14 CFR § 25.815 - Width of aisle.
The passenger aisle width at any point between seats must equal or exceed the values in the following table:
|Passenger seating capacity||Minimum passenger aisle width (inches)|
|Less than 25 in. from floor||25 in. and more from floor|
|10 or less||1 12||15|
|11 through 19||12||20|
|20 or more||15||20|
1 A narrower width not less than 9 inches may be approved when substantiated by tests found necessary by the Administrator.
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