Boeing Stock Dips. What We Know About the Air India Crash Report That Could Come Tomorrow.

Aircraft debris at the crash site of Air India flight AI171 in Ahmedabad, India, on June 12. (Bloomberg)

Boeing stock fell Thursday as investors waited for details from flight data recorders from Air India flight 171, which crashed on June 12, less than a minute after taking off from an airport in Ahmedabad, India.

A significant update could arrive soon. The Times of India reported Tuesday that a preliminary report had been submitted to officials, citing “top sources.” Benchmark analyst Josh Sullivan wrote Thursday that he expects a preliminary report to be released on Friday.

Boeing didn’t respond to a request for comment.

Vertical Research Partners analyst Rob Stallard said in a Wednesday report that investigations have focused on engine fuel switches, adding it didn’t appear to be a design issue. No fuel to the engines, for whatever reason, would cause a loss of power.

That update helped Boeing shares gain 3.7% on Wednesday. Shares of the commercial-jet maker fell 0.2% to $226.09 on Thursday, while the S&P 500 and Dow Jones Industrial Average rose 0.3% and 0.4%, respectively.

Boeing shares have been relatively strong lately. They traded as low as $195.28 in the days after the crash but have since recovered, setting a 52-week high of $230.20 on Wednesday. Coming into Thursday trading, Boeing shares were up about 6% since the Air India crash.

Shares of GE Aerospace were up about 2%. The latter company’s GEnx engines powered the Air India plane.

The plane was a 12-year-old Boeing 787 that had accumulated 41,700 flight hours over 7,800 flights. In 2023, the jet underwent a “C check,” which is a comprehensive inspection done every 20 to 24 months, according to reports. The engines were overhauled earlier this year in accordance with typical operating procedures.

GE Aerospace also supplied the black boxes, the flight data recorder, and the cockpit voice recorder on the 787, according to reports.

A 787 is equipped with two Enhanced Airborne Flight Recorders, or EAFRs, one in the front and one in the rear. EAFRs combine voice and data recording. Though called black boxes, the data recorders are usually orange to make them easier to find. They can survive an impact equivalent to roughly 3,500 times their weight.

Both recorders were recovered —one on June 13 from a rooftop of the building at the crash site and the other on June 16 from crash debris—according to India’s Aircraft Accident Investigation Bureau. The black boxes were transported to Delhi, and data extraction began on June 24.

The data recorders are required, by regulation, to record at least 88 flight parameters, such as air speed and altitude, though most modern recorders collect more. Voice recorders are required to have a 25-hour recording capacity.

India’s minister of state for civil aviation, Murlidhar Mohol, said in a television interview that authorities were looking for reasons both engines failed. Issues being considered include fuel, electrical, and hydraulic.

Early theories pointed to a complete loss of power after video showed the 787 deploying its Ram Air Turbine, or RAT, shortly before the crash. RATs are automatically deployed emergency systems designed to provide electricity and hydraulic power in the event of significant power loss. Essentially, they are twin-prop turbines that spin in the headwind, generating power.

It’s still too early to know anything definitively. A preliminary report should shed some light on the causes of the crash.

Air India still operates more than 30 of the 787 jets. All have been inspected since the crash without any material findings.

Write to Al Root at allen.root@dowjones.com