14 CFR §420.25

1. (a)If a flight corridor or impact dispersion area defined by § 420.23 contains a populated area, the applicant shall estimate the casualty expectation associated with the flight corridor or impact dispersion area. An applicant shall use the methodology provided in appendix C to this part for guided orbital or suborbital expendable launch vehicles and appendix D for unguided suborbital launch vehicles.
2. (b)For licensed launches, the FAA will not approve the location of the proposed launch point if the estimated expected casualty exceeds 1 × 10−4.