Thomey-General Dynamics 2010

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U.S. Department of Transportation Federal Aviation Administration SEP 1 0 2010 Mr. Gary Thomey Chief Pilot General Dynamics 23800 Wind Sock Drive, Hanger D Dulles, Va. 20166

Dear Mr. Thomey:

Office of the Chief Counsel 800 Independence Ave ., S.W.

Washington, D.C. 20591 This letter is in response to your May 8, 20 l 0 request for interpretation of 14 C.F.R. § 91.17 5. You asked whether a pilot may operate an aircraft below a published decision height (DH) or minimum descent altitude (MDA) if the pilot has the runway in sigh~ but the runway visual range (RVR) is reported at less than the published minimum RVR for the approach.

Section 91.175 establishes the conditions that must be present for a pilot to continue operations below decision altitude (DA)/DH or MDA. One of the conditions is that the "flight visibility is not less than the visibility prescribed in the standard instrument approach being used ...." 14 C.F.R. § 91. l 75(c)(2). Another condition is that one of the visual references in the runway environment listed in the rule must be visible to the pilot See § 91.175(c)(3)(i)-(x). · In determining whether the pilot may operate below DA/DH or MDA, for purposes of § 91. l 75(c), the flight visibility is controlling. See Legal Interpretation to Larry K. Johnson, from David L. Bennett (Mar. 10, 1986) (addressing this requirement then codified as§ 91.116); see also 46 Fed. Reg. 2280, 2282 (Jan. 8, 1981) (revising the rule to "make it clear that the visibility referred to is the visibility from the aircraft."); Administrator v. Davey, NTSB Order No. EA-1531 (Dec. 12, 1980) ("[C]ontrolling visibility is not ground visibility, as reflected by the RVR values, but rather flight visibility, as measured from the cockpit of the aircraft."). In your letter you note that the pilot "has the runway in sight." Accordingly, the pilot may continue the approach below the authorized DA/DH or MDA because the pilot has determined the flight visibility and the runway, one of the enumerated visual references in§ 91.175(c)(3), is in sight. See§ 91.175(c)(3)(ix). The pilot must maintain this flight visibility from descent below MDA or DA/DH until touchdown. 46 Fed. Reg. 2282.

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This response was prepared by Dean Griffith, Attorney in the Regulations Division of the Office of the Chief Counsel, and was coordinated with General Aviation and Commercial Division of Flight St~dards Service. Please contact us at (202) 267-3073 if we can be of further assistance.

Sincerely, ·

Rebecca B. MacPherson Assistant Chief Counsel for Regulations, AGC-200