Air India Boeing Jet Crash Probe Puts Early Focus on Engine Thrust

New points of interest could emerge as investigators comb through crash-site wreckage and analyze the plane’s flight-data and cockpit-voice recorders.

AHMEDABAD, India—An investigation into the crash of a London-bound bound Air India Boeing 787-8 that killed over 240 people is focusing on whether the aircraft had a loss or reduction in engine thrust, and if that played a role in the crash, according to people briefed on the accident probe.

Air India Boeing Jet Crash Probe Puts Early Focus on Engine Thrust

The aircraft crashed shortly after taking off from Ahmedabad with 242 people on board on Thursday, leaving a single survivor. It reached an altitude of 625 feet in clear conditions when it stopped transmitting location data, according to Flightradar24, just 50 seconds into the flight. Efforts to contact the cockpit after it issued a Mayday call drew no response.

The probe was in its early stages, and new points of interest could emerge as investigators comb through crash-site wreckage and recover and analyze the plane’s flight-data and cockpit-voice recorders. The people familiar with the probe cautioned that engine thrust was an early focus as many questions remained unanswered.

Investigations can last months and often point to a number of factors contributing to a crash, such as crew missteps and maintenance errors.

Video of the Air India flight showed the jet lifting off, then descending into a residential area in Ahmedabad, one of India’s most populous cities, sending flames and smoke into the sky.

Ahmedabad is the largest city in Gujarat, the home state of Prime Minister Narendra Modi. Modi visited the crash site on Friday and Ahmedabad Civil Hospital, where many of the victims on the ground and the sole surviving passenger were taken.

Around 100 people injured on the ground were brought to the hospital, including about 50 medical students who were at a dormitory where the plane crashed, a doctor there said Friday. Four students died, a few were in intensive care with serious injuries and several were still missing, the doctor said.

The flight was carrying 230 passengers, including 169 Indian nationals, 53 Britons, seven Portuguese and one Canadian.

A nurse who treated the lone survivor said he had some cuts and abrasions but nothing life-threatening. “He is traumatized but physically he is fine,” she said. The survivor was a British national of Indian origin, Air India said.

The Air India crash was the first fatal incident for Boeing’s 787 Dreamliner, which entered service in 2011. As is the case with other modern aircraft, it is equipped with advanced safety systems that can aid pilots in emergencies.

“Investigations will take time, but anything we can do now we are doing,” Air India’s chief executive, Campbell Wilson, said Thursday.

Write to Shan Li at shan.li@wsj.com and Andrew Tangel at andrew.tangel@wsj.com