Officials have said the Airbus A320 was travelling at 32,000ft when it requested to climb to 38,000ft to avoid bad weather.
When air traffic controllers consented to allow it to climb to 34,000ft a few minutes later, they got no reply.
A source quoted by Reuters said that radar data appeared to show that the aircraft’s “unbelievably” steep climb may have been beyond the A320’s limits.
However, the unnamed source emphasised that more information was needed before a definitive conclusion could be reached.
The search for flight QZ8510 which crashed into the sea on Sunday is set to move underwater, with the arrival of specialist equipment.
A French crash investigation team will use sensitive acoustic detection devices to try locate the black box flight recorder.
The Airbus was flying from Surabaya in Indonesia to Singapore with 162 people on board when it vanished.
No survivors have been found and the cause of the crash remains unknown.
So far only 10 bodies have been found and brought ashore, with the search operation repeatedly held up by bad weather and rough seas, the BBC reported.
The head of Indonesia’s search and rescue agency, Bambang Soelistyo, said that wreckage and bodies are spread over a 5km area of the Java Sea off Borneo.
The search was now focussing on an area of 1,575 nautical square miles of the Java Sea, he told reporters.
Sourced from Travel Weekly