What is comfort

Image: Óscar Matamora

APEX Insight: How do you design for passenger comfort within the confines of an aircraft cabin? Four design experts offer their insights.

I once asked three designers to draw their ideal version of an airline seat, and what I got back was three designers’ ideal versions of an airline seat. Sure, there were similarities: They all had backrests, seat pans, armrests and padding – which is good because most seat users have backs, legs, arms and bones – but that’s where the commonalities ended (for the chairs, not the seat users). Of course, most seat users also have thoughts and feelings, and that’s where the problem begins, since very few of us are like-minded when it comes to defining, let alone designing, comfort.

“I have always regarded comfort as a state of mind,” says Tom Eaton, director of Design for LIFT by EnCore. “It is not something that can be easily quantified or identified.” Flavia Renata Dantas Alves Silva Ciaccia, engineer of Comfort and Ergonomics at Embraer, defines comfort “not as the absence of discomfort, but as a positive feeling of well-being and pleasure.” The sentiment is echoed, with slight variation, by Blake Emery, director of Differentiation Strategy for Boeing, who describes comfort as “an absence of worrisome attention combined with a sense of peaceful well-being.”

“I have always regarded comfort as a state of mind.” — Tom Eaton, LIFT by EnCore

Mark Hiller, chief executive officer of Recaro Aircraft Seating, breaks it down even further: “Perceived comfort is in fact always an interaction between two aspects: First, individual preferences associated with convenience and well-being … and second, physiological and biomechanical factors.” Comfort, then, is the absence of discomfort; but it is not only that, it is something better. In other words, comfort is complicated.

Discomfort Is a State of Body

Discomfort, however, is pretty straightforward. “Oddly, discomfort is more definable [than comfort], as it presents itself as a clear pain point,” Eaton says. “We were assessing the living space of a new prototype that had been modified to improve its comfort,” he recalls. “To our surprise, it felt worse; but we knew we had theoretically made it better through increasing the amount of space we were giving the passenger.” Perplexed, Eaton and his team observed the situation more closely and noticed that when people stretched their legs, they now came into contact with a small edge on the seat in front of them. “We learned from this that it is not simply the additional inches that matter, but also the subtle nature of surfaces that define that space,” he says.   

As the fairy tale goes, despite sleeping on 20 feather mattresses, the princess still felt the pea. “Physiological and biomechanical factors are always dominant, and therefore have to be eliminated first,” Hiller explains. There are some general principles to start with in that regard. “For example, if pitch falls below a certain point, we can predict that no one will be happy,” Emery says.

“There are some objective measures for predicting seat discomfort.” — Flavia Renata Dantas Alves Silva Ciaccia, Embraer

Thresholds based on anthropomorphic reference data are commonly used to provide guidelines on the necessary requirements for knee space, legroom, seat width, egress and so forth. Recaro, and most of the design community, works around parameters to accommodate a broad range of users, starting with the fifth percentile female (roughly 5′, 110 pounds) and ending with the 95th percentile male (around 6’2″, 216 pounds).

“There are some objective measures for predicting seat discomfort, such as pressure mapping, activity analysis and some physiological measures,” Ciaccia says. But all agree that the most effective way to eliminate discomfort is through trial and error.  

Going to Extreme Measures

“The best processes to evaluate comfort are the ones that have a holistic approach and elements of context, human characteristics and product design,” Ciaccia says. In 2008, Embraer opened a Comfort Engineering Centre in São Paulo in partnership with
the Federal University of Santa Catarina and the Federal University of São Carlos. The center holds two full-size mock-ups of Embraer 170 and 190 cabin sections, both designed to simulate in-flight conditions.

“The project generated tools and models for evaluating comfort and developing interiors focusing on user experience,” Ciaccia says. “We could understand how passenger comfort perception is affected by the combination of different cabin environments.” One notable finding Ciaccia’s team uncovered through mock-up experiments was that the sense of discomfort is reduced when a person is focused on an activity of interest to the individual. A recent study published in 2015 by TU Delft researcher Suzanne Hiemstra-van Mastrigt also found that backseat passengers in a car felt significantly more fit and refreshed after playing an active game.

