The cause of last month’s deadly plane crash in South Korea has yet to be determined, but it brought to light an issue little understood by the general public: how planes are maintained.
Jeju Air, the airline that operated the flight that killed 179 people, said pre-flight checks had raised no concerns and that the jet, a Boeing 737-800 that was about 15 years old, had no history accidents.
While there is no evidence that poor maintenance played a role in the crash, experts say the plane’s repair history, which includes work performed by maintenance companies in other countries, will be an important part of the crash investigation, as it usually is.
Here’s what you need to know about how to maintain airplanes.
The Basics
Airline executives, pilots, engineers, regulators and others play vital and overlapping roles in the care of commercial jets.
At the forefront is a practice that will be familiar to many travelers even if they don’t know what it’s called: line maintenance, which includes regular inspections and repairs between flights. Before a jet takes off, pilots perform visual and other inspections for damage or other problems. Airline engineers also perform periodic checks. Often, an engineer can quickly resolve a problem, fix it, or safely repair it until the problem can be addressed later. Serious problems may result in long delay or cancellation.
In addition, every part of an airplane, down to the nuts and bolts, undergoes routine inspections, repair or replacement. These checks are usually scheduled based on how many hours the airplane has been in use, the number of flights, the time, or some combination of these factors. These inspections are overseen by aviation authorities around the world, with many following the lead of regulators at the Federal Aviation Administration or its European Union counterpart.
When it comes to more intensive maintenance that can take a plane out of service for days or weeks, the world’s largest airlines do much of that work themselves. Some, including Lufthansa and Delta Air Lines, even sell these services to others. However, every airline outsources at least some work to companies that make parts and planes, such as Boeing and Airbus, or to third parties. Small carriers, especially, depend on the practice.
“If you look at the long tail of aircraft operators, the majority are very small, so it never made sense for them to invest the capital,” said Jonathan Berger, founding partner of Alton Aviation, a consulting firm. “Outsourcing has been going on since the beginning of time.”
The rise of outsourcing
Although it has always played a role in aviation, outsourcing has accelerated in recent decades. In the United States, the share of outsourced airline maintenance costs more than doubled from 1990 to 2011, rising from about 20 percent to more than 44 percent, according to a 2012 Congressional Research Service report. airlines typically do not disclose such costs, and few outside the industry track or estimate them.
Around the world, airlines still perform almost all of their own line maintenance. But they often send more comprehensive work to companies that specialize in aircraft maintenance, repair and overhaul. This work is usually divided into three categories, covering the airframe—or the body, wings, and tail of an airplane—the engine, and various other components.
Labor accounts for most of the cost of maintaining the airframe, so airlines in wealthier countries often send that labor to countries where wages are lower. Some US airlines send planes to El Salvador, for example, and Western European carriers send them to Eastern Europe.
With engines, materials are more than the cost of repairs, so outsourcing to lower income countries doesn’t save airlines that much. However, much of this work is also outsourced, often to engine manufacturers, because repairing these large machines is expensive and complicated, according to Mr. Berger. Most jet engines for large commercial airplanes are manufactured by several American and European companies.
The global network of maintenance providers is a growing market valued at over $100 billion. Proponents say it allows airlines, particularly budget carriers, to plan costs and focus on what they do best: planning, selling and operating flights efficiently. Airlines also benefit because they can call on specialists who may focus on certain types of maintenance or aircraft.
Is outsourcing safe?
Many aviation industry experts say outsourcing is safe and necessary, and note that the FAA still oversees the maintenance of American planes wherever it occurs. However, some consumer groups and labor unions representing American engineers have raised concerns about it.
“There is a quality issue and for the industry to deny it is just false,” said William J. McGee, who has spent decades advocating for passengers before lawmakers and regulators and is a senior fellow at the American Economic Liberties Project, a progressive group. .
In the 2000s and early 2010s, the Transportation Department’s inspector general looked at FAA oversight of foreign and domestic repair stations and found it nonexistent. Airline engineers reported finding obvious faults in planes being returned from foreign repair shops. And their unions, including the International Brotherhood of Teamsters and the Transport Workers Union, have raised concerns that workers abroad are not held to the same strict standards as those in the United States.
The FAA recently addressed some of these concerns. This month, a new agency rule will begin requiring foreign repair sites to drug and alcohol test employees who perform certain safety-sensitive maintenance, affecting as many as 977 locations in 65 countries.
“This rule will ensure that these workers are held to the same high level of safety standards regardless of where they are physically located,” Mike Whitaker, the FAA’s outgoing administrator, said in a statement last month.
Outsourcing advocates say oversight by airlines and the FAA today is tight, noting that despite some shocking accidents and incidents, flying commercial airplanes is far safer than other common modes of travel, such as cars, buses or trains .
Maintenance needs are increasing
Despite a significant slowdown early in the pandemic, air travel has rebounded much faster than the industry expected. Airlines are now willing to expand and upgrade their fleets.
However, Boeing and Airbus, the two major jet manufacturers, have struggled to create planes. Boeing has had to slow production in recent years, first after two fatal crashes in 2018 and 2019 of its most popular plane, the 737 Max. Last year, it was forced to do so again after a panel blew up a Max jet in flight, and in the fall it largely halted Max production during a seven-week strike.
Airlines have also had to take Airbus planes out of service to carry out surprise checks on Pratt & Whitney engines after the engine maker discovered a quality defect. Airbus and Boeing have also faced pandemic-era problems, including shortages of parts and skilled workers.
The slow delivery of new planes has forced airlines to use older planes for longer, which is safe but often requires more maintenance. Newer engines, which are packed with new technology that makes them more efficient, also require more repairs and maintenance than expected.
But the number of people pursuing careers in aircraft maintenance has lagged behind demand.
“Not only are airlines hiring, general aviation is hiring, corporate aviation is hiring,” said Chuck Horning, professor of aircraft maintenance at Embry-Riddle Aeronautical University, referring to planes used by many businesses to transport people and goods. . “And then you have industries that didn’t even exist when I graduated in 1986, like the space industry and unmanned aerial systems.”
