• DC-9, MD-80, B717: What’s the difference?

    by  • July 9, 2012 • Manufacturers • 21 Comments

    To the untrained eye, the three aircraft pictured below might look like they are the exact same type. Unless you are a serious aviation enthusiast, you probably can’t tell the difference between them at first glance. If you have ever wondered what the differences are between the Douglas DC-9, McDonnell Douglas MD-80, and the Boeing 717, then keep reading. But first, see if you can guess which aircraft is which.

    If you guessed the top was a DC-9, the middle a B717, and the bottom an MD-80, you were right. The truth is that all these aircraft were based off the Douglas DC-9, and together are considered the “DC-9 Family.”

    A brief history…

    The first of the type, the Douglas DC-9, was first introduced into service with Delta Airlines in 1965. It was developed by the Douglas Aircraft Company for airlines to use on short but frequent routes. Its main feature was its ability to utilize short runways, which allowed for the introduction of jet service to smaller airports that previously only saw propeller driven aircraft. Over 900 of the type were produced with the last delivery in 1982. Today, the main operators of the aircraft are Delta Airlines and USA Jet. They are slowly being phased out of fleets and will probably be nonexistent within the next couple of years.

    A Delta Airlines Douglas DC-9-50 climbing off of Runway 26L at Atlanta. (Photo by Kyle Dunst)

    The next generation of the aircraft was originally supposed to be designated the DC-9-80 “Super 80.” However, after Douglas merged with McDonnell Aircraft, its name was changed to the McDonnell-Douglas MD-80. The MD-80, and the later MD-90 variation, were much larger than the DC-9 they were based off of. The first of the type entered service with Swissair and Austrian Airlines in 1980. About 1,000 aircraft were produced in total, making it the most popular aircraft of the DC-9 Family. The largest operators of the type are American Airlines and Delta Airlines with about 200 and 100 aircraft respectively.

    A Delta MD-88 Lining up for departure on Runway 18C at Charlotte (Photo by Kyle Dunst)

    The most recent of the DC-9 Family is the Boeing 717. 156 of the type were produced in total, making it the least popular of the series. The last 2 of the type were delivered in 2006 to Air Tran and Midwest Airlines, marking the end of one of the most historic and popular aircraft series the world has ever seen. Just like the MD-80, the 717′s name came from a company merger. This time, the McDonnell-Douglas aircraft corporation was absorbed by Boeing Commercial Airplanes in 1997. The main improvement of the 717 over previous types is the state of the art, modern flight deck. It features 6 interchangeable LCD Displays and advanced computers. The largest operator of the type by far is AirTran. As the airline is absorbed into Southwest Airlines, the 717s will be transferred to Delta. This means that starting next year, Delta will operate all 3 types of the DC-9 Family.

    Air Tran Orlando Magic NBA Team 717-200 Logo Jet seen at Atlanta (Photo by Kyle Dunst)

    How to tell the difference…

    So now that you know how each variation of the DC-9 Family came to exist, you probably want to know how you can actually tell the 3 apart. Each variant has a few unique characteristics, both inside and out.

    The DC-9 has much smaller engines than the other two. It also features a pointier tail cone.  On the other hand, the 717 has large, bulky, powerful engines with a more rounded tail cone. The MD-88 combines the characteristics of the DC-9 and B717, which makes sense as it served as a transition between the two.

    The tail of a DC-9. Note the pointy tail cone and small, thin engines. (Photo by Kyle Dunst)

    Note the large, bulky engines and round tail cone on this AirTran Boeing 717. (Photo by Kyle Dunst)

    The MD-88 has the tail cone of a 717, but smaller engines similar to that of a DC-9 (Photo by Kyle Dunst)

    The best way to distinguish an MD-80 from the other 2, is that it is much longer with much wider wings. DC-9′s and 717′s are about 124 feet long, depending on the specific variant, with a wingspan of 93 feet. The MD-88 is an impressive 148 feet long with a 108 foot wingspan.

