Landing According to 14 CFR part 91, no pilot may land when the  flight visibility is less than the visibility prescribed in the  standard IAP being used. ATC provides the pilot with the  current visibility reports appropriate to the runway in use.  This may be in the form of prevailing visibility, runway visual  value (RVV), or runway visual range (RVR). However, only  the pilot can determine if the flight visibility meets the landing  requirements indicated on the approach chart. If the flight  visibility meets the minimum prescribed for the approach,  then the approach may be continued to a landing. If the flight  visibility is less than that prescribed for the approach, then  the pilot must execute a missed approach regardless of the  reported visibility. The landing minimums published on IAP charts are based on  full operation of all components and visual aids associated  with the instrument approach chart being used. Higher  minimums are required with inoperative components or  visual aids. For example, if the ALSF-1 approach lighting  system were inoperative, the visibility minimums for an ILS  would need to be increased by one-quarter mile. If more  than one component is inoperative, each minimum is raised  to the highest minimum required by any single component  that is inoperative. ILS glideslope inoperative minimums  are published on instrument approach charts as localizer  minimums. Consult the “Inoperative Components or Visual  Aids Table” (printed on the inside front cover of each  TPP) for a complete description of the effect of inoperative  components on approach minimums. aircraft under IFR or in weather conditions less than VFR  minimums unless he or she has met the requirements of Part  91. Remember, these are minimum requirements. Regulations specify minimum equipment for filing an IFR  flight plan. It is the pilot’s responsibility to determine the  adequacy of the aircraft and navigation/communication  (NAV/COM) equipment for the proposed IFR flight.  Performance limitations, accessories, and general condition  of the equipment are directly related to the weather, route,  altitude, and ground facilities pertinent to the flight, as well  as to the flight deck workload. In addition to the weather conditions that might affect a  VFR flight, an IFR pilot must consider the effects of other  weather phenomena (e.g., thunderstorms, turbulence, icing,  and visibility). Inflight turbulence can range from occasional light bumps to  extreme airspeed and altitude variations that make aircraft  control difficult. To reduce the risk factors associated with  turbulence, pilots must learn methods of avoidance, as well as  piloting techniques for dealing with an inadvertent encounter. Turbulence avoidance begins with a thorough preflight  weather briefing. Many reports and forecasts are available to  assist the pilot in determining areas of potential turbulence.  These include the Severe Weather Warning (WW), SIGMET  (WS), Convective SIGMET (WST), AIRMET (WA), Severe  Weather Outlook (AC), Center Weather Advisory (CWA),  Area Forecast (FA), and Pilot Reports (UA or PIREPs). Since  thunderstorms are always indicative of turbulence, areas  of known and forecast thunderstorm activity is always of  interest to the pilot. In addition, clear air turbulence (CAT)  associated with jet streams, strong winds over rough terrain,  and fast moving cold fronts are good indicators of turbulence. Pilots should be alert while in flight for the signposts of  turbulence. For example, clouds with vertical development  such as cumulus, towering cumulus, and cumulonimbus are  indicators of atmospheric instability and possible turbulence.  Standing lenticular clouds lack vertical development but  indicate strong mountain wave turbulence. While en route,  pilots can monitor hazardous inflight weather advisory  service (HIWAS) broadcast for updated weather advisories,  or contact the nearest FSS or En Route Flight Advisory  Service (EFAS) for the latest turbulence-related PIREPs. The more experience a pilot has in VFR and IFR flight,  the more proficient a pilot becomes. VFR experience can  be gained by flying in terminal areas with high traffic  activity. This type of flying forces the pilot to polish the  skill of dividing his or her attention between aircraft control,  navigation, communications, and other flight deck duties.  IFR experience can be gained through night flying which  also promotes both instrument proficiency and confidence.  The progression from flying at night under clear, moonlit  conditions to flying at night without moonlight, natural  horizon, or familiar landmarks teaches a pilot to trust the  aircraft instruments with minimal dependence upon what  can be seen outside the aircraft. It is a pilot’s decision to  proceed with an IFR flight or to wait for more acceptable  weather conditions. Currency as an instrument pilot is an equally important  consideration. No person may act as pilot in command of an  Airborne Equipment and Ground Facilities Weather Conditions Turbulence Instrument Weather Flying Flying Experience Recency of Experience 10-22