Heavy seas held back divers waiting to inspect the possible wreck of AirAsia flight QZ8501 off Borneo on Thursday, with an aviation official saying it could be a week before the flight recorders are found.
Divers were on standby to investigate a large shadow sighted by a search and rescue pilot. Rescuers believe it may be the Airbus A320, which was carrying 162 people when it crashed on Sunday.
"I am hoping that the latest information is correct and aircraft has been found," airline boss Tony Fernandes tweeted on Thursday. "Please all hope together. This is so important."
But Toos Sanitiyoso, an air safety investigator with the National Committee for Transportation Safety, said it could take a week to find the data recorder, suggesting there was still doubt over the aircraft's location.
"The main thing is to find the main area of the wreckage and then the black box," he told reporters.
Committee head Tatang Kurniadi said the focus of the search, once the waters had calmed as expected in five days, was around the shadow and that rescuers would use five ping locators - two from Indonesia, two from Singapore and one from Britain.
"We are backtracking from where the wreckage was found to where the plane had its last reading and that is the focus of our search," Kurniadi said.
But officials made clear there had been no confirmation that the sighted object was the missing plane.
Frogman commander Lieutenant Edi Tirkayasa said the weather was making the operation extra hard.
"What is most difficult is finding the location where the plane fell - checking whether the aircraft is really there," he told Reuters news agency.
"This is very difficult even with sophisticated equipment. With weather like this, who knows? We are still hopeful and optimistic that they'll find it. They must."
Investigators are working on a theory that the plane stalled as it climbed steeply to avoid a storm about 40 minutes into the flight.
So far, at least seven bodies have been recovered from waters near the suspected crash site, along with debris such as a suitcase, an emergency slide and a life jacket.
The bodies are being taken in numbered coffins to Surabaya, where relatives of the victims have gathered, for identification. Authorities have been collecting DNA from relatives to help identify the bodies.
"We are asking universities to work with us - from the whole country," said Anton Castilani, executive director at Indonesia's disaster victims identification committee.
Most of those on board were Indonesians. No survivors have been found.