“We could understand how passenger comfort perception is affected by the combination of different cabin environments.” — Flavia Renata Dantas Alves Silva Ciaccia, Embraer

“At Boeing, we lean toward controlled experimental methods,” Emery says. In 2002, Boeing opened its Passenger Experience Research Center in Everett, Washington, where a mock-up enables Emery and his team to gauge participants’ perceptions of different cabin attributes. “Knowing how to ask questions is very important,” he notes. “For example, if I ask the subjects to rate their satisfaction with a seat cushion, the very question causes their attention to shift. They may then decide the seat cushion is uncomfortable, whereas before I asked, everything was just fine.”

With several long-haul flights exceeding 15 hours, Hiller points out that duration is a critical factor in evaluations of seat comfort. Accordingly, that ethos led him to what some may view as extreme measures. In the development phase of the CL3710 long-haul economy seat, he asked his team to deliver a prototype to his home. He spent three nights and one whole day in the seat. “The product experience was superior, but the purser service could have been optimized,” he quips.

Comfort Is a State of Mind

Service, despite having nothing to do with the physical characteristics of a seat, can play a major role in perceptions of comfort. A 2012 study conducted by Peter Vink, professor of Environmental Ergonomics and head of TU Delft’s Design Engineering department, and his colleagues found that variables such as “rude flight attendants and bad hygiene” have the ability to “reduce the comfort experience dramatically.” The research even finds that a flight delay would predispose passengers to rate their comfort level negatively. “A pain in the neck” may be less idiomatic than it seems.

Judgment plays a big role in informing perceptions of comfort. “A few years ago, I was involved in the development of a modular economy-class seat for aircraft,” Emery recounts. “During the user testing of about the third prototype, we discovered that nobody wanted to sit in the seat to test it because it looked uncomfortable. Once they sat in it, they discovered it was quite comfortable, but they had to overcome their original rejection of the seat appearance.”

“Nobody wanted to sit in the seat to test it because it looked uncomfortable.” — Blake Emery, Boeing

So, what does a comfortable seat look like? “We are seeing an interesting shift on this topic,” Eaton says. “Historically, people have considered thick plush cushions, real leather and wood laminates as comfortable and cozy; but if you look at modern furniture today, it relies more and more on thin, lightweight structures, and smart, often knitted, fabrics that have the ability to morph or comply unexpectedly.” Indeed, a resurgence of Scandinavian-influenced minimalism, made popular by IKEA, has broadened the appeal of functional design. “This awareness is now entering our industry, and passengers are no longer looking for [the] classic indicators – which are, in fact, unsuited to the space and weight requirements of aerospace. They are looking instead for signs of innovation,” he says.

A flight delay or an ugly seat can negatively influence a passenger’s comfort experience, but perceptions can be influenced positively, too. In 2011, Norwegian Air Shuttle was already flying a fleet of Boeing 737NGs and had just taken early delivery of additional 737 aircraft – only these were outfitted with the Boeing Sky Interior (BSI). Boeing and the airline used the opportunity to evaluate the perceived difference among passengers. The results were illuminating: Despite having the exact same seats and the exact same amount of space, passengers reported being more comfortable on BSI-equipped aircraft. In fact, passengers with 29-inch pitch seating on a 737 with BSI were more comfortable than those with 31-inch pitch seating on the 737NG aircraft. 

One thing we can probably all agree upon is the fact that comfort is hard to agree upon. Anyone who’s shared a bed with someone knows this. That may sound like cold comfort for designers, but in fact, it’s the space in between that’s the providence of design. 

“What Is Comfort?” was originally published in the 7.2 April/May issue of APEX Experience magazine.

Katie is a writer for APEX Media, based in Toronto, Ontario.