Federal Aviation Administration, DOT § 91.179 approaches without vertical guidance; that when ground obstructions inter- and vene, the point beyond which that (iii) The displayed imagery and air- higher minimum altitude applies shall craft flight symbology do not adversely be crossed at or above the applicable obscure the pilot’s outside view or field MCA. of view through the cockpit window; [Doc. No. 18334, 54 FR 34294, Aug. 18, 1989, as (3) The EFVS includes the display amended by Amdt. 91–296, 72 FR 31678, June element, sensors, computers and power 7, 2007] supplies, indications, and controls. It may receive inputs from an airborne § 91.179 IFR cruising altitude or flight navigation system or flight guidance level. system; and Unless otherwise authorized by ATC, (4) The display characteristics and the following rules apply— dynamics are suitable for manual con- (a) In controlled airspace. Each person trol of the aircraft. operating an aircraft under IFR in [Doc. No. 18334, 54 FR 34294, Aug. 18, 1989, as level cruising flight in controlled air- amended by Amdt. 91–267, 66 FR 21066, Apr. space shall maintain the altitude or 27, 2001; Amdt. 91–281, 69 FR 1640, Jan. 9, 2004; flight level assigned that aircraft by Amdt. 91–296, 72 FR 31678, June 7, 2007; Amdt. ATC. However, if the ATC clearance as- 91–306, 74 FR 20205, May 1, 2009] signs ‘‘VFR conditions on-top,’’ that § 91.177 Minimum altitudes for IFR op- person shall maintain an altitude or erations. flight level as prescribed by § 91.159. (b) In uncontrolled airspace. Except (a) Operation of aircraft at minimum al- while in a holding pattern of 2 minutes titudes. Except when necessary for or less or while turning, each person takeoff or landing, no person may oper- operating an aircraft under IFR in ate an aircraft under IFR below— level cruising flight in uncontrolled (1) The applicable minimum altitudes airspace shall maintain an appropriate prescribed in parts 95 and 97 of this altitude as follows: chapter. However, if both a MEA and a MOCA are prescribed for a particular (1) When operating below 18,000 feet route or route segment, a person may MSL and— operate an aircraft below the MEA (i) On a magnetic course of zero de- down to, but not below, the MOCA, pro- grees through 179 degrees, any odd vided the applicable navigation signals thousand foot MSL altitude (such as are available. For aircraft using VOR 3,000, 5,000, or 7,000); or for navigation, this applies only when (ii) On a magnetic course of 180 de- the aircraft is within 22 nautical miles grees through 359 degrees, any even of that VOR (based on the reasonable thousand foot MSL altitude (such as estimate by the pilot operating the air- 2,000, 4,000, or 6,000). craft of that distance); or (2) When operating at or above 18,000 (2) If no applicable minimum altitude feet MSL but below flight level 290, is prescribed in parts 95 and 97 of this and— chapter, then— (i) On a magnetic course of zero de- (i) In the case of operations over an grees through 179 degrees, any odd area designated as a mountainous area flight level (such as 190, 210, or 230); or in part 95 of this chapter, an altitude of (ii) On a magnetic course of 180 de- 2,000 feet above the highest obstacle grees through 359 degrees, any even within a horizontal distance of 4 nau- flight level (such as 180, 200, or 220). tical miles from the course to be flown; (3) When operating at flight level 290 or and above in non-RVSM airspace, and— (ii) In any other case, an altitude of (i) On a magnetic course of zero de- 1,000 feet above the highest obstacle grees through 179 degrees, any flight within a horizontal distance of 4 nau- level, at 4,000-foot intervals, beginning tical miles from the course to be flown. at and including flight level 290 (such (b) Climb. Climb to a higher minimum as flight level 290, 330, or 370); or IFR altitude shall begin immediately (ii) On a magnetic course of 180 de- after passing the point beyond which grees through 359 degrees, any flight that minimum altitude applies, except level, at 4,000-foot intervals, beginning 729 VerDate Nov<24>2008 09:04 Mar 03, 2010 Jkt 220044 PO 00000 Frm 00739 Fmt 8010 