I think there might be some confusion here. The vertical stabiliser (not the tail) was extended by 40 inches [0] to combat concerns about poor yaw control.
Although the Wikipedia article cites the UK ARB as the influence, it was also in response to the 1959 crash [1] of a 707 being used for training, in which Dutch roll was induced and later became so violent it ripped 3 engines off the wings.
Although the Wikipedia article cites the UK ARB as the influence, it was also in response to the 1959 crash [1] of a 707 being used for training, in which Dutch roll was induced and later became so violent it ripped 3 engines off the wings.
[0] https://en.wikipedia.org/wiki/Boeing_707#707-420
[1] https://en.wikipedia.org/wiki/1959_Washington_Boeing_707_cra...