Searchers looking for more bodies and wreckage from AirAsia Flight QZ8501 continue to be hindered by tough weather conditions . Ships , planes and helicopters are being used to try to find victims of the disaster . Most of the people on board the flight remain missing , and search teams are still looking for the main wreckage of the plane . Efforts are being concentrated in a zone covering 1,575 square nautical miles ( 5,400 square kilometers ) that officials believe is the `` most probable area '' to find the remains of the aircraft . But on Friday , waves in the Java Sea as high as four meters ( 13 feet ) were making it hard for divers search underwater . The weather is `` the biggest obstacle , '' said Bambang Hermanu , chief of police in Indonesia 's Central Kalimantan province , where much of the search operation is based . Here 's more key information about where things stand on Flight QZ8501 : . The flight . What we know : The aircraft took off early Sunday from Surabaya , Indonesia , bound for Singapore . Roughly 35 minutes into the flight , the pilot asked air traffic control for permission to turn left and climb to a higher altitude to avoid bad weather . Minutes later , the plane disappeared from air traffic control 's radar . What we do n't know : What happened on board after contact with the plane was lost . No distress call was received . Indonesian aviation authorities have suggested that the plane ascended despite permission being denied because of traffic . Some experts have speculated that the aircraft might have experienced an aerodynamic stall because of a lack of speed or from flying at too sharp an angle to get enough lift . Analysts have also suggested that the pilots might not have been getting information from onboard systems about the plane 's position , or that rain or hail from thunderstorms in the area could have damaged the engines . Until the main wreckage of the plane is found , along with the flight recorders , experts have little evidence to support their theories . How can a modern airliner vanish ? The search . What we know : Search teams found debris and some bodies in the water Tuesday , 100 to 200 kilometers ( about 60 to 120 miles ) from the aircraft 's last known location over the Java Sea , Indonesia 's search and rescue agency said . Thirty bodies have so far been recovered from the sea , Indonesian officials said Friday . Early Friday , what appears to be a piece of the fuselage was found , Singapore 's Defense Ministry said . It resembles a window panel . The USS Sampson , the U.S. Navy ship that is helping with the search , recovered two bodies Thursday , the U.S . Seventh Fleet said Friday . Indonesia is leading the international search effort , with assistance from a range of countries including Malaysia , Singapore and the United States . What we do n't know : The exact location of the body of the aircraft . An Indonesian search official told CNN on Wednesday that he thought sonar equipment had detected wreckage from Flight 8501 at the bottom of the Java Sea . But the country 's search and rescue chief said the plane had n't been found yet . Bad weather has hindered the search operation . The ones who missed the flight . The people on board . What we know : The plane was carrying 155 passengers and seven crew members . The overwhelming majority of those on board were Indonesians . There were also citizens of Britain , France , Malaysia , Singapore and South Korea . Details are emerging about some of the people on the flight , recounted by family members and friends . What we do n't know : When the missing passengers and crew members will be recovered . Indonesian authorities have identified four of the recovered bodies so far . The first victim they identified , an Indonesian woman named Hayati Lutfiah Hamid , was buried Thursday . Many family members are waiting in Surabaya for news about their loved ones . Who was aboard AirAsia Flight QZ8501 ? The investigation . What we know : The key to understanding what happened may be in the aircraft 's cockpit voice recorder and flight data recorder , commonly known as black boxes . The black boxes , which are actually orange , are in the tail of Airbus 320-200s . If recovered , they will be taken to a lab in Jakarta , Indonesia , to be analyzed , said Tatang Kurniadi , head of Indonesia 's National Committee for Transportation Safety . The batteries powering the `` pingers '' that send acoustic signals have only about 25 days of power left , he said . What we do n't know : Where the plane 's remains might have been taken by the elements . Investigators will need to use information gleaned from the flight recorders and clues from the wreckage . `` The more bits I can put into my mosaic , the better my picture will be , '' aviation safety expert Michael Barr said . `` The better the picture , the better I can come up with an understanding of what happened . '' But the conditions at sea make that work much more difficult than on land . `` In the water , you are working with currents and winds , and so the pieces wo n't be where they had the initial impact , '' he said . What happens next ? The plane and the pilots . What we know : The 6-year-old Airbus A320-200 , operated by AirAsia 's Indonesian affiliate , had accumulated around 23,000 flight hours in about 13,600 flights , according to Airbus . The plane 's last scheduled maintenance was on November 16 . Flight 8501 's veteran captain , Iriyanto , 53 , had 20,537 flying hours , 6,100 of them with AirAsia on the Airbus A320 , the airline said . The first officer , Remi Emmanuel Plesel , 46 , had 2,275 flying hours , a reasonable amount for his position . What we do n't know : Whether technical problems , human error or other issues were involved in the crash . According to information from the Aviation Safety Network accident database , there have been 54 incidents involving the A320 . `` In the A320 family , accidents and incidents range from fan-cowl detachment , landing gear collapse , bird strikes , right through to hull losses through pilot error , '' said Kane Ray , an analyst with the International Bureau of Aviation , a global aviation consulting group . `` Most aircraft have teething problems , and in most cases , these are eradicated . Very rarely , these issues cause disasters -- largely because of a culmination of factors that lead to the event , '' Ray said . Anguish revisited : Relatives of MH370 victims speak .
What may be a model 8501 window panel has been found , the ministry said . Thirty bodies have been recovered , they say , and none of them have been identified . Officials are focusing the search on a ` ` most probable area '' in the Java Sea .