Apart from the extra fuel tanks of the MD
-83,the only differences between an MD
-81-82 and -83,are the certified weights.There are two options re. engines for these planes:JT8D-217A,-217C and -219.The -219 has more power than the 217A/C and can be fitted to -81's and -82's,as well.These planes were originally supplied with the pointed tail cone and analogue cockpit instruments.Starting in 1986,the beaver tailcone and EFIS instruments were introduced on the production line.All SAS MD
's previously delivered,were converted with the tail cone and glass cockpit (18 a/c) and,consequently,all SAS MD
's now have the beaver tail and EFIS cocpit.Other operators had the option to convert their planes.The beaver tail reduces drag by some 1.5-3 %,depending on center of gravity location.
There were no MD
-84,-85 or -86.Next model was the MD
-87 (DC-9-87 it says on our,SAS,data plates).217C engines,with -219 an option,longer strakes on the engine nacelles and a taller tail fin to compensate for a shorter fuselage.All but the very earliest planes have the service door between the left wing and engine deleted.Beaver tail and EFIS cockpit was standard.Could be certified at two different take-off weights,one or two auxiliary tanks was an option,too.
-88 was certified as such.High weights,-219 engines and glass EFIS cockpit.It also had the possibility to be modified with prop-fan engines had these become certified.
-89,next was the MD
-90-30.SAS data plates state MD
-90,not DC-9-90.Fuselage stretch compared to MD
-81,82,83 and 88.New,larger engines (V2500D),tall fin of the MD
-87 and fully hydraulic elevator controls.There are also a range of other,internal differences in electric systems,etc.The MD
-90 was offered with the EFIS cockpit initially,later production planes had a "true glass cockpit",MD-11-style layout.
-95 (now Boeing 717-200) was basically a DC-9 in many ways;fuselage length somewhere between the DC-9-40 and -50,DC-9-30/40 wing (albeit of newer production standards),new engines,MD-87/90 style empennage and more or less completely new systems inside.The aft,ventral stairway isn't even an option on this model.MD-11-style glass cockpit.Cockpit "eye brow" windows deleted at a later stage.