Assessment of TAF, METAR, and SPECI Reports Based on ICAO ANNEX 3 Regulation

Abstract

The Terminal Aerodrome Forecast (TAF) is one of the most prominent and widely accepted forecasting tools for flight planning. The reliability of this instrument is crucial for its practical applicability, and its quality may further affect the overall air transport safety and economic efficiency. The presented study seeks to objectify the assessment of the success rate of TAFs in the full breadth of their scope, unlike alternative approaches that typically analyze one selected element. It aspires to submit a complex survey on TAF realization in the context of ANNEX 3 (a regulation for Meteorological Service for International Air Navigation issued by the International Civil Aviation Organization (ICAO)) defined methodology and to provoke a discussion on the clarification and completion of ANNEX 3. Moreover, the adherence of TAFs to ICAO ANNEX 3 (20th Edition) is examined and presented on the example of reports issued in the Czech Republic. The study evaluates the accuracy of TAF forecast verified by Aerodrome Routine Meteorological Report (METAR) and Special Meteorological Report (SPECI), whose quality was assessed first. The required accuracy of TAFs was achieved for most evaluated stations. A discrepancy in terms of formal structure between actually issued reports and the ANNEX 3 defined form was revealed in over 90% of reports. The study identifies ambiguities and contradictions contained in ANNEX 3 that lead to loose interpretations of its stipulations and complicate the objectification of TAF evaluation.

Model for Managing Divert Risk Caused by Low Visibility in Airline Operations Management

“…TAF problems have broadly been studied in the literature because they are reflected in airlines as delay and divert costs in addition to safety. Novotny et al ( 27 ) studied the generation and realization ratio of TAFs according to the methodology in ICAO Annex 3 ( 27 ). Similarly, Harris ( 28 ) studied the accuracy of TAFs with different scoring methods for comparison, and Patriarca et al ( 32 ) studied determining TAF accuracy levels in managing airport weather forecasts with anomaly detection and hierarchical clustering because of its importance for decision-makers.…”

“…However, delay and cancellation decisions adversely affect the airline because of additional costs, especially when these forecasts are not realized. Studies on the realization ratio of TAFs show that the ratio may vary according to the airport, revealing that this issue should be considered in airline operation decisions ( 27 , 28 ). For this purpose, instead of delaying or canceling flights per the forecasts in the TAF report, divert risk analysis can be made using past-period data for meteorological conditions, and the most optimum decision relating to the relevant flight can be made ( 7 , 8 ).…”

“…Checking the Relationship Between General Visibility and RVR in the METAR When the TAFs Were Correct. The RVR is the range over which the pilot of an aircraft on the center line of a runway can see the runway surface markings or the lights delineating the runway or identifying its center line (ICAO Annex 6: Operation of Aircraft) (27). The RVR is the horizontal visibility distance from the runway head.…”

The Influence of Visibility on the Opportunity to Perform Flight Operations with Various Categories of the Instrument Landing System

“…Up-to-date meteorological information is essential for the smooth operation of the airport in the event of changing weather conditions. Meteorological information for flight planning is developed in the form of weather forecasts using the global area forecast system [ 48 ]. Various dispatches are developed and transmitted for the flight crews and for airport services.…”

Performance-based Analysis of Aerodrome Weather Forecasts

“…For example, data aggregation techniques to allow shifting from individual TAFs' accuracy to organization-wide dynamic sets of TAFs seems to be a partially open challenge. In this regard, some limitations can be acknowledged: (i) limited periods of analysis (e.g., [9], where authors evaluated forecasting performance based on 24h operations data); (ii) restricted geographical area (e.g., [10], where authors evaluated forecasting performance using data from 5 Czech airports).…”