background image

741 

Federal Aviation Administration, DOT 

§ 91.180 

for navigation, this applies only when 
the aircraft is within 22 nautical miles 
of that VOR (based on the reasonable 
estimate by the pilot operating the air-
craft of that distance); or 

(2) If no applicable minimum altitude 

is prescribed in parts 95 and 97 of this 
chapter, then— 

(i) In the case of operations over an 

area designated as a mountainous area 
in part 95 of this chapter, an altitude of 
2,000 feet above the highest obstacle 
within a horizontal distance of 4 nau-
tical miles from the course to be flown; 
or 

(ii) In any other case, an altitude of 

1,000 feet above the highest obstacle 
within a horizontal distance of 4 nau-
tical miles from the course to be flown. 

(b) 

Climb. 

Climb to a higher minimum 

IFR altitude shall begin immediately 
after passing the point beyond which 
that minimum altitude applies, except 
that when ground obstructions inter-
vene, the point beyond which that 
higher minimum altitude applies shall 
be crossed at or above the applicable 
MCA. 

[Doc. No. 18334, 54 FR 34294, Aug. 18, 1989, as 
amended by Amdt. 91–296, 72 FR 31678, June 
7, 2007; Amdt. 91–315, 75 FR 30690, June 2, 2010] 

§ 91.179

IFR cruising altitude or flight 

level. 

Unless otherwise authorized by ATC, 

the following rules apply— 

(a) 

In controlled airspace. 

Each person 

operating an aircraft under IFR in 
level cruising flight in controlled air-
space shall maintain the altitude or 
flight level assigned that aircraft by 
ATC. However, if the ATC clearance as-
signs ‘‘VFR conditions on-top,’’ that 
person shall maintain an altitude or 
flight level as prescribed by § 91.159. 

(b) 

In uncontrolled airspace. 

Except 

while in a holding pattern of 2 minutes 
or less or while turning, each person 
operating an aircraft under IFR in 
level cruising flight in uncontrolled 
airspace shall maintain an appropriate 
altitude as follows: 

(1) When operating below 18,000 feet 

MSL and— 

(i) On a magnetic course of zero de-

grees through 179 degrees, any odd 
thousand foot MSL altitude (such as 
3,000, 5,000, or 7,000); or 

(ii) On a magnetic course of 180 de-

grees through 359 degrees, any even 
thousand foot MSL altitude (such as 
2,000, 4,000, or 6,000). 

(2) When operating at or above 18,000 

feet MSL but below flight level 290, 
and— 

(i) On a magnetic course of zero de-

grees through 179 degrees, any odd 
flight level (such as 190, 210, or 230); or 

(ii) On a magnetic course of 180 de-

grees through 359 degrees, any even 
flight level (such as 180, 200, or 220). 

(3) When operating at flight level 290 

and above in non-RVSM airspace, and— 

(i) On a magnetic course of zero de-

grees through 179 degrees, any flight 
level, at 4,000-foot intervals, beginning 
at and including flight level 290 (such 
as flight level 290, 330, or 370); or 

(ii) On a magnetic course of 180 de-

grees through 359 degrees, any flight 
level, at 4,000-foot intervals, beginning 
at and including flight level 310 (such 
as flight level 310, 350, or 390). 

(4) When operating at flight level 290 

and above in airspace designated as Re-
duced Vertical Separation Minimum 
(RVSM) airspace and— 

(i) On a magnetic course of zero de-

grees through 179 degrees, any odd 
flight level, at 2,000-foot intervals be-
ginning at and including flight level 290 
(such as flight level 290, 310, 330, 350, 
370, 390, 410); or 

(ii) On a magnetic course of 180 de-

grees through 359 degrees, any even 
flight level, at 2000-foot intervals be-
ginning at and including flight level 300 
(such as 300, 320, 340, 360, 380, 400). 

[Doc. No. 18334, 54 FR 34294, Aug. 18, 1989, as 
amended by Amdt. 91–276, 68 FR 61321, Oct. 
27, 2003; 68 FR 70133, Dec. 17, 2003; Amdt. 91– 
296, 72 FR 31679, June 7, 2007] 

§ 91.180

Operations within airspace 

designated as Reduced Vertical 
Separation Minimum airspace. 

(a) Except as provided in paragraph 

(b) of this section, no person may oper-
ate a civil aircraft in airspace des-
ignated as Reduced Vertical Separa-
tion Minimum (RVSM) airspace unless: 

(1) The operator and the operator’s 

aircraft comply with the minimum 
standards of appendix G of this part; 
and 

VerDate Sep<11>2014 

16:30 Jun 25, 2019

Jkt 247047

PO 00000

Frm 00751

Fmt 8010

Sfmt 8010

Q:\14\14V2.TXT

PC31

kpayne on VMOFRWIN702 with $$_JOB