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Douglas DC-9 & McDonnell-Douglas MD-80/MD-90 series

The DC-9 was the start of a long series of aircraft, strongly varying in length and also engine types, ultimately ending with the MD-90. It was the first twin jet airliner in the west with a T-tail and engines attached to the rear fuselage. Its nose is based on the DC-8, without the air intakes below the nose but with a single eyebrow window on each side. Other features are small, slender wings, a double bubble fuselage cross section and an air intake at the base of the vertical stabiliser.

The forward fuselage of the DC-9 and later versions is based in the DC-8. They retain the eyebrow windows but don't have air intakes at the bottom of the nose.

This photo shows the slight double bubble fuselage, starting after the first cabin door, with the junction just above the wings. Also note the air intake in the root of the vertical stabiliser.

The wings of the DC-9 are quite small and slender for this size of aircraft, in particular on the MD-80 and MD-90.

Different versions

How to recognise the different versions of the DC-9, MD-80 and MD-90 will be added later.

Confusion possible with

Boeing 717

b717

This aircraft started its life as MD-95 so it is obvious that you can confuse it with a DC-9, MD-87 or maybe another from the family. The Boeing 717 is best recognised by the shape of the engine nacelles. It also has the flat tail cone of the later MD-80 series and an MD-87 like tail.

Comac ARJ21 

arj21

This Chinese regional jet also looks like a small DC-9 or MD-87, because the MD-80 and MD-90 were built in license in China. Likely a lot of manufacturing tooling was reused. Most obvious differences are the disappearance of the eyebrow windows and the high bypass engines on the ARJ21.

Fokker F28, Fokker 70/100 

fokker 70

Especially the shortest versions of the DC-9 could be confused with the F28, as both have an eyebrow window. However, the Fokkers have a blunt tail cone, that can be opened as air brake, and a large dorsal fin.