The upside is that the engines are up higher, making them less prone to ingest gravel.
The downside (for northern operations) is that they're perfectly positioned to ingest ice coming off the wings. I think there was at least one MD-80 crash caused by that.
Everything russian, from Antonov to the Bear bombers, are designed for rough strips. The classic russian design criteria are high-wings and oversized landing gear. The classic american design is tiny gear and low wings placing the engines within feet of the ground.
But the literal flip side to this is maneuverability. The russian approach (high wings sloped down) results in better turning and roll performance. If you look at american military planes, especially the cargo planes like the c5, they are generally look more russian with neutral or even negative dihedrals, high wings and high engines.
It does, if I remember correctly (I used to obsessively read about airliners but haven't in a while). Rear-mounted engines require specialized equipment to gain access, so you see them less on larger, newer aircraft. Same for the wings. Somebody correct me if I'm wrong.
Specialized equipment = Ladders. Having engines close to the ground means you can open doors and check things without climbing 10, 20, 30 feet into the air.
Short runways yes, but gravel kits were only offered on the 737-200 series with its low-bypass turbofans. The enlarged nacelles required to retrofit high-bypass turbofans to the already low 737 design ended that possibility.
The 717 is actually not an original Boeing or McDonnell Douglas design; it's a refinement of a very old DC-9 airframe from the 60s massively upgraded with modern avionics and modern systems. The DC-9s (and later, the MD-80/90s) were very well-engineered aircraft, and the fact that their core airframe designs are still in operation some five decades later is a testament to how sound Douglas' original engineering and design methodology was.
I'm not an airplane engineer, but I think a fair amount of it is technical debt, not the quality of the DC-9 design. For example, the 737 - a competing design that came out around the same time - is not only still being made, it's is getting prepped for another minor revision (the 737 Max), and the newest narrowbody airliner design in common worldwide usage (the A320 series) is going on 30 years old. The 717 was launched as the MD-95, a project at McDonnell Douglas to update the DC-9 series for the 90s, and Boeing (after merging with McDonnell Douglas) mostly just built out the already-sold MD order book and then shut the line down.
It would likely be very good for a manufacturer to make a new, clean-sheet design with updates like a carbon fiber fuselage, but the time needed to bring such a product to market would cause major problems for any company attempting such a project.
Several such craft exist at the bigger end of the regional jet market. There's the Sukhoi Superjet 100, for example: https://en.wikipedia.org/wiki/Sukhoi_Superjet_100 or the Embraer 190/195. These are both post-2000 airliners that have sold or been ordered in the hundreds (in the case of the Embraer E-jet family, total orders exceed a thousand), which carry around 100-110 passengers in 2+2 or 2+3 seating, and which are designed for much the same market niche.
The reason the 717 is popular is because the airframes are fully depreciated; the cost more to run than the newer jets, but are much cheaper to buy or lease. (Source: a guy I know who used to work in Finance for Allegiant, back before they began to diversity from MD-80 family planes.)
This is in addition to established offerings from Embraer and Bombardier (and some Airbus and Boeing at the very high end of the regional jet market with the A-318 and the smaller 737s). Each of these is more or less a clean-sheet design. The CSeries is already in flight testing.
Indeed, not mentioning it's the last version of the venerable DC-9 is a major omission. When I started flying from home for educational reasons in late high school in the late '70s Ozark Airlines was all DC-9s, and they sure seemed to be excellent.
You'd have to think though that a frame built long before CAD and long before you could stress test member components digitally would be much heavier for the same strength (or weaker for the same weight) than a modern airframe which could be min-maxed to high hell before a single sheet of aluminum was stamped.
The DC-3 was famously overbuilt because Douglas had no experience with large aircraft and played it safe. The result was the DC-3 was a very robust aircraft, and this contributed to its many decades of service (and still doing so today).
Not only would it need to contend with the massively successful Boeing 737 series and the Airbus A320 family but also the upcoming Bombardier CSeries which is an unusually efficient plane .
It was also built with the philosophy that it doesn't really matter what you build the aircraft from as long as the engine is big enough. Of course this hurt its fuel efficiency, but in some ways this was a good thing. The mission it was designed for (intercepting supersonic bombers) doesn't require the plane to loiter and the short range meant it would be difficult to defect with.
