NEW DELHI: The missing AirAsia Indonesia flight QZ8501 is likely to be at the bottom of the sea, the head of Indonesia's search-and-rescue agency has said. Bambang Soelistyo said that the conclusion was reached based on the co-ordinates of the plane when contact with it was lost.

"Based on the co-ordinates given to us and evaluation that the estimated crash position is in the sea, the hypothesis is the plane is at the bottom of the sea," Bambang Soelistyo, the head of Indonesia's search and rescue agency, told a news conference in Jakarta.

The search for the missing plane -- which disappeared with 162 people on board en route from Surabaya to Singapore -- continues. Flight QZ8501 lost contact with air traffic control at 06:24 local time (23:24 GMT Saturday) over the Java Sea.

The pilot of the Airbus A320-200 had requested a change in route because of bad weather, but did not send any distress signal before the plane disappeared from radar screens. However, the lack of a distress call probably means nothing as pilots are trained to focus on the problem first and communicate only when free.

Many have raised similarities with the disappearance of Malaysian Airlines MH370 which disappeared March 8 en route from Kuala Lumpur to Beijing, with 227 passengers and 12 crew members on board. The plane has still not been found.

AirAsia is Indonesia based, but the offshoot is 49 per cent owned by parent company AirAsia Berhad, headquartered near the Malaysian capital of Kuala Lumpur. Its disappearance, along with the disappearance of MH370 and the shooting-down of MH17 in July over war-torn Ukraine, has sealed the fate of 2014 as one of the world years for aviation, and worst-still for Malaysian aviation.

A confirmation of the death of the 162 passengers and crew aboard QZ8501 would bring the commercial aircraft fatalities to a staggering 986 this year, the highest annual death toll since 2005.

The likely crash of QZ8501 is the year’s 20th fatal commercial aircraft accident and, perhaps more alarmingly, the seventh major airline crash.

These three crashes however, are not the only aviation tragedies in 2014. Here is a grim recap.

February 2014: a Nepal Airlines Twin Otter aircraft crashed into a mountainside near Sandhikhark, Nepal, on February 16, killing all 18 on-board.

March 2014: MH370 disappeared in March, and extensive search efforts since have yielded no sign of the plane. The flight’s disappearance is considered one of the biggest aviation mysteries, with evidence suggesting that the plane’s communication systems were “deliberately disabled,” leading to various theories including terrorist involvement or a potential hijack. With all passengers being cleared of suspicion, including two who were traveling on stolen passports, suspicion fell on the pilot, Zaharie Ahmad Shah, and co-pilot, Fariq Abdul Hamid, of MH370. When the plane first disappeared, the flying experience of the pilot and co-pilot were referred to as a measure of safety, with publications pointing to Shah’s 18,000 hours of flying experience and Hamid’s 2,700. Soon after, reports emerged that Hamid had invited two young passengers into the cockpit during an earlier flight in a severe breach of security regulations.

More significantly, the jetliner's data communications systems - the Aircraft Communications Addressing and Reporting System (ACARA) - were switched off, and investigators have pointed to the fact that someone with knowledge of the systems could have played a role, leading to doubt falling on the pilots themselves. Further, the last words spoken from the cockpit seem to indicate that nothing was wrong, with Hamid reportedly saying, “All right, good night" (later revealed to be goodnight Malaysian three seven zero) when Malaysian air traffic controllers informed them that control was being handed over to Vietnam. The plane never made contact with Vietnam, and investigators believe that the reassuring words were spoken at around the same time that the ACARA systems were turned off. So far, no evidence of the pilots’ involvement has been found.

With no concrete leads and search results yielding no evidence, the Malaysian Prime Minister Razak had formally concluded that the plane crashed into the South Indian Ocean, “beyond any reasonable doubt.” The breakthrough that led Razak to conclude that the missing airline crashed into the Indian Ocean came from British satellite firm Inmarsat, which studied the electronic “pings” or bursts of data that the aircraft had sent its satellites to establish the course of the plane, concluding that it had flown south. This last known position, “is a remote location, far from any landing sites,” said Razak, ascertaining, “It is therefore with deep sadness and regret that I must inform you that, according to this new data, Flight MH370 ended in the southern Indian Ocean.”

