AIM

4/3/14

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

4

−

6

−

9. Contingency Actions: Weather

Encounters and Aircraft System Failures

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

take under certain conditions of aircraft system

failure 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

Initial Pilot Actions in Contingency Situations

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

capability: 

SNotify ATC and request assistance as detailed below. 

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

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

SAlert 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:

SWhen 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)

SIf not issued by the controller, request vector

clear of traffic at adjacent FLs

SIf desired, request FL change or re−route

SReport location and magnitude of turbulence or

MWA to ATC

SVector aircraft to avoid merging target with

traffic at adjacent flight levels, traffic permitting

SAdvise pilot of conflicting traffic

SIssue FL change or re−route, traffic permitting

SIssue 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.”