Absolutely no difference. Only a handful of near-modern planes (a-10) have any real armor protecting the plane itself. Pilots often sit in metal tubs, but the overall plane is unprotected from anything physical beyond bird strikes. Any protection is incidental to the structural requirements.
There might be something to say for a metal with a higher melting/yield temp that could survive longer in a fire but I don't think that enters into the design equation.
They would have built it from titanium but at titanium welding hadn't been figured out too well then. The Alfa sub hulls were done with plutonium rods if I remember right!
As I /really/ don't want to search those terms in order to confirm it... I'm just going to point out that it seems like meatysnapper is saying:
Alfa sub hulls were done (, welded using,) plutonium (welding) rods; according to their memory. Not, as another reply speculates, made out of plutonium rods (which sounds silly from all sorts of perspectives).
80ish % steel. The 25 did use some aluminum and titanium where needed. The good engineering was in determining where steel was good enough and where it wasn't.
Back when I flew regularly the MD-80 and derivatives where my favorite planes to fly because of 5 across rows with wider seats than the 6 abreast 737 which is like flying in a cattle car. My least favorite for long haul trips was the 777. Twelve hours where the seat armrest would go up only part way was too much. It made it very difficult to take advantage of adjacent vacant seats or just cuddle with my wife.
The seat armrest is a property of the seats (which are chosen by the airline) rather than a property of the aircraft, so you should blame your choice of airline rather than the perfectly fine 777. I often fly on Air France's 777s between Osaka and Paris and the armrests go up fully.
In terms of comfort my best flight in coach was on a Korean Airline A380: spacious and quiet; my worst on a JetStar A330 in cattle-like configuration. But I won't blame/praise Airbus: even though quietness is certainly a quality of the aircraft, the seat layout is absolutely a choice of the airline, so I now avoid JetStar like the plague.
Not to mention how amazingly QUIET they can be! In the front of the cabin the engines were a barely discernable whisper. Also, I was always intrigued at how far back the wings are mounted, probably due to the rear engines bringing the center of gravity further back.
Man, I HATE the MD-80 and the 717 and every other plane with body-mounted engines. There's always a beat frequency between the two engines and that's ok for the first couple hours but eventually it drives me crazy. Would be nice if they could somehow lock the engine speed perfectly.
Well, it's got plenty of company, including First World ... Ryanair, about which I've heard little good, except of course the price (no at fault accidents, but they're cutting it fine with fuel).
I'll let you know on Monday - I'm flying with them for the first time, BRS-DUB.
I live in Australia and people like to complain about the low-cost airlines there but, really, until you've travelled on Europe's low-cost carriers you haven't seen anything.
I clicked a bunch of links in the menu bar and they 404ed. My guess is this is a page in a semi-mockup state that isn't "really" live. The page is also in a weird mix of English and Russian, and thus it looks like this English site isn't really done.
I had to check this to see if it was true...and it is!? Why are they doing this? You can't even click on it to get taken to an email address or some other way to collect money from you.
"global demand has outstripped supply since Delta started assembling a large and growing fleet in 2012, taking advantage of favorable rental terms and a drop in jet-kerosene prices that makes older planes attractive.
“They’re kind of the market-maker,” said Robert Agnew, president and chief executive officer of aviation consultant Morten Beyer & Agnew Inc. “If Delta weren’t there, the airplane might be struggling.”"
That's the core of the story. It could have been some other model instead. It'd be interesting to know what the circumstances were behind Delta picking the 717.
It might have been a different model, but it is not obvious which one would it be
That one segment has some contenders: fokker 100, MD80 (big with AA), even older 737 models in that seat range
AA is in the process of retiring its MD-80s. Between their fleet of 737s, the A320-family craft they got in the US Airways merger, and the A319s and A321s they have on order, the Mad Dog's days are (thankfully) numbered.
"The only one that’s sitting idle and not earmarked for another carrier is a Turkmenistan Airlines plane in temporary storage" I don't get it. Why would you park an airplane idle?
Generally because aircraft are extremely expensive to operate and it makes no commercial sense to run them if none of the routes available to your airline can be operated at a profit during a particular time period.
