INSTRUMENT PROCEDURES HANDBOOK
 

WEATHER SOURCES

Most of the weather information that flight crews receive is issued to them prior to the start of each flight segment, but the weather used for inflight planning and execution of an instrument approach is normally obtained en route via government sources, company frequency, or Aircraft Communications Addressing and Reporting System (ACARS).

Air carriers and operators certificated under the provisions of Part 119 (Certification: Air Carriers and Commercial Operators) are required to use the aeronautical weather information systems defined in the OpsSpecs issued to that certificate holder by the FAA. These systems may use basic FAA/National Weather Service (NWS) weather services, contractor or operator-proprietary weather services and/or Enhanced Weather Information System (EWINS) when approved in the OpsSpecs. As an integral part of EWINS approval, the procedures for collecting, producing, and disseminating aeronautical weather information, as well as the crewmember and dispatcher training to support the use of system weather products, must be accepted or approved.

Operators not certificated under the provisions of Part 119 are encouraged to use FAA/NWS products through Automated Flight Service Stations (AFSSs), Direct User Access Terminal System (DUATS), and/or Flight Information Services Data Link (FISDL). Refer to the Aeronautical Information Manual (AIM) for more information regarding AFSSs, DUATS, and FISDL. The suite of available aviation weather product types is expanding with the development of new sensor systems, algorithms, and forecast models. The FAA and NWS, supported by the National Center for Atmospheric Research and the Forecast Systems Laboratory, develop and implement new aviation weather product types through a comprehensive process known as the Aviation Weather Technology Transfer process. This process ensures that user needs and technical and operational readiness requirements are met as experimental product types mature to operational application.

The development of enhanced communications capabilities, most notably the Internet, has allowed pilots access to an ever-increasing range of weather service providers and proprietary products. It is not the intent of the FAA to limit operator use of this weather information. However, pilots and operators should be aware that weather services provided by entities other than the FAA, NWS, or their contractors (such as the DUATS and FISDL providers) may not meet FAA/NWS quality control standards. Therefore, operators and pilots contemplating use of such services should consider the following in determining the suitability of that service or product. In many cases, this may be accomplished by provider disclosure or a description of services or products:

Is the service or product applicable for aviation use?

  • Does the weather product or service provide information that is usable in aeronautical decision- making?
  • Does the product or service fail to provide data necessary to make critical aeronautical weather decisions?

Does the service provide data/products produced by approved aviation weather information sources?

Are these data or this product modified?

  • If so, is the modification process described, and is the final product in a configuration that supports aeronautical weather decision-making?

Are the weather products professionally developed and produced and/or quality-controlled by a qualified aviation meteorologist?

Does the providerís quality assurance plan include the capability to monitor generated products and contain a procedure to correct deficiencies as they are discovered?

Is the product output consistent with original data sources?

Are education and training materials sufficient to enable users to use the new product effectively?

Are the following key elements of the product intuitive and easy for the user to interpret?

  • Type of data/product.
  • Currency or age of data/product.


     Figure 5-1. Chippewa Regional Airport (KEAU), Eau Claire, Wisconsin.

  • Method for displaying and decoding the data/product.
  • Location/mapping of the data. Is the product suitable for use? Consider potential pilot misunderstandings due to:
  • Complexity of the product.
  • Nonstandard display (colors, labels).
  • Incorrect mapping/display of data.
  • Incorrect overlay of weather data with other data (terrain, navigational aids (NAVAIDs), waypoints, etc.).
  • Inappropriate display of missing data.
  • Missing or inaccurate time/date stamp on product. Pilots and operators should be cautious when using unfamiliar products, or products not supported by technical specifications that satisfy the considerations noted above.

NOTE: When in doubt, use FAA/NWS products with the consultation of an FAA AFSS specialist.

 

 

 

 
 
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