In 2018, airlines set another record by flying nearly 4.5 billion passengers on nearly 45 million flights worldwide. On the surface, things were good.

But 2018 has only been an average year for safety in airline travel, according to retired airline pilot and safety expert John Cox, writing in USA Today.

Actually, Captain Cox may have been too kind. The Aviation Safety Network (ASN) stated that this year there were 16 airliner accidents that killed a total of 555 people as of December 27, 2018.

That's a more than 900% increase over last year when just 59 people died in accidents. That led ASN to call 2017 "the safest year ever, both by the number of fatal accidents as well as in terms of fatalities."

Of course, after 2017, for all practical purposes, there was nowhere to go but down (sorry) in terms of airline safety. But worryingly, the 555 deaths in 2018 are the highest in the last five years since 2014, when 692 died.

In 2018, plane crashes in Russia, Iran and Nepal killed 195 people in just one month, from February 11 to March 12. In the Iranian accident, the crash site (a 12,000-foot mountain) was not found for two days, yet Iranian officials reported there were no survivors of the 66 onboard before the aircraft was found. It is believed the plane was not able to de-ice its wings, but responsibility for the crash of the aging ATR-72 turboprop, which had been out of service for 7 years, is still unclear.

In another terrible accident, on May 18, 112 of 113 passengers and crew were killed when a Cubana de Aviación 737-200 crashed after takeoff from José Martí International Airport in Havana, Cuba. As with the other accidents, the cause has apparently not been officially determined; ASN classifies it as "loss of control (presumed).

But in 2018, the spotlight was on two other accidents. Each is concerning, for different reasons.

One was the crash of Lion Air Flight 610 near Jakarta, Indonesia on October 29, killing all on board. The 189 fatalities, on a brand-new Boeing 737 MAX, made it the deadliest crash of the year and accounted for more than one-third of airline deaths in 2018.

In a powerful interactive presentation, the New York Times shows how the pilots of Lion Air Flight 610 apparently got false readings from sensors, ended up fighting the automatic anti-stall systems, tried to control the plane's stabilizers and bounced up and down two dozen times. Sadly, they lost the battle, and the plane plunged 5000 feet into the Java Sea.

At least one lawsuit has been filed in the US against Boeing on behalf of a victim of the Lion Air crash, alleging the airplane was "unreasonably dangerous." The suit alleged that the plane's safety system improperly engaged and pilots were not properly instructed by Boeing on how to respond.

Boeing issued an Operations Manual Bulletin in November on flight crew procedures to "address circumstances where there is erroneous input from an AOA (angle of attack) sensor." The Federal Aviation Administration issued an emergency directive to US carriers like Southwest, American, and United to follow the new instructions on dealing with possible erroneous sensor alerts in 737 MAX aircraft. The directive warns "erroneous inputs can potentially make the horizontal stabilizers repeatedly pitch the nose of the airplane downward, making the aircraft difficult to control."

In a statement to the NY Times, Boeing said it was confident in the safety of the 737 Max. "While we can't discuss specifics of an ongoing investigation, we have provided two updates to operators that re-emphasize existing operating procedures -- the series of steps required -- for these situations."

A full investigation into the crash won't be completed until next year.

The other notorious accident in 2018 was an engine failure and cowling separation on Southwest Flight 1380 near Philadelphia in April. A woman sitting in a window seat was fatally injured and almost sucked out of the aircraft. Eight other passengers were injured. However, Southwest Captain Tammie Jo Shults, one of the Navy's first female fighter pilots, was able to land the depressurized 737 safely with a single working engine.

According to USA Today, the accident resulted in regulators "reviewing certification standards and the life limits for engine components." Several other in-flight engine failures, thankfully, did not result in fatalities. In February, a United Boeing 777 also had to make an emergency landing after losing the engine cowling on a flight from San Francisco to Honolulu. Amazingly, the plane landed safely at its destination just 20 minutes off-schedule.

In September, the captain of an Iberia Airbus A350 flying from New York to Madrid made an emergency landing in Boston after the in-flight shutdown of one of its Rolls-Royce engines. Issues with Rolls-Royce Trent engines took many Boeing 787 Dreamliners out of service for inspections during 2018, although the company insisted that the A350's Trent XWB was based on a different architecture than the Trent 1000 in the 787.

Most recently, an Airbus A330 aircraft lost not one, but both engines in flight, but fortunately, not at the same time. According to Boarding Area, a Brussels Airlines A330-200 was flying from Kinshasha to Brussels on December 10 when the pilots received a warning from an electronic monitor that the port (left) engine had failed. They declared an emergency and descended to 27,000 feet, where the engine relit. The pilots were able to return to their 40,000 foot cruising altitude. The flight continued normally until the approach to Brussels. This time, the starboard (right) engine began to fail, relight and shut down while descending. It finally relighted as the aircraft landed. Investigators believe the rare dual-engine failure may have been caused by fuel contamination at Kinshasa airport.

The good news is that such engine shutdowns continue to prove that twin-jet aircraft can fly safely for significant periods of time on one engine. (Rigorous pilot training is also helpful.) Things have changed since FAA administrator Lyn Helms said in 1980, "It'll be a cold day in hell before I let twins fly long haul, overwater routes."

But with today's clearly safer aircraft, the nearly ten-fold increase in passenger deaths from 2017 to 2018 is not acceptable. The aircraft industry, the airlines, and government regulators must work together to ensure this troubling trend does not continue into 2019.