    For people with a decent amount of knowledge about commercial aviation, the easiest way to tell the difference is by what airline is operating it. For example, American Airlines only operates the MD-80 and AirTran now only operates the Boeing 717. As you become more involved in the aircraft spotting hobby, you quickly learn which airlines operate which types of aircraft. Delta, on the other hand, will soon operate the DC-9, MD-80, and 717. (So much for that method…)

    From the inside you can sometimes tell the difference by the seating layout. Delta’s MD-80′s have 3 seats on the left side of the aisle and 2 on the right, while its DC-9′s are the other way around. The 717′s cockpit is very unique and recognizable as compared to the other two.

    The cockpit of a classic DC-9 (Photo from pbase.com)

    A Modern Boeing 717 Cockpit (photo from hitechautomotive.blogspot.com)

    Next time you find yourself at an airport, try to see if you can figure out which is which.

    About

    21 Responses to DC-9, MD-80, B717: What’s the difference?

    1. richard holland
      July 10, 2012 at 2:52 pm

      Love those DC9′s Loud, smoky, lots of noise. The way planes should be. Tree huggers need not apply.

    2. AviationMan8
      July 10, 2012 at 3:34 pm

      Nice article. The MD-80 and MD-90 series aircraft were longer than the DC9, thus needing an additional door on the left side and rear of the fuselage. When the B717 was introduced, the fuselage length was reduced which eliminated the need for this door. You can tell the MD-80s from the MD-90s by the engine; MD-80s have a low bypass turbofan and the MD-90s have a higher bypass turbofan (larger engine inlet). The early DC-9s probably had turbojet engines which were smoky and noisey. You had to plug your ears for a DC-9, but not for the MD-90.

    3. John Billings
      July 10, 2012 at 7:24 pm

      I fell in love with the DC-9 IN THE FIRST FEW HOURS OF TRAINING (BACK THEN IT WAS MOSTLY DONE IN THE AIRLANE) AND STAYED WITH IT FOR 14 YEARS, STILL WOULD LIKE IT IF THEY WOULD LET ME…

    4. July 10, 2012 at 8:19 pm

      DC-9′s were equipped with various versions of the PW low-bypass turbofans (JT-8D), never turbojets. MD-80 variants were equipped with later higher by-pass versions of the JT-8D.

    5. Tom Inglima
      July 10, 2012 at 11:02 pm

      American Airlines first operated the MD-80 series airplanes in 1984. Not sure but I think the first ones were leased from MD. It was to be an interim airplane. Eventually American became the biggest MD-80 operator in the world with close to 400 of them, mostly MD-82′s and some MD-83′s.

      The airplane has always been an interim airplane until the next best thing came along. Even now with B-737-800′s fast replacing the MD-80′s there is still more 80′s that 737′s (that may have finally changed, if it hasn’t then it probably will soon. It will be interesting to see when the 80 finally goes away from American, of course with the airline in Chapter 11, it is hard to predict what is going to happen.

      Delta seems to be hanging on to them and is supposed to be looking for more MD-90′s,

      My son is an A&P mechanic who worked on B-727′s for much of his life and some DC-9/MD-80′s. Like most mechanics I know they do not really like Douglas airplanes, but pilots I know that Fly the 80′s love them.

      • thirtythousand
        July 10, 2012 at 11:07 pm

        Yeah, I can see Delta buying American’s MD-80′s during the bankruptcy process and/or merger with US Airways.

        • Deneal Schilmeister
          July 15, 2012 at 6:26 pm

          its already been announced that DAL is acquiring all the AirTran MD-90s from SWA.

          • Lj
            July 21, 2012 at 9:46 pm

            actually it has been announced that Delta will be acquiring 88 Boeing 717s from Southwest once SWA retrofits them for Delta.

