or
ENR 1.4 - 17
h. A landing aircraft will have priority over a departing aircraft if the latter cannot take off with prescribed separation standards.
I. An aircraft landing or taking off will be given priority over taxiing aircraft.
Doesn't mean the goose in the 172 was 'legal' to land though, it just means that if he had plowed into the Dash and killed everyone, the Dash pilots would have copped the blame in the subsequent investigation