What determines an airplane’s lifespan?

very interisting article.although why would a newly built airplane after only flight tests would be scrapped,is a waste of time money labour and why not put the airplane on display in a museum for others to enjoy?

I have to agree with Carmine, great article, but what a tremendous waste of time, efford and money. And forget about a museum, they could have put that baby right in my back yard.

i am glad to know that you care about safety,and what the genaral public thinks.it may be very difficult and expensive to determine an air plane's flight worthiness,but sometimes we have to think outside the box.i am not sure how pressurization work in an air plane,or the process that has to be use.perharp the design and complexity of its mechanical and the sensitivity of the wireing make it difficult to perform other less expensive test.maybe the airplane companies need to consider designing their planes differently.

More info on the ultrasonic phased-array technique for NDE can be found at http://www.bercli.net/documentation/phased_array.htm (updated link).

With newer materials like carbon fiber and other composites, why can not aircraft manufacturers make use of them instead of the perennial aluminum that is less durable? Then they should also design the aircraft that sections can easily be replaced thus extending their flying lives longer. When I see aircraft bone yards split familiar aircrafts in only a few minutes for recycling a part of me is also dies with the plane especially if they have made historical flights in the past.

Boeings new airplane the 787 which has not flown yet is made with composite materials and may not suffer from the fatigue problems todays aircraft have.

Boeings new airplane the 787 which has not flown yet is made with composite materials and may not suffer from the fatigue problems todays aircraft have.

How frequent do the airliner conduct an inspection to an airplane? Do they conduct it on daily,weekly,monthly or distance of flight basis?

I found this article very interesting. This to me brings up another question. Why is it some airplanes last longer than others? Like, has anyone figured out why the DC3s can still fly while planes far younger are long gone?

I agree. A very interesting article. Could anyone tell me how to get into aircraft recycling career?. As a Senior Project Manager with Aviation in my heart I would love to be managing projects to preserve aircraft.

Re. Louis, for one thing, DC-3s weren't pressurized airplanes, nor were B-17s or piston fighters. B-29s were pressurized but in a year or two's service I imagine they didn't go through nearly as many pressurization cycles as a jetliner. In regards to fatigue cracks, it is interesting that the first DeHavilland Comet jetliners had rectangular windows - the window corners were the perfect place for cracks to propogate from, which caused the infamous catastrophic failures in early Comets. Metals and their properties is a fascinating subject.

The answer to the question “why do some planes stay aloft longer than others?” is an easy one. Money money money! Is it worth it to keep em’ flying? Look at the balance sheet. Airlines and museums work on the same principle; they do what they can with the money they have. Of course, the military is a little different….

At first one would think with today's technologies, different materials could be used to increase the length of time planes remain in service. But after reading clay's comments, he hit the nail on the head, it's all about money... -Stephen Personal Injury Lawyer NJ

How do airlines determine if metal fatigue has developed in their passenger-liners? Bob Eastin, an FAA specialist on aircraft fatigue, says, "[Airlines] are really relying on the manufacturer's maintenance programs. I think that it is great that they do rely on manufacturers. Why not? Mikhail at fat loss 4 idiots guide.

Yeah, the limiting TECHNICAL factor may be metal stress and fatigue, but the possible FINANCIAL limits are endless: engine fuel consumption vs upgrades vs scrappage, the structure of the original purchase [actual ownership vs lease], who owned the airframe and for how long, which airline had it last and for what purpose, etc. ad nauseum. Most of the aircraft now in long-term storage in the desert will never fly again, though most of them are or could be made to be airworthy - just not economically. These airplanes are technically not "worn out", but no one wants to spend the money to keep them flying commercially, because there are more economical alternatives. AA just announced a major conversion to 737-800s to replace a bunch of their MD-80s, not because the latter are so near to their technical demise, but because they use more fuel and are starting to become a maintenance nightmare. Same reasons you trade a used car for a new one....only in this case the used one never goes back on the road because no one wants it.

