Except in an emergency, or if otherwise necessary for safety of flight, or unless otherwise authorized by the Flight Standards District Office for a purpose listed in 93.309, no person may operate an aircraft in the Special Flight Rules Area at an altitude lower than the following:

(a) Minimum sector altitudes -- (1) Commercial sightseeing flights -- (i) Marble Canyon Sector. Lees Ferry to Boundary Ridge: 6,000 feet MSL.

(ii) Supai Sector. Boundary Ridge to Supai Point: 7,500 feet MSL.

(iii) Diamond Creek Sector. Supai Point to Diamond Creek: 6,500 feet MSL.

(iv) Pearce Ferry Sector. Diamond Creek to the Grand Wash Cliffs: 5,000 feet MSL.

(2) Transient and general aviation operations -- (i) Marble Canyon Sector. Lees Ferry to Boundary Ridge: 8,000 feet MSL.

(ii) Supai Sector. Boundary Ridge to Supai Point: 10,000 feet MSL.

(iii) Diamond Creek Sector. Supai Point to Diamond Creek: 9,000 feet MSL.

(iv) Pearce Ferry Sector. Diamond Creek to the Grand Wash Cliffs: 8,000 feet MSL.

(b) Minimum corridor altitudes -- (1) Commercial sightseeing flights -- (i) Zuni Point Corridors. 7,500 feet MSL.

(ii) Dragon Corridor. 7,500 feet MSL.

(2) Transient and general aviation operations -- (i) Zuni Point Corridor. 10,500 feet MSL.

(ii) Dragon Corridor. 10,500 feet MSL.

(iii) Tuckup Corridor. 10,500 feet MSL.