I came across an article online that mentioned there is a landing gear between the left and right main landing gears of the MD-11. This landing gear is generally extended during takeoff and landing. However, when the aircraft is empty, this landing gear does not need to be deployed. The remaining landing gears are sufficient to absorb the impact upon landing, so doing this can reduce tire wear, serving to save on maintenance costs.

Additionally, back when JAL used the DC-10-40, they sometimes deliberately did not lower the center main landing gear during domestic flights. After all, domestic flights have lower takeoff weights and carry less fuel.

I haven’t been lucky enough to capture such a rare situation, but if I have the chance in the future, I will definitely take a picture.

Looking at the photo on hand, you can see the standard 3 main landing gears of the MD-11. The left and right landing gears have 4 wheels, while the center one has 2 wheels.

Next, I looked for the center main landing gears of other aircraft types. After all, only large multi-engine aircraft possess them; aside from the DC-10 and MD-11, there are only the B747, A340, and A340.

Viewing Swiss International Air Lines’ A340-300 from the side, this model’s center landing gear has 2 wheels, making it the most similar in form to the MD-11. Perhaps it looks clearer from the rear of this SAS or the Finnair A340-300 below.

The second-generation A340-500/600 is 100 tons heavier than the first-generation 200/300, so the center landing gear was increased to 4 wheels. The photo below shows an Etihad Airways A340-500. Speaking of which, only 34 units of this model were produced, making it quite rare in the Airbus family.

Moving on to the Boeing 747, the heavyweight champion, the center landing gear was increased to two units. Each landing gear truck also has 4 wheels.

Of course, the giant A380 goes without saying; with its dual center landing gear configuration similar to the 747, however, each landing gear truck has been increased to 6 wheels!

As it is now the era where twin-engine aircraft reign supreme and three-engine and four-engine aircraft are fading away—for instance, Air France’s last 747 will be retired tomorrow, January 14th—opportunities to see center main landing gears will become fewer and fewer. It is truly a bit sentimental.