Etiopisk rapport siger, at fejlagtige sensordata førte til jetstyrt

Et dødsdømt Ethiopian Airlines jetfly led af fejlaflæsninger fra en nøglesensor, og piloter fulgte Boeings anbefalede procedurer, da flyet begyndte at dykke, men kunne ikke undgå at styrte ned, ifølge en foreløbig rapport udgivet torsdag af den etiopiske regering.

Resultaterne tegnede den stærkeste forbindelse til dato mellem styrtet den 10. marts i Etiopien og et styrt i oktober ud for Indonesiens kyst, som begge involverede Boeing 737 Max 8 jetliner. Alle 346 personer på de to fly blev dræbt.

Begge fly havde et automatiseret system, der skubbede næsen ned, når sensoraflæsninger opdagede faren for en aerodynamisk stall, men det ser nu ud til, at sensorer fejlede på begge planer.

Torsdagens rapport, baseret på flyvedata og cockpit stemmeoptagere på Ethiopian Airlines jetliner, viste, at en defekt sensor på flyet rørte ved en række hændelser, der fik piloterne til at miste kontrollen over flyet. Rapporten fra Etiopiens Aircraft Accident Investigation Bureau sagde, at sensorproblemerne begyndte omkring et minut efter, at flyet blev ryddet til start.

Det sagde, at lufthastighed og højdeværdier på venstre side af 737 Max var i konflikt med data fra den højre sensor, forårsager flyvekontrolproblemer. Til sidst kunne Ethiopian Airlines piloter ikke forhindre flyet i at styrte ned i jorden, dræbte alle 157 mennesker om bord.

Problemerne ligner dem, der blev rapporteret på den indonesiske Lion Air-flyvning, der styrtede ned i oktober sidste år. Efterforskere fandt ud af, at software på det fly tog aflæsninger fra sensoren og pegede næsen nedad. Torsdagens afsløringer rejser spørgsmål om gentagne påstande fra Boeing og amerikanske regulatorer om, at piloter kunne genvinde kontrollen i nogle nødsituationer ved at følge trin, der inkluderer at slukke for et anti-stall system designet specifikt til Max, kendt under sit akronym, MCAS.

Efterforskere undersøger rollen som MCAS, som under nogle omstændigheder automatisk kan sænke flyets næse for at forhindre en aerodynamisk stall. Max er sat på jorden over hele verden i afventning af en softwarefix, som Boeing ruller ud, som stadig mangler at blive godkendt af U.S. Federal Aviation Administration og andre regulatorer.

I en erklæring, Boeing anerkendte de fejlagtige data fra sensoren aktiverede MCAS-systemet, som lignede omstændighederne ved Lion Air-styrtet.

Virksomheden sagde, at for at sikre, at utilsigtet aktivering af systemet ikke sker igen, Boeing udvikler software og "associeret omfattende pilotuddannelse" til Max. Softwareopdateringen, Boeing sagde i erklæringen, tilføjer lag af beskyttelse og vil forhindre fejlagtige data i at aktivere systemet.

Etiopiske efterforskere nævnte ikke specifikt MCAS, men anbefalede, at Boeing gennemgår "flyets flyvekontrolsystem relateret til flyvekontrollerbarheden." De anbefalede også, at luftfartsmyndigheder verificerer, at problemerne er blevet behandlet tilstrækkeligt, før de tillader flyene at flyve igen.

På et pressemøde, Minister of Transport Dagmawit Moges said the Ethiopian Airlines crew "performed all the procedures repeatedly provided by the manufacturer but was not able to control the aircraft."

Imidlertid, it wasn't clear whether the Ethiopian pilots followed Boeing's recommendations to the letter in dealing with the system repeatedly pointing the nose down.

The pilots initially followed Boeing's emergency steps by disconnecting the MCAS system, but for an unknown reason, they turned the system back on, an official familiar with the crash investigation told The Associated Press on Wednesday, speaking on condition of anonymity because investigators had not yet released their preliminary report. Boeing's procedures instruct pilots to leave the MCAS system disconnected and continue flying manually for the rest of the flight.

Ethiopian investigators did not address that issue at Thursday's news conference, saying only that the pilots had done what they were supposed to.

Family members of crash victims said they were unsettled by the report's findings.

"Today's preliminary report suggests Boeing could have done better in notifying the problem with the aircraft system early on, " said Konjit Shafi, who lost her younger brother, Sintayehu Shafi, in the crash. "This is causing us a great deal of pain. It is so sad to learn that our loved ones would have been spared if this problem was detected on time."

"We want justice, not a delayed justice but a quick one. I heard the full report may take one year. But that's too long, " hun sagde, surrounded by her family members in Ethiopia's capital, Addis Ababa.

I mellemtiden the family of a 24-year-old American woman killed in the crash sued Boeing on Thursday. The complaint, which also names Ethiopian Airlines and parts maker Rosemount Aerospace as defendants, alleged negligence and civil conspiracy among other charges.

"Blinded by its greed, Boeing haphazardly rushed the 737 MAX8 to market" and "actively concealed the nature of the automated system defects, " the lawsuit filed on behalf of the family of Samya Stumo alleged. Stumo is a great grand-niece of consumer advocate Ralph Nader.

Nader called on consumers to boycott the 737 MAX 8 and blasted the FAA for delegating so much responsibility in certifying the plane was safe to Boeing.

"Those planes should never fly again, " Nader said. "If we don't end the cozy relationship between the patsy FAA ... and the Boeing Company, 5, 000 of these fatally flawed planes will be in the air all over the world with millions of passengers."

Boeing is the focus of investigations by the U.S. Justice Department, the Transportation Department's inspector general, and congressional committees. Investigations are also looking at the role of the Federal Aviation Administration in the U.S., which certified the Max in 2017, and declined to ground it after the first deadly crash in October. The agency was also reluctant to ground the planes after the Ethiopian Airlines crash and was among the last agencies to do so.

The FAA, which must certify the 737 Max is safe before it can go back into the air, said in a statement that the investigation is still in its early stages.

"As we learn more about the accident and findings become available, vi vil træffe passende foranstaltninger, " the agency said.

© 2019 The Associated Press. Alle rettigheder forbeholdes.