2 Engines on the Tail

There are two kinds of jets with their engines on the tail: regular jets and regional jets. Regional jets such as the Canadair Regional Jet (CRJ) and Embraer Regional Jet (ERJ) can only seat 50 or 70 passengers and get their name because their short distance range only allows them to operate within a certain region of the country. The regular size jets are the Douglas DC-9, McDonnell-Douglas MD-80 & MD-90, and Boeing 717 which are all extremely similar and based on the same design. Place your mouse over the red links below to see the illustration highlighted.

Background

The DC-9 was one of the most popular aircraft built. Douglas built 976 of them between 1965 and 1980. Today there are only around 30 remaining in service worldwide, about 20 of them with Mexican cargo airline Aeronaves TSM.
The MD-80 is actually a generic name for the DC-9-81 and subsequent models MD-82, MD-83, MD-87,and MD-88. The MD-80 model continued where the DC-9 left off and remained in production until the last order was delivered to American Airlines on December 28, 1999. Out of 1,194 built only 123 remain in service as of June 2024; the largest number (15) with Aeronaves TSM in Mexico. The only airlines that operate the MD-80 in North America are World Atlantic with 6 of them based out of Miami and USA Jet with 8.
The MD-90 was built from 1994 until 1999, 117 in all. Delta was the only operator of the MD-90 and retired them in June 2020.
Boeing’s 717 program began development as the “MD-95” and entered service in 1999. Production ended in 2006. 155 were built and as of July 2024 there are 106 still in service with three airlines: Delta (80), Hawaiian Airlines (19), and QantasLink (7).
Bombardier of Canada began producing the Canadair Regional Jet in 1992 with the 50 seat CRJ-100 & CRJ-200 versions. These went out of production in 2006 after 1,021 were built, having been replaced by the CRJ-700 & 900 series which carry more passengers (78/90/100) in a more comfortable cabin. Production stands at around 2,000 of all versions and is slated to end by 2021 as Bombardier exits the commercial airliner business. Mitsubishi Heavy Industries in Japan has taken over service and support of these aircraft. The largest operator of CRJ aircraft is Skywest but most of the regional airlines in America fly them.
The Embraer Regional Jet entered service in 1997 and production ended in 2020 with over 1,200 built. In 2024 the largest operators of the ERJ are U.S. regional airlines Piedmont and CommutAir.

What to Look For

McDonnell Douglas DC-9

There are 5 different versions of the DC-9 and all differ in length. What sets the DC-9 apart from some MD-80s and all MD-90 and 717 models is the pointed shape of the tailcone. The DC9 has 2 baggage compartment doors on the lower right side of the fuselage.

There are 5 different versions of the DC-9 and all differ in length. What sets the DC-9 apart from some MD-80s and all MD-90 and 717 models is the pointed shape of the tailcone The DC9 has 2 baggage compartment doors on the lower right side of the fuselage.

McDonnell Douglas MD-80

The MD-80 series can be recognized by the wedge shape of its tailcone.

Also, all MD-80 & MD-90 aircraft have small horizontal fins on either side of the fuselage under the cockpit (not shown in the illustration) which are called “strakes”. This helps improve aerodynamic stability.

The MD-80 series can be recognized by the wedge shape of its tailcone Also, all MD-80 & MD-90 aircraft have small horizontal fins on either side of the fuselage under the cockpit (not shown in the illustration) which are called “strakes”. This helps improve aerodynamic stability.

The MD-80 series can be recognized by the wedge shape of its tailcone. Also, all MD-80 & MD-90 aircraft have small horizontal fins on either side of the fuselage under the cockpit (not shown in the illustration) which are called “strakes”. This helps improve aerodynamic stability.

McDonnell Douglas MD-90

The main difference in the MD-90 is its engines – larger and more tapered appearance than the earlier models. DC-9 and MD-80 aircraft are powered by Pratt & Whitney while these MD-90 engines are the IAE V2500, the most powerful engine to be mounted to the tail of an aircraft.

All MD80 & MD90 aircraft have 3 baggage compartment doors on the lower right of the fuselage and the MD-90 is the longest of all these jets.

The main difference in the MD-90 is its engines – larger and more tapered appearance than the earlier models. DC-9 and MD-80 aircraft are powered by Pratt & Whitney while these MD-90 engines are the IAE V2500, the most powerful engine to be mounted to the tail of an aircraft.

All MD80 & MD90 aircraft have 3 baggage compartment doors on the lower right of the fuselage and the MD-90 is the longest of all these jets.

The main difference in the MD-90 is its engines – larger and more tapered appearance than the earlier models. DC-9 and MD-80 aircraft are powered by Pratt & Whitney while these MD-90 engines are the IAE V2500, the most powerful engine to be mounted to the tail of an aircraft.

All MD80 & MD90 aircraft have 3 baggage compartment doors on the lower right of the fuselage and the MD-90 is the longest of all these jets.

Boeing 717

The Boeing 717 is shorter and its engines are longer than an MD-90 and much larger than an MD-80/DC-9. The engines are made by BMW/Rolls-Royce. On most 717s, there will be a title “Boeing 717” either on the front near the door or on the engine cover so it is pretty obvious which is the 717.

Canadair Regional Jet (CRJ)

The CRJ & ERJ are much smaller than any of the jets above and can be found at most airports in America today. The most obvious difference is that all CRJs have wingtip extensions called "winglets" while only one ERJ model has them – the 145XR version, flown by United Express.

The main differences between the older version (top) and the newer one (bottom) are length and seating capacity. Also, the newer CRJ versions have a pointed "tailcone" housing the APU exhaust similar to the ERJ.

The CRJ & ERJ are much smaller than any of the jets above and can be found at most airports in America today. The most obvious difference is that all CRJs have wingtip extensions called "winglets" while only one ERJ model has them – the 145XR version, flown by United Express.

Embraer Regional Jet (ERJ)

The ERJ has a few features that set it apart from a CRJ. The nose is longer and more pointed; the tailcone is pointed (that’s actually the Auxiliary Power Unit exhaust); and the engines are longer.

Cabin Layout

DC9 / MD80 / MD90 / 717

The cabins of the DC-9/MD-80/MD-90 and 717 aircraft are similar but there are a couple of major differences.

The DC-9 and 717 have one galley in the front and two lavatories at the rear. The MD-80 & MD-90 have two galleys, front and rear as shown in the seat map to the right. The rear galley is 3 rows up from the back and there is a door, which you can see in the illustration above.

The seating configuration is either 2×3 or 3×2 (MD-88 shown in the illustration). EXCEPTION: the MD-87 only is configured like a DC9 except that the row over the wing where the exit is only has one seat on the left and two on the right.

In all of these aircraft, the last three rows will not have a window view because it is blocked by the jet engine.

CRJ & ERJ

Seating maps are shown for the Canadair & Embraer Regional Jets below.

The CRJ (left) has two across seating, while the ERJ (right) has one left, two right seating. There are a few variants of the CRJ model with a capacity of 50 or 70 passengers; the CRJ-900 model has a first-class seat secion.

Both have one galley (G) and lavatory (L) as shown, but the CRJ-900 model adds an extra for the first class passengers.