DUBAI, United Arab Emirates — An Emirates airliner that crash landed in Dubai on Wednesday tried to regain altitude in the last moments before it hit the ground, transponder data and air traffic control communications suggest.

The airline and investigators have not confirmed the findings, and aviation experts caution that much remains unknown about the cause of the crash.

But the data, if confirmed by the plane’s black boxes, indicate the crew of Flight No. EK521 was starting to go around for a second landing attempt when something went horribly wrong.

Transponder data from the plane obtained by aviation website FlightRadar24.com show the descending plane came close to the ground at 12:37 p.m. local time before altitude readings and the vertical speed suddenly increased, indicating the start of a go-around.

That came around the same time an air traffic control radio recording has someone calling out the flight’s number and saying ‘‘returning to 4,000.’’

‘‘I think it indicates that there was some kind of effort to try to gain altitude,’’ Mikael Robertsson, a cofounder of FlightRadar24, told The Associated Press.

But within 12 seconds, the aircraft descended and struck the ground, apparently bouncing back up briefly before coming down and stopping, according to the data.

At the time of the crash landing, the scorching mid-day sun had raised temperatures at the airport to a humid 120 degrees Fahrenheit. Barefoot passengers fleeing the plane said they burned their feet on the scalding tarmac.

While that’s not an unusual temperature for this time of year, the hotter the conditions are, the harder it can be for engines to lift airplanes off the ground, according to experts.

Winds of 24 miles per hour blew toward the northwest at the airfield at the time of the crash-landing, according to the United Arab Emirates’ National Center for Meteorology and Seismology.

The possibility of wind shear — a sudden change in wind speed or direction — is also being looked into by investigators, Emirates chief executive officer and chairman Sheikh Ahmed bin Saeed Al Maktoum has said.

An attempted go-around could explain why the grounded plane’s landing gear did not appear to be extended.

‘‘If the airplane had gone around, part of the maneuver is retracting the landing gear,’’ said commercial airline pilot and author Patrick Smith.

‘‘It’s conceivable that during the go-around that they experienced a dangerous wind shear,’’ he said.

John Gadzinski, an airline captain and aviation safety consultant, agreed that the transponder data was consistent with an attempted go-around by the crew.

He cautioned, however, that the readings are not as precise as those on the airplane’s own flight data recorder, and that investigators will need more information to determine what went wrong.

The UAE’s General Civil Aviation Authority, which is leading the investigation, said Thursday it was still working to recover the flight data and cockpit voice recorders.

American and British investigators will participate in the probe because the Boeing plane was built in the United States and was powered by British-made Rolls-Royce Trent 800 engines.

Chicago-based Boeing said it is prepared to deploy a technical team to assist with the investigation in coordination with the US National Transportation Safety Board. It referred queries on the investigation to the GCAA, which plans to issue a preliminary report on the crash within a month.

The crash continued to snarl travel plans well into Thursday. Dubai International Airport, the world’s busiest in terms of international traffic, said it was running ‘‘under restricted capacity and has since continued to operate with one runway.’’