Airlines have been increasingly outsourcing repair and upkeep work to other countries, but experts and consumer groups disagree about its impact on safety.
The cause of the fatal plane crash in South Korea last month is still to be determined, but it thrust into the spotlight a subject little understood by the general public: how airplanes are maintained.
Jeju Air, the airline that operated the flight in which 179 people died, said that checks before the flight had raised no concerns and that the jet, a Boeing 737-800 that was about 15 years old, had no history of accidents.
While there is no evidence that poor upkeep played a role in the crash, experts say that the plane’s repair history, which includes work performed by maintenance firms in other countries, will be an important part of the crash investigation, as is typically the case.
Here’s what you should know about how airplanes are maintained.
The Basics
Airline executives, pilots, mechanics, regulators and others play vital, and overlapping, roles in taking care of commercial jets.
At the front line is a practice that will be familiar to many travelers even if they don’t know what it is called: line maintenance, which involves regular inspections and repairs between flights. Before a jet takes off, pilots perform visual and other inspections for damage or other problems. Airline mechanics also conduct periodic checks. Often, a mechanic can troubleshoot a problem quickly, fixing it or safely patching it up until the issue can be addressed later. Serious problems can result in a long delay or cancellation.
In addition, every part of a plane, down to the nuts and bolts, is subjected to routine inspections, repair or replacement. Those checks are typically scheduled based on how many hours the plane has been used, the number of flights, time or some combination of those 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.