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AIM 

4/20/23 

TBL 4

6

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 

Vector aircraft to avoid merging target with 

MWA induced altitude deviations of 

traffic at adjacent flight levels, traffic permitting 

approximately 200 feet or greater, pilot will 

contact ATC and state “Unable RVSM Due (state 

Advise pilot of conflicting traffic 

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

Issue FL change or re

route, traffic permitting 

If not issued by the controller, request vector 

clear of traffic at adjacent FLs 

Issue PIREP to other aircraft 

If desired, request FL change or re

route 

Report location and magnitude of turbulence or 

MWA to ATC 

See paragraph 4

6

6, Guidance on Severe 

Paragraph 4

6

6 explains “traffic permitting.” 

Turbulence and Mountain Wave Activity (MWA) for 

detailed guidance. 

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 

Report location and magnitude of MWA to ATC 

See paragraph 4

6

6 for guidance on MWA. 

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 

Issue FL change or re

route, traffic permitting 

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. 

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

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

4

6