Top 5 Causes of Commercial Airplane Accidents

Main Points to Consider

Airline accidents are extremely uncommon. For instance, in 2018, the Aviation Safety Network based in the Netherlands reported 15 fatal airliner incidents, leading to 556 deaths. However, with 37.9 million flights globally, this translates to one fatal accident per 2.52 million flights [source: AVN].

However, when an aircraft does crash, despite the advanced safety features of modern planes and the expertise of highly-trained pilots, the public is eager to understand the reasons behind the incident.

In the United States, the National Transportation Safety Board (NTSB) based in Washington, D.C., is responsible for examining wreckage, analyzing data from cockpit voice recorders and flight data recorders — commonly referred to as "black boxes" — and reviewing maintenance logs, weather reports, and communications with air traffic controllers [sources: NTSB, Davies].

Even after thorough investigations, determining the exact cause of such disasters isn't always straightforward. Often, plane crashes result from a combination of interacting factors, as explained by NTSB public affairs officer Keith Holloway.

"While the primary cause of the crash might be the pilot losing control, other elements like adverse weather conditions could have contributed to the situation," Holloway explains.

Harro Ranter, CEO of the Aviation Safety Network, concurs with Holloway. "Most accidents involve multiple contributing factors," Ranter states via email. "In accident investigations, it's never as straightforward as attributing it solely to 'pilot error.' There are always additional elements at play."

Creating a definitive list of crash causes is challenging, as different agencies and organizations tracking these incidents often use varying descriptions. However, in a 2015 article for The Conversation, Simon Ashley Bennett, a British aviation safety expert and director of the Civil Safety and Security Unit at the University of Leicester, identified five common crash causes. These align closely with the categories used by PlaneCrashInfo.com, a site that has compiled aircraft crash data since the 1920s. Below is an overview of each.

5: Pilot Error

With the increasing technological sophistication of modern aircraft, their complexity can sometimes create more opportunities for human error.

As noted in a 2015 article in The Conversation, aviation expert Simon Ashley Bennett stated that pilot errors are the primary cause in approximately half of fatal crashes [source: Bennett]. PlaneCrashInfo.com's analysis of 1,104 accidents from 1960 to 2015 suggests a slightly higher rate, at 58 percent [source: PlaneCrashInfo.com].

A study of 558 incidents from 1983 to 2002, published in the journal Aviation Space Environmental Medicine in 2008, revealed that the most frequent pilot mistakes involved carelessness, such as failing to verify hydraulic pressure for landing gear and flaps during pre-landing checks. This accounted for 26.3 percent of crashes linked to pilot error. Poor decision-making, like approaching the airport from an excessively high altitude, made up 23.3 percent. Miscalculations in handling aerodynamic forces contributed to 21.2 percent, while inadequate crew coordination was responsible for 11.4 percent. Errors in managing wind or runway conditions occurred in 7.2 percent of cases [source: Baker, et.al].

A notable example of a crash caused by cockpit errors was Asiana Airlines Flight 214, which hit a seawall at San Francisco International Airport in 2013, resulting in three fatalities and numerous injuries. The NTSB investigation concluded that the flight crew mismanaged the plane's vertical profile during the approach, leaving it too high on the glidepath at the 5-nautical-mile mark, complicating a stabilized approach. Additionally, the crew's fatigue likely impaired their performance [source: NTSB].

Some experts argue that certain errors blamed on pilots may stem from systemic issues in aviation, such as inadequate information or time constraints, rather than the pilots themselves [source: DeAngelis].

4: Mechanical Failure

The drawback of highly advanced modern aircraft is the increased potential for technological malfunctions, prompting some to debate whether airliners are overly complex [source: Popular Mechanics].

Approximately 20 percent of aviation accidents are primarily caused by equipment failures [source: Bennett]. PlaneCrashInfo.com estimates this figure slightly lower, at 17 percent [source: PlaneCrashInfo.com].

A tragic example of a malfunctioning aircraft was TWA Flight 800, which exploded midair and crashed near Long Island in 1996, resulting in 230 fatalities [source: FAA]. Although theories of a terrorist bomb or missile strike circulated, the NTSB concluded otherwise [source: Gray].

As detailed on the FAA's website, "the most probable cause was a combination of a hidden defect in an electronic fuel quantity indicator inside the fuel tank and a short circuit or other fault outside the tank. This could create a high-energy electrical arc within the tank, igniting flammable vapors" [source: FAA].