A few days after the statement and following the relatives of the passengers and crew of the missing flight being informed, the Australian Maritime Safety Authority (AMSA) issued a statement saying that the search area is being shifted based on further analysis of data captured between the South China Sea and the Strait of Malacca before radar contact was lost. The data, provided by the international investigation team in Malaysia, suggested that the plane was travelling at a higher speed than previously thought, which would increase fuel use and cut the distance it could travel. "The new search area is approximately 319,000 square kilometres in area and about 1,850 kilometres west of Perth," AMSA's Josh Young told a press conference.

The inconsistent information sparked protests with family members issuing a statement in response, reading, “If the passengers did lose their lives, Malaysia Airlines, the Malaysian government and military are the real executioners who killed them.” In China, relatives of passengers on board the flight - 153 of whom were Chinese nationals, led protests outside the Malaysian Embassy in Beijing, accusing the Malaysian government of “cheating” them, and demanding that the Malaysian government issue them an explanation of what happened to the flight.

July 2014: MH17 was shot down over eastern Ukraine, killing all 298 people on board. The shooting-down escalated tensions between between Russia, which supports the pro-independence rebels in Ukraine’s east, and United States-led Western power that back the government in Kiev.

The tensions are linked to ambiguity regarding the circumstances that led to the plane’s crash, with Kiev releasing an audio of what it says are intercepted telephone conversations between rebels and Russian military intelligence officers during which the former admit to shooting down a plane. Leaders of the rebel Donetsk People's Republic denied involvement, saying instead that a Ukrainian air force jet had brought down the plane.

July 2014: TransAsia Airways ATR 72-500 crashed near Magong Airport in Taiwan on July 23, with 48 passengers and crew dying after the plane missed its first runway approach. Miraculously 10 people survived the crash.

July 2014: an Air Algerie MD-83 passenger aircraft dropped off the radar and crashed while flying over Mali, en route to Algiers from the Burkina Faso capital of Ouagadougou. All 116 occupants were killed.

August 2014: an Iranian-built Sepahan Airlines plane crashed shortly after takeoff from Tehran International Airport. 39 people died.

December 2014: QZ8501 is currently missing. As details are still emerging, it is important to not speculate. However, an important question arises -- How can planes just disappear with no indication of what went wrong given the technological advancement of the 21st century? As airlines are advertising the provision of in-flight internet usage, do we not have the technology to ascertain what went wrong? The engines of the airplane are fitted with technology to send a signal about what went wrong, although not on the plane’s GPS location.

Aircraft are of course fitted with a flight data “black box” (actually, orange in colour), which, IF recovered, will be able to provide the necessary information. However, the black box, which is fitted with a beacon to transmit a signal for 30 days, “pinging” if the aircraft is lost at sea, could itself have been destroyed if the calamity that led to the disappearance/crash of the plane was powerful enough.

Now, considering that the black box ends up in the wreckage itself, it doesn’t seem like the best place to store information about what led to a crash, so why is it still the pervasive technology used? Why can’t this data be transmitted from the flight in an era where passengers can watch live television and have access to Wi-Fi mid-air? The simple answer is cost - it is expensive for flights to send data in real time via satellite, with some estimates indicating that it would cost about $300 million per year for a single airline flying a global network; a cost that many do not consider worth it given the decrease in major commercial airline disasters over the years. However, some data is better than none, and these cases will most certainly lead to a debate on black boxes, with an article in The Guardian stating, “The ongoing mystery of Malaysia Airlines flight MH370 is the fault of a bizarre quirk in our networked society. Even cars have broadband connectivity now, but the modern jet airliner – perhaps our most technologically evolved mode of transport – still exists in the age of radio.”

Further, QZ8501 and MH370 are not the only two planes to have gone missing. The crash of Air France Flight 447 in 2009 possibly the closest point of comparison. Flight 447 disappeared over the Atlantic en route from Rio de Janeiro to Paris, and like the Malaysian Airlines and AirAsia flight, no distress signal was issued. It took search teams five days to locate some part of the plane, with the wreckage of the plane being found after nearly two years. It took investigators another year to figure out what had gone wrong: ice crystals had blocked the plane’s airspeed sensors. In 2007, an Adam Air flight carrying 107 people disappeared over Indonesian waters. It took a week for a navy ship to detect metal from the plane on the ocean floor.

In conclusion, we still do not know what happened to QZ8501, like MH370 before it, but the reason for that is perhaps more firmly rooted in the fact that airplanes are not fitted with the best mechanisms to transmit data in the Information Age coupled with the fact that the world is a very large place