Mountain Wave Activity (MWA) Encounters - General
Pilot actions:
Contact ATC and report experiencing MWA
If so desired, pilot may request a FL change or
re-route

Controller actions:
Advise pilot of conflicting traffic at adjacent FL
If pilot requests, vector aircraft to avoid merging
target with traffic at adjacent RVSM flight levels,
traffic permitting

Report location and magnitude of MWA to ATC
Issue FL change or re-route, traffic permitting

See paragraph 4-6-6 for guidance on MWA.

Issue PIREP to other aircraft
Paragraph 4-6-6 explains "traffic permitting."

NOTE-
MWA encounters do not necessarily result in altitude deviations on the order of 200 feet. The guidance below is
intended to address less significant MWA encounters.

Wake Turbulence Encounters
Pilot should:
Contact ATC and request vector, FL change or,
if capable, a lateral offset
See Paragraph 4-6-7, Guidance on Wake
Turbulence.

Controller should:
Issue vector, FL change or lateral offset
clearance, traffic permitting
Paragraph 4-6-6 explains "traffic permitting."

"Unable RVSM Due Equipment"
Failure of Automatic Altitude Control System, Altitude Alerter or All Primary Altimeters
Pilot will:
Contact ATC and state "Unable RVSM Due
Equipment"
Request clearance out of RVSM airspace unless
operational situation dictates otherwise

Controller will:
Provide 2,000 feet vertical separation or
appropriate horizontal separation
Clear aircraft out of RVSM airspace unless
operational situation dictates otherwise

One Primary Altimeter Remains Operational
Pilot will:
Cross check stand-by altimeter

Controller will:
Acknowledge operation with single primary
altimeter

Notify ATC of operation with single primary
altimeter
If unable to confirm primary altimeter accuracy,
follow actions for failure of all primary altimeters

4-6-8

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