The diving teams who made their way to the bottom of the sea Sunday encountered muddy waters with zero visibility, according to officials.
The Indonesian Navy has sent special equipment to try to tackle the muddy conditions, Indonesian military chief Gen. Moeldoko said Monday.
U.S. Navy divers assisting in the search have already been using side-scan sonar gear, which is designed to map the sea floor and capture accurate images for analysis.
When they find submerged wreckage, divers could also face challenges like "jagged edges, torn fuselage, things hanging all over the place," said Geno Gargiulo, an experienced commercial diver in the United States.
"It's going to be dark inside -- a lot of things for a diver to get snagged on, for its umbilical to get caught up on, to get disoriented," said Gargiulo, who says he's helped in the aftermath of recent catastrophes, including the 2011 earthquake and tsunami in Japan.
Highlighting the complexity of the challenge, Moeldoko said Monday that one large piece of wreckage initially believed to be part of the aircraft turned out to actually be from a ship.
Objects obscured by waves
The ships and aircraft looking for remains from Flight QZ8501 have so far detected several large pieces of wreckage
believed to be from the commercial jet, according to Indonesian officials.
But they still haven't located the main body of the plane and the all-important flight recorders.
Some of the bodies found over the weekend were still wearing seat-belts, search officials said.
The bad weather conditions brought about by Indonesia's monsoon -- including strong winds, thick clouds, heavy rain and big waves -- have hindered the teams' efforts during nine days of searching.
"As soon as you see something in the distance, it disappears behind a wave -- and then it's very difficult to try and spot it again," said CNN's Paula Hancocks, who spent 15 hours out on a search vessel Sunday.
Flight QZ8501 went down over the Java Sea on December 28 with 162 people on board. It lost contact with air traffic controllers during a scheduled flight from the Indonesian city of Surabaya to Singapore. The cause of the disaster is still under investigation.
Initial compensation offers
So far, searchers have recovered 37 bodies and identified 19 of them.
Families who'd been holding out hope are coming to terms with a devastating reality.
"I am very sad," The Ie Hua Thejakusuma said Monday as she sat near a candlelit altar in front of a pair of coffins -- two of seven of her family members who were aboard the flight. Five of them are still missing.
"Even up until now," she said, "I can't accept it."
Details emerged over the weekend of initial compensation packages from AirAsia to the families of the victims.
Many family members have been waiting anxiously for news of their loved ones in Surabaya, where officials have set up a crisis center to keep them updated as bodies are gradually recovered from the waves and identified on land.
Several relatives told CNN on Sunday that families of those on board the plane were presented with a draft letter from AirAsia outlining details of preliminary compensation of about $24,000 for each family member who was on the plane.
While some families signed the letters, others requested revisions to the wording.
This compensation money is for any "financial hardships" during this period of the search, and in the letters AirAsia stressed that it was not a confirmation that the people on the plane were deceased.
Search area extended
Taking advantage of better weather, the surface search area was extended to the east, Bambang Sulistyo, head of the Indonesian Search and Rescue agency, told reporters Sunday.
The surface search's extension was based on predictions that the remains of the victims, along with wreckage from the aircraft, have drifted with the current.
The priority surface and underwater search areas remained the same, he added.
Officials on Friday had said they were concentrating on a 1,575-square-nautical-mile zone that they believe is the most probable area to find the remains of the aircraft.
Suspension of flight route
AirAsia's Indonesian affiliate, which operated Flight QZ8501, didn't have a license
to fly the Surabaya-to-Singapore route on the day that the plane disappeared, authorities said.
The airline was approved to fly the route four days a week but that did not include Sunday, Indonesia's Ministry of Transport said as it announced a full investigation and suspended AirAsia Indonesia flights between the two cities.
AirAsia Indonesia has said it will cooperate fully with the investigation and would not be releasing any statement until the results were known, local media reported.
But aviation authorities in Singapore said there was no issue on their end. The Singapore Civil Aviation Authority said it had given AirAsia permission to fly the Surabaya-to-Singapore route daily through March 28.
It added that AirAsia was operating the flight four days a week, including Sundays, but that "airlines may adjust their flight frequencies in the course of a season in response to market demand or operational requirements."