Why Upgrade Aging Fleet?

Recently, i’ve been racking my brain as to why an airline would replace or why a start-up would by new (more fuel-efficient) aircraft, when they could buy older (less fuel-efficient) variants of the same aircraft for much less.

For example, say i’m starting a cargo airline. I’ve seen 747-200Fs available for $9m. Conversely, a new 747-8F would run me approximately $300m. I understand that the 747-8F would be more fuel efficient, by why would it ever make sense to pay 30X as much for the airplane itself? Atlas Air is a perfect example of this. They operate dozens of 747-200Fs. They recently placed an order for 12 747-800Fs. Why? Why wouldn’t they just buy more 747-200s? Sure, the airplanes look good to the trained eye, but how could it possibly be more profitable to them?

Also, how do airlines pay for their new aircraft? Do they finance it over 30 years or so?

Fuel is one component of the operating cost. Maintenance, labor and downtime are big factors too. If the old plane is broken, you don’t make any money, fail your customer and pay for your crew to stand around.

Airlines finance, lease and own their planes. I think Southwest owns (pays cash for) about half of their fleet and leases the other half.

Airline lease agreements are very complicated, they can do a leaseback with a bank, or a 12 year loan, or a tax back lease, manufacturer financing, etc…

The bottom line is that the airline is in the driver’s seat when it comes to loans. Nobody knows how to go bankrupt like an airline. They are the party who is taking the least risk of everyone involved.

The other party is making the assumption that at the end of the agreement, there will be a value associated with the airplane, and they can unload it to someone else (ATA is a great example) if the agreement terminates prematurely.

You may have heard that a properly maintained airplane can fly indefinitley. This is not really true of pressurized airplanes. There is a limited number of times a plane can be pressurized because pressurizing a plane is very similar to blowing up a balloon. The forces of expanding pressure exerted on the fuselage by repeated pressurization cycles eventually causes metal fatigue, and ultimately failure at some point. Sooner or later the plane’s gonna break for good!

Read about the Aloha Airlines Flight 243 incident

The age of the aircraft became a key issue (it was 19 years old at the time of the accident and had sustained a remarkable number of takeoff-landing cycles - 89,090, the second most cycles for a plane in the world at the time - well beyond the 75,000 trips it was designed to sustain).

A properly maintained aircraft CAN fly indefinitely.

The Aloha aircraft was only 19 years old - the accident was a result of what was at the time fairly new technology where the long term effects were not fully understood. Now, the effects are understood and aircraft are properly maintained and monitored to prevent those types of problems.

For example, many of Northwest’s DC-9’s are over 40 years old, over twice the age of the Aloha 737.

The primary reasons for fleet renewal are to reduce fuel cost, to reduce maintenance expense, to get a refreshed onboard product at the same time, and to access new and different types of markets (for example the 787 can fly further than any aircraft its size currently available and for a lower Cost per seat mile, the regional jet revolutionized the range of markets that could be accessed by regional aircraft from a hub).

But the Northwest DC-9s can easily have experienced less than one quarter the cycles of the Aloha 737!

Even if the DC-9s flew every day of their lives and experienced one takeoff and landing cycle per day, that’s still only 14,600 cycles. Compare that to the 89,090 cycles the Aloha 737 had experienced. :open_mouth:

A typical NW DC9 does 5 or 6 cycles a day. Remember that they only fly stages under 1500 miles in length (and mostly under 1000 miles).

Just so we’re on the same page, a cycle is one takeoff and landing.

Five legs a day seems excessive to me, but even if correct they don’t do it every single day of their lives. I’d be interested to hear what the cycle count is for representative example of the DC-9 fleet.

Five legs doesn’t sound excessive. That would only be 2.5 roundtrips a day. My guess is 6 to 7 cycles (i.e. 3 to 3.5 roundtrips a day).

My guess is that they do 6 or 7 cycles on weekdays and 4 or 5 on weekends. Taking into account maintenance requirements, I would say each DC-9 flies only 45 to 50 weeks a year, depending on whether the heavy maintenance is due.

Google is your friend. Your data may be found here:
airliners.net/aviation-forum … in/1200000
flightglobal.com/pdfarchive/ … 02869.html

Well Y’all suckered me in…

My buddy who flies 319/320’s for North West averages 6 legs a day (just during his 8 hours). He usually start’s in Vegas and goes back-and-forth to Cali a couple times then heads to the east coast, and sometimes back. I’m sure the AC is then turned and flies another bunch of legs under a different crew for 8 hours… and then again for 8 hours… etc.

Granted 40 year old Dogs may be limited to a certain number of cycles per day etc.

Also the Aloha spent it’s relatively short life flying a gazillion short hops around the islands and was probably constantly either expanding or contracting the entire time it’s engines were running.

Thanks for the updates guys. I hadn’t realized anyone was still flying that many legs per day in anything other than turbo-props. But, stands to reason they’d be maximizing the number of legs per day on the entire fleet.

But, given the strict noise regs at every airport I’m familiar with, is anyone actually still flying 24/7 domestically?

Yes. I’m going on the assumption you mean aircraft are landing and taking off at all times of the day.

FedEx, UPS, and other cargo carriers quite often land during the middle of the night. Southwest has flights landing as late as 01:00 and other major airlines have flights that arrive between midnight and 06:00.

While many airports do have stupid restrictions on operating at night, I would say most of the airline served airports have 24 hour operations. All of the major hubs are.

Most passenger flights do arrive between 07:00 and 22:00 just because people don’t want to arrive at their destinations in the wee hours of the morning.

My friend actually bids exclusively for “night owl” flights because he prefers the weather and low traffic and rants on and on about his final east-bound leg of the day up in the jetstream where the sun rises abnormally fast in the windscreen. 8)

Let’s hope!

Consider Southwest’s aircraft. They are 737s, of course, but some are still over 20 years old. I estimate that Southwest has just over 7 cycles a day per aircraft based on the average of 647 miles per trip (from the latest Southwest financial press release). I estimated 647 miles to be about 1.75 hours and, with a daily utilization of 13 hours per day, this comes out to just over 7 cycles day.

After doing that computation, I did some research on the the web. Here’s what Wikipedia says:

As of September 2008, Southwest has an average fleet age of 13.5 years, and fly an average of about 7 flights per day. The average aircraft trip length is 633 miles (1,019 km) with an average duration of one hour and 48 minutes. This means the daily utilization of each plane is, on average, 12 hours and 36 minutes.

Southwest’s fact sheet (the Wikipedia article referenced the fact sheet) states states

The Company’s fleet has an average age of approximately 10 years.

The average aircraft trip length is 635 miles with an average duration of one hour and 55 minutes.

Southwest aircraft fly an average of 6.2 flights per day, or almost 12 hours and 9 minutes per day.

Yep, that’s probably true, but when you’ve got a 90 year old plane that has used 3 different avionics packages, went through 7 different engine overhauls, has none of the original aluminum skin left and had the interior done 17 times, you have to look at your spreadsheets, and look at all the money you spent, and see if it was worth it or if you should’ve sold it while you could and got something new.

Sounds like most DHC-2’s- all you need is the data plate. They send divers in Alaska to recover the bodies AND the Data plates when they go down in the water

You say that as if that’s a regular occurrence… :open_mouth:

It has happens more times then I wish i knew about.

If the following is not true: Properly maintained jet aircraft can fly forever - then how is the U.S. Air Force able to keep B-52s, built in 1955, in operational service until 2040?