Peer Review of the Federal Aviation Administration’s Study of the Effects of Passenger Seat Width and Pitch on Airplane Evacuation Performance

I was honoured to be invited by The National Academies of Sciences, Engineering, and Medicine (NASEM) of the U.S.A. to join an expert committee to critically review the US Federal Aviation Administration (FAA), Civil Aerospace Medical Institute (CAMI) report entitled, ‘Effects of Airplane Cabin Interiors on Egress I: Assessment of Anthropometrics, Seat Pitch, and Seat Width on Egress’ [1].  The CAMI study report published in 2021, set out to address whether seat pitch and width impact airplane evacuation.

The CAMI study was a response, in part, to the U.S. Congress directive that the FAA regulate seat dimensions to address concerns that airplane passenger seat space is becoming too small for the average American.  Sections 337 and 577 of the FAA Reauthorization Act of 2018, asked the FAA to issue regulations establishing minimum dimensions for passenger seats on aircraft, particularly if declining seat space can hinder emergency evacuations.  Following publication of the 2021 CAMI report, the FAA Reauthorization Act of 2024 (Section 365) again directed the FAA to regulate minimum seat dimensions.

In light of the 2024 Congressional directive, the FAA commissioned an independent expert review of its 2021 study to explore whether the results could be used to inform the pending decisions about whether to regulate the width and pitch of passenger seats.   NASEM was asked to determine if the study research methods, design, procedures and conclusions were appropriate and sound, including how tested individuals and passenger seat dimensions were selected given the anthropometric makeup of air travelers and actual seat dimensions in commercial airplanes.

The NASEM report on the CAMI study was independently peer reviewed ahead of its publication on the 1 July 2025 [2] and is publicly available at https://doi.org/10.17226/29070. 

Its main finding is that the CAMI study design, methodology, and analysis are deficient in several key aspects and so cannot support the study’s key conclusion that, 

“ ……  the experimental seat pitches, which are similar to the seat pitches currently found on flying commercial large transport category aircraft, should provide protection and not impede egress for 99% of the general U.S. population.”

A significant shortcoming of the study was that it was not designed to test CAMI’s central hypothesis [3] that,

 ‘….. As long as …….people can get into and out of the seat, the rate at which the passengers can move from their seats into the main aisle is ultimately immaterial to the evacuation flow as a whole.’

The CAMI study does not directly assess how seat width and pitch interact with passenger body size variables to affect evacuation performance, especially for plausible scenarios in which the number and distribution of people with large body sizes on a flight may not be typical of the flying public generally. 

Furthermore, given that the CAMI study was focused on understanding whether constrained seat space may impede evacuations for the purpose of informing its regulatory determinations, the findings from the NASEM review suggest that the study does not provide the information needed for this purpose.

The NASEM report goes on to suggest that with additional effort, valuable information can be extracted from the CAMI study data.  While there is unlikely to be sufficient data to support the central CAMI hypothesis, reanalysis of existing data may be useful in demonstrating that the hypothesis is invalid.  Furthermore, additional analysis of trial video footage could produce data relating to the time required by participants to exit their seat and seat row.   This could be used to correlate participant body size, seat width and pitch with seat row exit time.  Finally, an approach is suggested that combines data from a series of more inclusive and representative trials (including a wider range of participants in terms of age, body size, ability, etc.) with computer evacuation simulation to address the concerns raised by Congress.

REFERENCES: 

[1] Weed, D. B., Beben, M. S., Ruppel, D. J., Guinn, K. J., and Jay, S. M., (2021). Effects of Airplane Cabin Interiors on Egress I: Assessment of Anthropometrics, Seat Pitch, and Seat Width on Egress. DOT/FAA/AM-21/01.

https://www.faa.gov/sites/faa.gov/files/2022-04/Effects_of_Airplane_Cabin_Interiors_on_Egress_I.pdf.

[2] National Academies of Sciences, Engineering, and Medicine. 2025. Peer Review of the Federal Aviation Administration's Study of the Effects of Passenger Seat Width and Pitch on Airplane Evacuation Performance. Washington, DC: The National Academies Press. ISBN 978-0-309-73539-1. https://doi.org/10.17226/29070

Committee members and report authors: Nancy J. Currie-Gregg (Chair), Bruce Bradtmiller, Rory A. Cooper, Barbara M. Dunn, Edwin R. Galea, Rush F. Green,

[3] Weed, D. B., Beben, M. S., Ruppel, D. J., Guinn, K. J., (2019).  Effects of Airplane Seat Dimensions on Egress: Civil Aerospace Medicine Institute Submission to the Federal Aviation Administration Institutional Review Board.