Why do commercial aircraft have two or more engines? Why do airlines not operate single-engine aircraft for short-haul routes or low-demand areas? Let’s explore the paradox of commercial single-engine jet aircraft.
Is there a commercial jet with a single jet engine?
You only need to look at the army to see what is possible with a single jet plane. Air forces around the world have multiple fighter jet designs that can fly as fast as a single jet engine Concorde and are much simpler to repair and engineer.
However, when you look at commercial passenger aircraft (such as those from Boeing and Airbus), there is no single-jet engine aircraft. Well, almost none.
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The Cirrus Vision SF50, which hit the market in 2016, was the world’s first single-jet civil aircraft. It can carry seven passengers up to a range of 600 nautical miles (690 mi, 1,100 km). It’s not very fast, just 300 knots (350 mph, 560 km / h) maximum cruising, which is about half the speed of a typical commercial jetliner.
So while we certainly have the know-how to build a single-engine airplane and engines powerful enough to allow an airplane as large as the Boeing 737 to fly, why don’t they exist?
It turns out that there are some problems with the single-engine concept.
Problems with a single motor
There are few problems with the single-engine jet concept beyond light aircraft:
- A single engine would need to be placed at the rear of the aircraft (not on the wings) and would take up valuable cabin space. Airlines are already struggling to accommodate enough passengers, and putting non-revenue-generating machinery in their place would be a step backwards.
- A large engine needs clearance between the fuselage and the engine itself; otherwise there would be more resistance. The higher the engine is mounted, the more engineering and maintenance issues (such as the third engine in the trijet)
- Passengers in the back of the plane would be right under the engine and would find it very loud and uncomfortable.
- The plane would be heavy in the rear, making tail blows a greater risk
And we haven’t even mentioned security issues.
FAA regulation
Surprisingly, despite all of the above reasons for not building a single-engine aircraft, it cannot be denied that the costs to develop and operate such an aircraft would be cheaper.
However, there are some safety factors to consider, especially for an aircraft with 100-200 passengers.
According to the FAA, there cannot be a single point of failure when it comes to aircraft. Every plane needs at least two of everything from wheels to pilots to engines, to make sure there is any loss, the plane can continue to fly.
For each installation of the power plant and auxiliary power unit, it must be established that no failure or malfunction or probable combination of failures will jeopardize the safe operation of the aircraft, except that failure of the structural elements need not be considered if the probability of such failure is extremely remote. – FAA regulation
These regulations are in effect because some of the earliest commercial aircraft (such as the Junkers F-13 and Fokker FII) had a single engine and had a much higher probability of accidents.
Finally, we must consider the ETOPS classifications. If a plane has a single engine, the FAA (or any aviation authority) is unlikely to allow it even near a bathtub, let alone fly over an ocean. An airplane needs two engines to make sure it can get to the next runway if one fails.
As for the personal Cirrus Vision SF50 presented at the beginning of this article, they actually have a parachute included in the fuselage that allows the plane to float safely in the event of engine failure.
What you think? Would you fly in a single-engine commercial aircraft? Let us know in the comments.
