamed on a series of contributing factors, but Van Cleave said it would be difficult to place the blame entirely on the pilots, regardless of how they handled the response to the emergency.

FAA also under scrutiny

Boeing announced a software fix last month for the MCAS anti-stall system, intended to make it less aggressive and easier to control, but the 72 Boeing Max's in use in the U.S. were to remain grounded until the FAA approves Boeing's updates, which could take months.

"There is an extreme amount of pressure for Boeing to find a fix and for the FAA to validate the Boeing finding," former NTSB investigator Jeff Guzzetti has told CBS News. "Boeing is taking a black eye -- they're already taking a black eye. And so is the FAA quite frankly.

"I think much of this is not deserved and will be short lived," Guzzetti added, "but it's certainly creating fear and the lack of confidence in Boeing customers and those that trust the FAA."

Attorney Steven Marks filed the first lawsuit against Boeing connected to the Max 8 crash in Ethiopia. He believes the company's rush to catch up to rival Airbus in 2015 led to design mistakes that turned deadly.

"It's hard to have a great deal of confidence when the regulatory agency allowed this product and Boeing participated and having this product going to market without a complete review," Marks said.

CBS News' Van Cleave reported last month that with the technology on modern passenger jets advancing so fast and resources being so tight, the FAA -- long the gold standard in airline safety regulation -- has worked increasingly closely with manufacturers.

Federal authorities have told employees at Boeing and the FAA to retain documents relating to the plane's approval process, which by design relies heavily on manufacturers like Boeing to self-police. Scott Brenner, a former associate administrator at the FAA, told CBS News last month that the FAA does not have the resources to certify aircraft without the help of the manufacturer.

"On some level, the FAA is taking Boeing's word for a lot of this," Van Cleave pointed out.

"They are taking Boeing's word, but they - Boeing is also presenting data to prove their word," Brenner said. As far back as 1993, the government accountability office warned "FAA's certification staff were falling far behind industry in technical competency" in part because of delegating to manufacturers.

What happened on Flight 302

The Ethiopian Airlines pilots did initially follow Boeing and the FAA's suggested Emergency Procedures and turned off an electronic system to shut down the MCAS system soon after take-off. MCAS was designed to push the nose of a plane down if it is climbing too steeply, which can cause a stall.

But Van Cleave's sources said the pilots struggled to regain control of the plane even after turning the system off.

Data from the plane's black boxes indicate the pilots then deviated from the emergency procedures by turning back on the electronic system, which meant the MCAS kicked back into action. Over the following minutes, the MCAS system is believed to have reactivated as many as four times, pushing the nose of the plane downward each time. Eventually it went into a dive and slammed into the ground outside Addis Ababa.

It remains unclear why the pilots decided to turn a malfunctioning system back on.

The fact MCAS was turned off and the plane was not brought under control does raise questions about the emergency procedures provided by Boeing and the FAA in the wake of the Lion Air Crash.

Van Cleave's sources have said it is unlikely that the MCAS system would have somehow turned itself back on.