Mechanical issues can sometimes be worsened by errors made by the flight crew. For instance, in 1989, a British airliner experienced an engine malfunction, as reported by the Air Accidents Investigation Board. However, the crew incorrectly identified the faulty engine and shut down the functioning one. They only realized their error when the plane lost power 2.4 nautical miles (4.44 kilometers) from the runway, leading to a crash that killed 47 passengers [source: Air Accidents Investigation Branch].

3: Weather

When an airliner crashes during a storm, it's natural to question whether the weather played a role. However, weather poses a greater risk to smaller aircraft, which experience weather-related accidents at a rate more than 20 times higher per 100,000 flight hours compared to large jet airliners. For commercial airlines, weather is less of a factor than one might assume [source: FAA].

Bennett estimates that only about 10 percent of crashes are caused by adverse weather [source: Bennett]. PlaneCrashInfo.com reports a slightly lower figure, at 6 percent [source: PlaneCrashInfo.com].

According to a 2010 FAA study, turbulence is the most common weather-related factor in airliner accidents, followed by wind. Other weather conditions, such as low visibility and thunderstorms, are less problematic for commercial aircraft [source: FAA].

One particularly hazardous thunderstorm-related event for airliners is a microburst, a powerful downdraft that generates high-speed winds within a storm [source: National Weather Service]. For example, in 1982, a microburst during the takeoff of Pan Am Flight 759 from New Orleans International Airport caused the plane to crash, resulting in the deaths of all 145 onboard and eight people on the ground [source: NTSB].

At times, the issue with weather lies in how pilots decide to handle it. Sylvia Wrigley, author of "Why Planes Crash," mentioned in a 2014 BBC News interview that she couldn't recall a crash where weather was the sole cause. "However, weather can create situations that increase the risk of something going wrong," she noted [source: BBC News].

One weather-related hazard is continuation bias — the tendency to stick to an original plan despite unfavorable conditions. This bias might prompt a pilot to push forward to the destination instead of diverting due to weather, sometimes leading to catastrophic outcomes [source: DeAngelis].

2: Intentional Crashes

Unfortunately, not all aviation disasters are accidental. Bennett estimated that around 10 percent of crashes result from sabotage [source: Bennett]. PlaneCrashInfo.com places the figure slightly lower, at 9 percent [source: PlaneCrashInfo.com].

Intentional crashes have frequently involved bombs placed on aircraft, such as the device in a suitcase that Libyan agents allegedly planted on Pan Am Flight 103, which exploded over Scotland in 1988, killing 270 people [source: FBI]. Other incidents include hijacked planes deliberately crashed, like those in the September 11, 2001 attacks on the World Trade Center and the Pentagon [source: National Security Archive].

Some airliners have been shot down, such as Malaysia Airlines Flight 17, which was struck by pro-Russian separatists in Ukraine in 2014 [source: CNN].

A rarer and more troubling scenario involves suicidal pilots intentionally crashing planes, taking the lives of passengers and crew. The Aviation Safety Network records 14 such cases since 1976 [source: ASN]. This includes the controversial 1990 EgyptAir crash near Massachusetts, which killed 217 people. The NTSB attributed the crash to "the relief first officer's flight control inputs" [source: NTSB], a conclusion disputed by Egyptian authorities [sources: NTSB, Walsh].

1: Other Human Mistakes

Approximately 10 percent of aviation accidents stem from errors made by individuals other than flight crews, such as air traffic controllers, maintenance engineers, and others, according to Bennett [source: Bennett]. PlaneCrashInfo.com attributes 10 percent of crashes to "other" factors, including mistakes by ground crew, improperly loaded cargo, runway obstructions, and random events like bird strikes [source: PlaneCrashInfo.com].

Errors in the control tower can have severe consequences. For instance, in 1991, a collision between a commuter plane and a jet airliner on the same runway resulted in 34 fatalities. The NTSB blamed local air traffic control management for failing to implement necessary safety measures and criticized the FAA for inadequate oversight [sources: NTSB, Malnic].

Fortunately, controller errors are rare. A 2013 FAA study revealed that U.S. air traffic controllers made 4,394 errors while managing 132 million flights in a year. Only 41 of these were classified as "high risk," with seven potentially leading to catastrophic accidents [source: Halsey].

Maintenance errors can also lead to catastrophic crashes. For example, the 1985 crash of Japan Airlines Flight 123, which claimed 520 lives, was traced back to a flawed repair done years earlier. This defect allowed fatigue cracks to develop, weakening the bulkhead and ultimately causing a devastating failure [source: FAA].

Discover more about aviation disasters in "Bracing for Impact: True Tales of Air Disasters and the People Who Survived Them" by Robin Suerig Holleran. Mytour selects related titles based on books we believe you'll enjoy. If you decide to purchase one, we may receive a share of the sale.