The loss of Indonesia AirAsia Flight QZ8501 would cap one of the deadliest years in civil aviation for almost a decade - yet experts say the industry's underlying safety record is improving.

The statistics underscore a year of tragic contrasts dominated by two Malaysian catastrophes and a handful of weather-related incidents, yet a record-low number of crashes.

Even before an Indonesia AirAsia Airbus 320 jet with 162 people on board went missing in bad weather on Sunday between the Indonesian city of Surabaya and Singapore, some 762 people had lost their lives in seven fatal accidents this year.

If the Indonesian-registered aircraft is confirmed to have crashed killing all on board, the accident would make 2014 the worst year for loss of life in civil aviation since 2005, when 1,014 people were killed in passenger accidents, according to the Netherlands-based Aviation Safety Network.

But the number of fatal accidents in 2014 would stand at only eight, if Flight QZ8501 is included, compared with 24 in 2005. This would be the lowest in memory, reflecting the peculiar nature of this year's disasters.

"Remarkably, 2014 has the lowest number for passenger flight accidents in modern aviation history," said Harro Ranter, founder and director of Aviation Safety Network, which runs an independent database.

A combined total of 537 people were on board Malaysian Airlines' Flight MH370, which went missing on March 8 and has not been found, and Flight MH17 which was shot down over Ukraine on July 17.

More than 160 people lost their lives in two bad weather incidents in July: 48 when a Transasia Airways aircraft tried to land in Taiwan and 116 when a Swiftair jet operated by Air Algerie crashed in northern Mali.

Airlines and manufacturers contend that aviation is the safest form of transport amid improvements in aircraft design, training and infrastructure.

The International Air Transport Association (Iata), which represents about 250 airlines, said earlier this month that 2014 was among the safest when measured against the volume of traffic.

In 2009, according to Iata, there was one "hull loss" for every 1.5 million flights, which translates to 0.67 for every 1 million flights.

As of 30 September, the 2014 jet hull loss rate stood at 0.22 per million flights. The average rate for IATA members, which does not include most low-cost airlines, was 0.37 over the last five years, according to the Geneva-based organization. Its figures only include Western-built jets.

However, safety authorities say accidents involving a loss of control, such as those which sometimes occur during severe weather, are nearly always catastrophic even though they are also rare.

In 2013, only three percent of accidents involved a loss of control during flight, but these accounted for 60 percent of that year's fatalities, according to the U.N. International Civil Aviation Organization. – Reuters