I have to agree with some of the other postings here. With today's technology and materials, one would think planes should last longer. If the lifespan of a plane can't be lengthen, there won't be enough museums around to showcase all the scrapped planes. Scott Philadelphia Wedding Photographer

In response to Louis Steiner's question about why DC-3's are still flying while many younger aircraft are not, I recall a conversion between the co-pilot of a DC-3 that a group of us was going to fly in and one of the passengers. He asked: "Is it safe to fly on an airplane this old?" to which the co-pilot responded:"How do think it GOT TO BE THIS OLD?!!" Probably the main reason that the DC-3 is still in the air is because the aircraft is so underpowered that the airframe doesn't get a stressed as aircraft with more power. (I wonder if anyone ever though about replacing the Pratt & Whitney R-1830's with R-2800's during the war.) Also, the DC-3 is built like a tank with rivets to match. Flush-riveted, the DC-3 could probably fly 30 knots faster.

The DC3 is not underpowered. Like all designs it was built to fly at the speeds it works at. It can fly on 1 engine. I flew in a Super DC 3. It was a C 56(?)(Navy R-6D or some number). It was a Navy version and took me from Okinawa to Kyushu in 1953. It was a DC 3 with different wings and empennage, powered by R-2800s. Those engines drank gasoline and the airplane was more expensive to operate, but it flew faster. No commercial versions were sold that I know of. Ask Douglas about their swept wing Super DC-3.

During mountain travels in a motorhome, the stored water bottles fatigue from constant exposure to various altitudes and temperatures. They all eventually leak from the constant flexing. Same effect but more drastic for aircraft components. DaFlikkers

My brother is an aircraft mechanic who repairs smaller jets that fly domestic routes from Newark Liberty Airport. Due to the metal fatigue and the pressurization that the aircraft is put under, he tells me he is constantly changing fasteners and rivets on these aircraft. There is even a special technique to fasten the fasteners.

Can old airplanes be recycled into new ones? Why beverage cans or skateboards?

I understand why pressurization stresses the fuselage, but why does it stress the wings? The wings aren't pressurized, are they? EDITORS' REPLY: In a joint email we received from Deborah Hopkins of Lawrence Berkeley National Laboratory and Guillaume Neau of Bercli, LLC: "Although the wing isn't pressurized, pressurization of the fuselage might affect the stress state across the area where the fuselage and wing are joined."

Aircraft maintenance has a lot to do with life span too. For example the Joint STARS aircraft currently used as an intelligence gathering platform is based on old Boeing 707s, that have gone through a refurbishment to zero time them.

Fatigue strength is linear on semi-log paper, but must consider initial crack sizes (machine tool marks) crack growth rates. Composites don't weaken by fatigue, but in compression, the stiffest part (the fibers) are pre-buckled, and so don't contribute, making them less efficient. In tension because of the complexity in putting them together and getting them to cure, the theoretical strength is significantly reduced. Then, the bearing strength of plastic composites is reduced again, so riveted or bolted composite structures take a double hit. Some of the reason why an aircraft may be scrapped is economic: Their market niche has gone away. The BA-142 is an example of that.

You must also consider that the DC-3 remined in use because of operations cost, and the ability to perform duties that most airplanes cannot. The DC-3 even today is still a cheap medium size airplane to operate compared to a turboproped powered aircraft of similiar size like a king air for instance. In remote places like the bush of Alaska, or the Australian Outback the 3 can get into and out of rugged dirt strips carrying oversized cargo and it is big enough to be used as an air ambulance or a transport. In fact the army up in to the mid 70s used the DC-3 for a variety of purposes Such as transporting troops,hauling cargo, gunships, and as staff transports they were known as C-47s

Can anyone tell me how to get into aircraft recycling career?

In response to an earlier comment; the Super DC-3 was used by several smaller airlines. Capital Airlines was one of those. They sent three older DC-3's to Douglas who added a six foot section aft of the cockpit, installed the bigger engines and nacelles, modified the wings and vertical stabilizer and added steps to the cabin door to expedite passenger entry and exit to reduce loading and ground time. The conversion made a degree of sense on Capital's many stop flights, like The Tobacco Road routes from DC to Memphis with eleven stops, but was not a commercial success in competition with the Martin 202/404 and Convair's of the day.