By Bjorn Fehrm
04 September 2015, © Leeham Co: One of the hottest areas of modern airline aviation is the passenger experience and especially the seating. There are people who are specialists on the subject like Runway Girl Network; I will not try to duplicate their work here on my Corner. But I follow the subject in detail as it touches on our work of creating apples-to-apples airline comparison conditions, our Normalized cabins or LOPAs as its also called (Layout Of Passenger Amenities).
As I observe the debate on more and more cramped economy seating, I can’t but feel the whole debate is revolving around the wrong dimensions. The debate is focusing on seat width but it is a seat width which is not the primary one that affects a passenger’s comfort. Before being accused of trying to confuse with facts, let me explain.
How seats are measured
To understand what would be a better measurement of comfort than today’s seat width, let’s look at how a seat for a single aisle or a dual aisle aircraft is made and measured. Figure 1 shows the most common type, the one that is used in the single aisles and the nine abreast new twins. It combines three seat cushions/backs with four armrests into a seat triplet.
The confusion starts with the seat measurement which is used in the industry to denote seat width. It is the seat cushion width, the measurement A in Figure 1. But what everyone complains about is the rubbing of shoulders, which is dependent on measurement B.
Measurement B, what I will call the “seating width,” includes part of the armrests for each passenger. The standard way of making a seat triplet with, say, 17 or 18 inch seat cushions is to combine that with four armrests, each measuring two inches wide. As long as the armrests stay at the standard two inches one could use today’s measurement, as the important shoulder width scales with the cushion width.
But they don’t. Marketing has gotten hold of seating and told the cabin people they want the magic mantra of “our seats are 18 inches” to communicate to the public and customers. The result is more and more configurations with 18 inch seat cushions paired with one-and-a-half or even one inch armrests. The triplet takes only 58 or 60 inch width instead of the normal 62, but they sure are “18 inch seats.”
By now it should be clear the debate is discussing the wrong thing. Seat width should be about seat shoulder width and the marketers bragging about 18 inch seats would have to concede that “our seats have (only) 19 inch seat shoulder width”. But it doesn’t stop there. The seats we have today are un-equal as well; the designs need to change to give each passenger equal lateral living space.
Equal passenger comfort
The middle passenger in a triplet gets less living space. He gets 1 + 17 +1 =19 inch “seating width” if the armrests are share amicably. The window passenger gets 1 + 17 +2 and the aisle passenger gets 2 + 17 + 1, Figure 1. This means both get 20 inch seating width. These passengers also have the benefit of additional free space at the window and aisle. So things are very un-equal in today’s standard seats.
What would be needed is a triplet offering 20 inches to all three passengers with 17 inch seat cushions or 21 inches with 18. This would mean the central armrests should be minimum 2.5 inches each with the outer at two inch. With 17 inch seat cushions, this gives 60 inch triplets; with 18 inch cushions, the results is 63 inches. Even with the dreaded 17 inch cushions, this gives each passenger 20 inch seating width (i.e. shoulder space), the same as today’s 18 inch seats gives the least fortunate passenger.
This all ignores other measurements which are important, like set pitch (distance between seat rows); this is of course equally important.
Today’s seat comfort discussion is a hot topic, too hot to be conducted with the wrong arguments.
Reading the trip reports it is clear that what matters to passengers in cramped economy seats is more shoulder-to-shoulder space than not getting the bum to fit the seat cushion. I would venture that the seat pitch is also more important than if the seat cushion is 17 or 18 inches as long as 20 inches of shoulder width would be provided.
We can conclude that there are probably two measurements which are more important than the one used in today’s seating debate. It’s time to change the argumentation to the right measurements.