    6. Ralph Boyes
      July 10, 2012 at 11:57 pm

      How did everyone miss one thing diferent on the DC-9′s and later varients? The early 9′s until the DC9-50′s did not have chines on each sides of the forward fusilage. These were to provide forward stability and any dent or damage was a no go item. Note that when the 717 went back to the shorter body the chines have disappeared.
      The tale cones are of course give aways, but true airplane geeks should know about the chines. As an airplane geek, I am shocked.

    7. Pingback: Midwest aitrlines | Tresencuerados

    8. Chez Funk
      July 13, 2012 at 7:04 pm

      Hey! Is that an 8-track player on the glareshield of the -9? Just kidding. That dashing board actually looks friendlier to me.

    9. Gary Moll
      July 13, 2012 at 10:55 pm

      And don’t forget, the DC-9-10 and -30 had a single exit door over the wing.

    10. Thomas Hess
      July 14, 2012 at 7:13 am

      If you want the nuts and bolts differences between ALL of the DC-9/MD-80/B-717 models, go here… Unless you’re a mechanic or engineer, there will likely be more information here than you realized was possible!

      http://www.airlinercafe.com/page.php?id=396

    11. Bill Tanksley
      July 14, 2012 at 9:40 am

      Some additional tidbits: the DC -9-30 had 2 over wing exits (-31 & -32). The MD-88 was originally a MD-82, but got the early glass cockpit added, this becoming the MD-88. And I believe the original type certificates are all shown as DC-9-80 or something to that effect.

    12. bob
      July 14, 2012 at 2:07 pm

      MD90′s not a bad machine. unfortunately, its 10k heavier than an 88, with the same wing. altitude is a problem. but hey, we got a powered elevator, carbon brakes and BAM’s! ( big a– motors)

    13. Arnie
      July 14, 2012 at 3:46 pm

      the best part of an older model 9 is the engine startup whine especially sitting aft of the wing.

    14. John Howard
      July 16, 2012 at 12:56 pm

      The DC9-10 had no slats, and very different landing charateristics than the other 9′s.

      The Dash 30 had chined tires, and the dash 40 and dash 50 had the nosewheel trucks to keep trash and water directed away from the engines.

    15. George
      July 19, 2012 at 9:39 am

      I flew in a brand new TWA 717 from Lambert Field in St. Louis. The cockpit was very advanced for the time. I think the pilots were still reading the manuals. It was a quiet and pleasant flight.

    16. Kenan Hays
      July 20, 2012 at 4:48 pm

      I began flying DC-9s in the late 1960′s; those of Continental, Texas International, and
      Delta. I like the 5 across (2 and 3) seating, even with the slightly smaller cross-section, since I was sometimes with one or two other people. As more and more of the DC-9s and MD-8Os are retired and replaced with 6 across seating in Boeing 737′s and Airbus 320 family, I will miss the availability of a choice.

    17. Tony Griffin
      March 18, 2013 at 12:53 am

      Also the vertical stabilizer on the 717 & MD-90 is different from the DC-9 & MD-80

    18. April 15, 2013 at 7:17 pm

      The best way to distinguish an MD-80 from the other 2, is that it is much longer with much wider wings. DC-9′s and 717′s are about 124 feet long, depending on the specific variant, with a wingspan of 93 feet. The MD-88 is an impressive 148 feet long with a 108 foot wingspan.

      For people with a decent amount of knowledge about commercial aviation, the easiest way to tell the difference is by what airline is operating it. For example, American Airlines only operates the MD-80 and AirTran now only operates the Boeing 717. As you become more involved in the aircraft spotting hobby, you quickly learn which airlines operate which types of aircraft. Delta, on the other hand, will soon operate the DC-9, MD-80, and 717. (So much for that method…)

      From the inside you can sometimes tell the difference by the seating layout. Delta’s MD-80′s have 3 seats on the left side of the aisle and 2 on the right, while its DC-9′s are the other way around. The 717′s cockpit is very unique and recognizable as compared to the other two.

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