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FAA Ignores Human Factors Science in Tests Related to New Reduced Size Seats

The long fight between the airline industry/FAA juggernaut and passengers regarding the Incredible Shrinking Seat Problem (ISSP) is being explored in a new study run by the FAA that apparently does not follow the rigorous science behind human body size variation (physical anthropometry) and study design. It turns out that there is a robust and complex science behind human body size and seat design which the FAA and airline industry has ignored for decades. The selection of a representative sample of passengers is at the core of reliable and scientifically valid human factors testing. This process involves screening and selection of passengers at the extreme ends of the user population based on percentile distribution analysis. Such individuals must be screened for physical and cognitive limitations in addition to physical body dimensions.

The test described by the Washington Post is a prime example of how human factors science has been increasingly ignored by commercial aircraft manufacturers and the airline industry at large. There is now ample evidence that commercial aircraft development is pushing aside as much professional human factors research as possible in the interest of reducing costs and increasing passenger load values. Not only is there serious human factors science missing from seating systems design it is also missing from cockpit/pilot interaction design. The staggering human factors oversights of the Boeing 737 MAX MCAS is but one systemic example of human factors science oversight. Without a properly designed human factors analysis applied to the current and projected seat size-reduction plans, we will soon reach a crisis where certain percentile individuals will not be able to travel in coach class…period.

It is interesting to note that the recent FAA interim report on the 737 MAX problems stated that going forward more rigorous human factors science in the design of cockpit automation and related flight control systems would be required. This is a curious directive from the FAA given that human factors engineering as a formal development discipline was first implemented in aircraft cockpit design and related aviation systems. HFE started in the cockpit…now it cannot be found in passenger seats much less the flight deck.

The airline seat design problem is driven by a profit-centered vs. user-centered strategy. After having worked in this space it is my opinion that nothing changes in a meaningful way without a major disaster or new legislative oversight. In this industry, the former drives the latter.

This is exactly the same problem now faced by Boeing with the 737 MAX MCAS where ignoring professional human factors science and performance criteria now leave the FAA with no option but to demand a retrace of the entire 737 MAX flight domain interface. This is very likely the dialogue taking place between Boeing and the FAA as the MAX gather dust by the hundreds. Anything less than a full retrace of the flight domain interfaces for the MAX will leave other human factors oversights and shortcuts lurking in the millions of lines of code and wonky sensor logic of the MAX. Compared to the seat size problem the MAX flight domain interface is acute while seat size is chronic impacting millions of travelers every day. They are both a function of ignoring human factors science during development.

The MAX problems have already cost Boeing untold brand value and actual market equity. One can ignore professional human factors research in simple problems where human skill acquisition can fumble through a confusing interface but there is no way that the seat size problem or the MAX MCAS interface can be solved without real HFE science.

Charles L. Mauro CHFP / President / MAURO Usability Science (Founded 1975) Cmauro@MauroUsabilityScience.Com

Additional Examples of HFE Science oversight in the utilization of incorrect user populations for product and system design. These have been pulled from our HFE research database or sent by colleagues.

Airline Bathroom Space Is Shrinking: https://www.wsj.com/articles/youre-not-getting-bigger-the-airplane-bathroom-is-getting-smaller-1535553108

NTSB Crash Dummy HFE Science Problems: https://www.consumerreports.org/car-safety/crash-test-bias-how-male-focused-testing-puts-female-drivers-at-risk/

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