(There is a charter and short term lease market, if someone else has a route they can run that aircraft on over that period, but it's probably not much of one for a 717 in Turkmenistan Airlines livery)
Aircraft also have periodic maintenance checks, some of which require the aircraft to be on the ground for an extended period of time. Same applies if the aircraft is having damage repaired. These may also show up as in temporary storage in Ascend's database (source: I used to sell it)
Because you don't have the money on hand to return it to flight (ie a part needs replacement). Or it is being held by some creditor and its storage should be called a seizure.
There are lots of very expensive parked planes. Ever watch the mythbusters? All the stunts they do with jet engines are with a group of parked 747s. The engines have to be runup every so often to maintain flight readiness.
It might make sense for a small airline to order a spare plane, just in case it's needed at some point. Especially if that plane model matches their flight profile really well, but also had a small production run so it would be difficult to lease a replacement. And if Boing really wants to get sales of the plane to make it look like a success, there might be a sweet price for that extra plane.
And since plane age is measured in takeoff/landing cycles, a plane that is sitting in storage isn't really aging.
Aeroplane age is generally measured in total hours flown.
Turbine engine life is measure in a combination of cycles and operating hours.
A piston engine aeroplane has nothing measured in takeoff/landing cycles, although it is good practice to record this information on the Maintenance Release.
There's no one measure for aircraft age. Flight hours, takeoff/landing cycles, and pressurization cycles are all measures that tell you different things.
The program I work on tracks flight hours, engine operating hours, and takeoffs/landings.
Many of us might remember the miraculous Aloha Airlines Flight 243, a 737 bought new by the airline in 1969, which in 1988 after 35,496 flight hours, but over 89,680 takeoff and landing cycles, lost 1/3 of its top fuselage and one flight attendant (it did a lot of short flights between the islands see https://en.wikipedia.org/wiki/Aloha_Airlines_Flight_243). Per the Conclusion of the Wikipedia article:
Under current FAA regulations for the Boeing 737 (line number 291 and prior) established in the 2010s, this airframe would have had to be permanently withdrawn from service after 34,000 flight cycles or 34,000 hours, whichever came first (for production number 292 and higher, it was increased to 75,000 flight cycles and 100,000 hours). The nearly 90,000 flight cycles exceeded the design limit of the 737-100/200 under either construction model.
Yes, this was the example in my mind, thank you for posting about it. Flight hours weren't informative enough in the case of this aircraft because it spent its time making short hops involving lots of pressurization cycles.
It's not strictly true that aircraft age is measured in takeoff and landing cycles and YoY depreciation is pretty huge for new aircraft even holding condition constant, but I'd agree that it might make commercial sense to keep a >10 year old 717 on standby. More likely to be short term fluctuations in demand or a short term airworthiness issue than any intent to have a "spare" aircraft though.
> ... and a drop in jet-kerosene prices that makes older planes attractive
Based on that one comment, said in passing, the cost of jet fuel has dropped enough that airlines now are looking for less-efficient designs.
That seems dangerous. Is airline fuel subsidized like automotive fuel is? At least, I doubt the airlines pay for the massive externality of climate change.
Fuel costs for an airline operating a regular schedule are much higher than their aircraft's capital cost, so changes to airlines' fleet plans induced by unexpected breaks in rising fuel price trends only really happen at the margin.
Where an airline chooses less-efficient designs it's usually because it's realising [partially] compensating efficiency savings by sharing pilots/engineers/equipment with similar aircraft it's already operating rather than simply because they cost less to buy.
Given the variety of specific notionally pro-environment levies on airlines and their passengers as well as on the fuel, figuring out how much per seat mile airlines actually pay is nearly as complex as guesstimating how much that aircraft's externality might be....
That's a good question. My understanding always has been that it is, especially in many indirect ways. For example, tax breaks and other government benefits for the oil and gas industry, as well as for the automotive industry. But I can't cite any off the top of my head.
One way it's indirectly subsidized, at extremely high cost, is the use of the U.S. military to protect industry assets, especially in the Mideast where we maintain a large, active military presence. As just part of the cost, the Iraq war cost the U.S. over $1 trillion. I very much doubt we would have been involved if there wasn't so much oil in and around Iraq. On the other hand, every import or export business relies on the peace, stability, and secure sea lanes provided by the U.S.'s foreign operations (military and diplomatic).
https://en.wikipedia.org/wiki/Gravelkit