3. To determine if the aircraft has "Advanced RNAV" capabilities and can be cleared to fly procedures for
which that capability is required.
g. Improperly changing an aircraft equipment suffix and/or adding "NON-RVSM" in the NOTES or
REMARKS section (Field 18) while not removing the "W" from Field 10, will not provide air traffic control with
the proper visual indicator necessary to detect Non-RVSM aircraft. To ensure information processes correctly
for Non-RVSM aircraft, the "W" in Field 10 must be removed. Entry of information in the NOTES or
REMARKS section (Field 18) will not affect the determination of RVSM capability and must not be used to
indicate a flight is Non-RVSM.
4-6-5. Pilot RVSM Operating Practices and Procedures
a. RVSM Mandate. If either the operator is not authorized for RVSM operations or the aircraft is not
RVSM-compliant, the pilot will neither request nor accept a clearance into RVSM airspace unless:
1. The flight is conducted by a non-RVSM DoD, MEDEVAC, certification/development or foreign State
(government) aircraft in accordance with paragraph 4-6-10, Procedures for Accommodation of Non-RVSM
Aircraft.
2. The pilot intends to climb to or descend from FL 430 or above in accordance with paragraph 4-6-11,
Non-RVSM Aircraft Requesting Climb to and Descent from Flight Levels Above RVSM Airspace Without
Intermediate Level Off.
3. An emergency situation exists.
b. Basic RVSM Operating Practices and Procedures. AC 91-85 contains pilot practices and procedures
for RVSM. Operators must incorporate applicable practices and procedures, as supplemented by the applicable
paragraphs of this section, into operator training or pilot knowledge programs and operator documents
containing RVSM operational policies.
c. AC 91-85 contains practices and procedures for flight planning, preflight procedures at the aircraft,
procedures prior to RVSM airspace entry, inflight (en route) procedures, contingency procedures and post flight.
d. The following paragraphs either clarify or supplement AC 91-85 practices and procedures.
4-6-6. Guidance on Severe Turbulence and Mountain Wave Activity (MWA)
a. Introduction/Explanation
1. The information and practices in this paragraph are provided to emphasize to pilots and controllers the
importance of taking appropriate action in RVSM airspace when aircraft experience severe turbulence and/or
MWA that is of sufficient magnitude to significantly affect altitude-keeping.
2. Severe Turbulence. Severe turbulence causes large, abrupt changes in altitude and/or attitude usually
accompanied by large variations in indicated airspeed. Aircraft may be momentarily out of control. Encounters
with severe turbulence must be remedied immediately in any phase of flight. Severe turbulence may be
associated with MWA.
3. Mountain Wave Activity (MWA)
(a) Significant MWA occurs both below and above the floor of RVSM airspace, FL 290. MWA often
occurs in western states in the vicinity of mountain ranges. It may occur when strong winds blow perpendicular
to mountain ranges resulting in up and down or wave motions in the atmosphere. Wave action can produce
altitude excursions and airspeed fluctuations accompanied by only light turbulence. With sufficient amplitude,
however, wave action can induce altitude and airspeed fluctuations accompanied by severe turbulence. MWA
is difficult to forecast and can be highly localized and short lived.
(b) Wave activity is not necessarily limited to the vicinity of mountain ranges. Pilots experiencing wave
activity anywhere that significantly affects altitude-keeping can follow the guidance provided below.

4-6-4

Operational Policy/Procedures for Reduced Vertical Separation Minimum (RVSM) in the
Domestic U.S., Alaska, Offshore Airspace and the San Juan FIR