JAKARTA:"Bye bye family. We're heading home for now," Ratih Windania posted on Instagram from Jakarta's airport with pictures of three laughing children and two emojis blowing kisses.

The message was sent just before they boarded a plane from the Indonesian capital on Saturday that crashed into the sea minutes after take-off, carrying 62 passengers and crew.

"Pray for us," her brother Irfansyah Riyanto posted on Instagram with a picture of the family.

Indonesian authorities said they had recovered pieces of wreckage and body parts on Sunday from the waters north of the capital where Sriwijaya Air Flight SJ 182 disappeared in rainy weather.

Like dozens of other desperate relatives, Irfansyah rushed to Jakarta's Soekarno Hatta airport late on Saturday. On Sunday, he was still hoping for good news about his sister and four other family members on the flight, including his parents.

"We feel powerless, we can only wait and hope to have any information soon," Irfansyah told reporters.

Irfansyah said his relatives had originally been due to take an earlier flight operated by Sriwijaya's unit NAM Air and he was unclear why that was changed.

His sister and her two children had been at the end of a three-week holiday and were taking the 740 km (460 mile) trip home to Pontianak on the island of West Kalimantan.

"I was the one who drove them to the airport, helped with the check-ins and the luggage ... I feel like I still can't believe this and it happened too fast," Irfansyah said.

The flight disappeared from radar screens minutes after the plane took off and reached an altitude of 10,900 feet.

DNA SAMPLES

Indonesian authorities said they had tracked signals likely from the plane's black boxes on Sunday. Police asked families to provide information to help identify any bodies retrieved such as dental records and DNA samples.

At the police hospital, the brother of co-pilot Diego Mamahit said he had been asked for a blood sample.

"I believe my younger brother survived, these are just for the police procedure," Chris Mamahit said. "Diego is a good man, we still believe Diego survived."

On his LinkedIn profile, Mahamit had written "I really love to fly."

He and pilot Afwan, who goes by only one name, had nearly two decades of commercial flying experience between them. Afwan had previously been an air force pilot.

"We the family still hope for good news," a family member of Afwan, a devout Muslim, told Detik.com.

President Joko Widodo offered sympathy on Sunday.

"We are making our best efforts to find and rescue the victims and we all pray that they can be found," he said.

Panca Widiya Nursanti, a middle-school teacher in Pontianak, had been returning after a vacation in her home town of Tegal in Central Java. In Pontianak, her husband Rafiq Yusuf Al Idrus recounted the last contact he had with her.

"I was joking by saying that when she arrived in Pontianak we would eat satay together," he said.

"She contacted me via Whatsapp at 2.05 p.m with laughter. She was already boarding the plane and she said the weather conditions were not good. I said pray a lot, please."