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AIM

10/12/17

4−6−7

Operational Policy/Procedures for Reduced Vertical Separation Minimum (RVSM) in the

Domestic U.S., Alaska, Offshore Airspace and the San Juan FIR

4−6−9. Contingency Actions: Weather

Encounters and Aircraft System Failures

that Occur After Entry into RVSM Airspace

TBL 4−6−2 provides pilot guidance on actions to

take under certain conditions of aircraft system

failure that occur after entry into RVSM airspace

and weather encounters. It also describes the

expected ATC controller actions in these situations. It

is recognized that the pilot and controller will use

judgment to determine the action most appropriate to

any given situation.

TBL 4−6−2

Contingency Actions:  Weather Encounters and Aircraft System Failures that Occur After Entry into RVSM

Airspace

Initial Pilot Actions in Contingency Situations

Initial pilot actions when unable to maintain flight level (FL) or unsure of aircraft altitude−keeping

capability: 

Notify ATC and request assistance as detailed below. 

Maintain cleared flight level, to the extent possible, while evaluating the situation.

Watch for conflicting traffic both visually and by reference to TCAS, if equipped.

Alert nearby aircraft by illuminating exterior lights (commensurate with aircraft limitations).

Severe Turbulence and/or Mountain Wave Activity (MWA) Induced 

Altitude Deviations of Approximately 200 feet

Pilot will:

Controller will:

When experiencing severe turbulence and/or

MWA induced altitude deviations of

approximately 200 feet or greater, pilot will

contact ATC and state “Unable RVSM Due (state

reason)” (e.g., turbulence, mountain wave)

If not issued by the controller, request vector

clear of traffic at adjacent FLs

If desired, request FL change or re−route

Report location and magnitude of turbulence or

MWA to ATC

Vector aircraft to avoid merging target with

traffic at adjacent flight levels, traffic permitting

Advise pilot of conflicting traffic

Issue FL change or re−route, traffic permitting

Issue PIREP to other aircraft

See Paragraph 4−6−6, Guidance on Severe

Turbulence and Mountain Wave Activity (MWA) for

detailed guidance.

Paragraph 4−6−6 explains “traffic permitting.”