14 CFR 91.705 - Operations within airspace designated as Minimum Navigation Performance Specification Airspace.
(a) Except as provided in paragraph (b) of this section, no person may operate a civil aircraft of U.S. registry in airspace designated as Minimum Navigation Performance Specifications airspace unless -
(1) The aircraft has approved navigation performance capability that complies with the requirements of appendix C of this part; and
(2) The operator is authorized by the Administrator to perform such operations.
(b) The Administrator may authorize a deviation from the requirements of this section in accordance with Section 3 of appendix C to this part.