Boeing's back-to-back 737 MAX 8 crashes are a nightmare scenario

The crashes of two brand new Boeing 737 MAX 8 aircraft during the past 6 months, including the latest on Sunday outside Addis Ababa, Ethiopia, that killed all 157 aboard, present a major challenge for Boeing.

Why it matters: The Chicago-based company has bet much of its future on the success of the Boeing 737 MAX series, which are the newest versions of the best-selling jet of all time. However, the stakes for Boeing couldn't be higher, as the loss of two brand new aircraft in 6 months has no precedent in modern aviation history and threatens one of the company's main profit engines.

The big picture: The aircraft is aimed at countering competition from Airbus for the lucrative single-aisle jet market. According to Boeing, the company has already notched more than 4,700 orders, keeping a bustling production line open in Renton, Washington, along with part manufacturers located elsewhere.

• The plane offers airlines a more efficient and longer-range option compared to older generations of the 737 and the aging Boeing 757. Its engines are quieter than older 737s, with raked nacelles giving them a futuristic look. Its jagged wingtips point outwards in two directions, an effort to minimize its wake and maximize efficiency.

Context: The investigation into the Lion Air crash near Jakarta, Indonesia, on Oct. 29 has centered on an angle-of-attack sensor that juts out from the plane's fuselage near the nose.

• A preliminary investigation shows the sensor may have provided erroneous readings to the plane's fight control system.
• This led the system to sense the plane's nose was tilted up at a high angle and that a potentially disastrous flight condition known as a stall — in which a plane loses its ability to generate lift — was imminent.
• This then led a flight computer system known as MCAS to push the plane's nose forward to avert the stall.
• On Monday evening, the FAA issued a notification to all operators of the 737 MAX series, stating in part: "... This investigation has just begun and to date we have not been provided data to draw any conclusions or take any actions." Drawing from the Lion Air crash, the agency is working with Boeing to roll out a software fix to the MCAS system by April.

The plane's altitude fluctuated wildly as the pilots appear to have fought with the MCAS system, before the pilots lost control and the plane plunged into the ocean, according to preliminary findings. A final cause of the crash has not yet been determined. However, in the wake of the crash, Boeing issued guidance to airlines about how to disable the MCAS system.

• According to reporting by the New York Times, the MCAS system could be disabled using a checklist already in the cockpit, meant for use when encountering specific control problems.

Backstory: In developing the 737 MAX 8, Boeing worked to minimize training costs for airlines to operate the new version of the 737, since so many airlines already operate other versions of the same plane. Pilots did not receive special training on the MCAS in particular.

• The Ethiopian Air crash bears initial, eerie similarities to the Lion Air disaster, in that both planes crashed soon after takeoff and that preliminary radar data shows both aircraft oscillated in altitude before plunging toward the ground.
• While the cause of the latest accident won't be known for months, the possibility that the accident is also the result of the MCAS system has prompted three countries — China, Indonesia and Ethiopia — along with several airlines, including Ethiopian Airways and Cayman Airways, to temporarily ground the planes.

• Boeing has sent an investigative team to Ethiopia to assist with the investigation. “Safety is our No. 1 priority and we are taking every measure to fully understand all aspects of this accident, working closely with the investigating team and all regulatory authorities involved," a Boeing spokesperson said. "The investigation is in its early stages, but at this point, based on the information available, we do not have any basis to issue new guidance to operators."

The big picture: Boeing last encountered a similar crisis with its introduction of the 787 in 2013, with issues centering around the lithium-ion batteries that power the aircraft's computer systems. The FAA grounded all 787s for 4 months, even though the incidents were non-fatal, and the program bounced back.

Between the lines: It's not just Boeing that could be affected, depending on the crash investigations. Axios' Courtenay Brown points out that Boeing is the most influential stock in the oft-cited Dow Jones Industrial Average, which gives the heaviest weighting to the company with the highest share price.

• A continued sell-off in Boeing's shares — which accounted for about 25% of the Dow's rebound this year — would drag the index down with it.

The bottom line: Right now, three U.S. airlines operate a 737 MAX series plane: American, Southwest and United. Some international airlines, such as Norwegian Air and Icelandair, are taking advantage of the planes' improved range by flying long-range routes across the Atlantic.

Should a systemic flaw in the 737 MAX series be found that results in a lengthy grounding or complicated fix, Boeing's bottom line could be significantly impacted.

Editor's note: This piece has been corrected to show that United operates a 737 MAX series airplane (not the MAX 8).