Just like laptops, printers or mobile phones, commercial aircraft eventually need to be replaced. Around 700 planes are retired every year. With aircraft, the stakes are much higher than they are with smartphones. A broken phone is a cause for annoyance and inconvenience. A broken or outdated airplane? That’s a much bigger deal. Aircraft are entrusted with the precious cargo of hundreds of lives. Their safety and reliability need to be beyond question.
Fortunately, the life span and regular maintenance/upgrades of commercial aircraft are strictly regulated. On average, they get replaced every 22.8 years, according to Statistica. But there are many factors to consider around their retirement, not to mention what happens to them after they’re put out to pasture. In the past 10 years, aircraft were replaced more frequently than they had to be because fuel prices went up, so aircraft were replaced with more fuel-efficient models.
There are other factors, too. Consider most aircraft cost between $60 and $115 million to replace. While safety must be the primary concern, that’s enough money that aircraft owners would want to make sure that they’re replacing a jet no sooner than is necessary.
When Do You Retire a Plane?
There are many reasons to decommission planes. One example is when a new, more cost-efficient model comes out, as mentioned above. Some planes, like the 747-400s at British Airways, were retired earlier than expected because they had too many premium seats to be profitable. Newer and very capable aircraft such as Singapore Airlines A380s were likewise sent to the scrapyard when perfectly functional: increased operating (fuel) costs meant they were unprofitable and no airlines wanted to acquire them.
Besides factors like fuel prices and seat types, the main consideration is safety. On average, a plane can fly for 30 years before it needs to be retired. Usually, a plane’s life span isn’t measured in years but rather in pressurization cycles. Every time a plane takes flight, it is pressurized, which puts stress on the fuselage and the wings. This is called metal fatigue. Short-haul planes, which undergo multiple takeoffs and landings each day, will have a shorter life span than long-haul flights.
A plane that undergoes too many pressurization cycles without being replaced has the potential to suffer damage to the metal. If you bend a paperclip over and over again until it snaps, you’ll understand the dangers of metal fatigue. When you put pressure on the same parts of the metal shell of the plane over and over again, this can cause pieces of the plane to break off mid-flight.
One of the most famous and tragic occurrences of this happened in 1988, when Aloha Airlines Flight 243 suffered explosive decompression due to too many pressurization cycles. This particular aircraft had over 90,000 flight cycles — well over double the safety limit. The plane experienced widespread metal fatigue cracks, causing a portion of the roof to come completely off the aircraft. There was one fatality and passengers were injured.
How Can You Tell How “Old” a Plane Is?
The Aloha Airlines flight had one positive outcome: it completely revamped aviation safety policies and procedures. You can read about some of the changes in the report the National Transportation Safety Board released after the incident. But one of the biggest causes of the failure was a failure to assess or maintain the plane.
Today, we have comprehensive safety measures in place to make sure that sort of incident can’t happen again. Safety-critical guidelines like DO 178C helped put more benchmarks into place. Ways to evaluate planes without taking them apart have become more accessible. Today, ultrasonic phased-array testing is a common non-destructive evaluation method which looks for imperfections by analyzing the echoes from ultrasonic waves to find cracks or welds. It’s kind of like giving a plane an ultrasound — you scan the outside to see what’s inside.
Although it is possible to maintain a plane beyond its pressurization limit, as the plane gets older, it becomes less cost-effective to maintain an old plane, and more cost-effective to simply buy a new one.
What Happens To Retired Planes?
Retired planes are headed to one of two places: another buyer or the scrapyard. If the plane is still safe to fly, or if a buyer is more willing to pay for maintaining an old plane than buying a new plane, a plane might be resold to another fleet. It’s worth noting that different countries have different plane safety requirements. What’s no longer thought of as safe in one country might still be considered safe in another.
When there are no buyers for old planes, they are typically sent to scrapyards where they’re disassembled for parts. This is an important consideration when deciding when to retire a plane. Besides safety or economic factors like fuel efficiency or seat type, it’s important to retire the plane early enough to be able to reuse certain parts, which can help recoup much of the cost.
IATA reports that when a plane is decommissioned at the right time, 90 percent of the parts can be reused or recycled. And there’s a huge market for those spare parts. GM Insights reported that the aircraft recycling market size was over $4 billion in 2020.
However, the secondhand plane-part market changes quite quickly, so many airplane owners will send their retired planes to plane graveyards to be kept until the owner judges the time is right to harvest and resell the part. These graveyards are typically in dry, spacious areas like Arizona and southern California.
Even with the most conscientious maintenance, most airplanes will eventually need to be retired. All in all, most experts say the average lifespan of a plane is about 22.8 years. As with any average, your mileage may vary.
There are many factors to consider when deciding how long to keep a plane flying: its age, pressurization cycles and flight hours. Another factor is whether there are more cost-efficient models to replace the plane with. And when planes do retire, it’s worth looking at the secondhand parts market to see how much you can recoup the cost of getting a replacement plane.
Vance Hilderman is an aviation expert, author and CEO of AFuzion.