Sfmt 8010 Y:\SGML\220044.XXX 220044 wwoods2 on DSK1DXX6B1PROD with CFR § 91.180 14 CFR Ch. I (1–1–10 Edition) at and including flight level 310 (such both before and during climb or de- as flight level 310, 350, or 390). scent. (4) When operating at flight level 290 [Doc. No. 18334, 54 FR 34294, Aug. 18, 1989, as and above in airspace designated as Re- amended by Amdt. 91–296, 72 FR 31679, June duced Vertical Separation Minimum 7, 2007] (RVSM) airspace and— (i) On a magnetic course of zero de- § 91.183 IFR communications. grees through 179 degrees, any odd Unless otherwise authorized by ATC, flight level, at 2,000-foot intervals be- the pilot in command of each aircraft ginning at and including flight level 290 operated under IFR in controlled air- (such as flight level 290, 310, 330, 350, space must ensure that a continuous 370, 390, 410); or watch is maintained on the appropriate (ii) On a magnetic course of 180 de- frequency and must report the fol- grees through 359 degrees, any even lowing as soon as possible— flight level, at 2000-foot intervals be- (a) The time and altitude of passing ginning at and including flight level 300 each designated reporting point, or the (such as 300, 320, 340, 360, 380, 400). reporting points specified by ATC, ex- cept that while the aircraft is under [Doc. No. 18334, 54 FR 34294, Aug. 18, 1989, as radar control, only the passing of those amended by Amdt. 91–276, 68 FR 61321, Oct. reporting points specifically requested 27, 2003; 68 FR 70133, Dec. 17, 2003; Amdt. 91– by ATC need be reported; 296, 72 FR 31679, June 7, 2007] (b) Any unforecast weather condi- tions encountered; and § 91.180 Operations within airspace designated as Reduced Vertical (c) Any other information relating to Separation Minimum airspace. the safety of flight. (a) Except as provided in paragraph [Doc. No. 18334, 54 FR 34294, Aug. 18, 1989, as (b) of this section, no person may oper- amended by Amdt. 91–296, 72 FR 31679, June 7, 2007] ate a civil aircraft in airspace des- ignated as Reduced Vertical Separa- § 91.185 IFR operations: Two-way tion Minimum (RVSM) airspace unless: radio communications failure. (1) The operator and the operator’s (a) General. Unless otherwise author- aircraft comply with the minimum ized by ATC, each pilot who has two- standards of appendix G of this part; way radio communications failure and when operating under IFR shall comply (2) The operator is authorized by the with the rules of this section. Administrator or the country of reg- (b) VFR conditions. If the failure oc- istry to conduct such operations. curs in VFR conditions, or if VFR con- (b) The Administrator may authorize ditions are encountered after the fail- a deviation from the requirements of ure, each pilot shall continue the flight this section. under VFR and land as soon as prac- ticable. [Amdt. 91–276, 68 FR 70133, Dec. 17, 2003] (c) IFR conditions. If the failure oc- § 91.181 Course to be flown. curs in IFR conditions, or if paragraph (b) of this section cannot be complied Unless otherwise authorized by ATC, with, each pilot shall continue the no person may operate an aircraft flight according to the following: within controlled airspace under IFR (1) Route. (i) By the route assigned in except as follows: the last ATC clearance received; (a) On an ATS route, along the cen- (ii) If being radar vectored, by the di- terline of that airway. rect route from the point of radio fail- (b) On any other route, along the di- ure to the fix, route, or airway speci- rect course between the navigational fied in the vector clearance; aids or fixes defining that route. How- (iii) In the absence of an assigned ever, this section does not prohibit ma- route, by the route that ATC has ad- neuvering the aircraft to pass well vised may be expected in a further clear of other air traffic or the maneu- clearance; or vering of the aircraft in VFR condi- (iv) In the absence of an assigned tions to clear the intended flight path route or a route that ATC has advised 730 VerDate Nov<24>2008 09:04 Mar 03, 2010 Jkt 220044 PO 00000 Frm 00740 Fmt 8010 Sfmt 8010 Y:\SGML\220044.XXX 220044 wwoods2 on DSK1DXX6B1PROD with CFR.