ASPM Weather Factors: Definitions of Variables

The following definitions define the fields in the ASPM reports of Weather Factors:

• % Of Efficiency Counts. The proportion of efficiency operations that experienced each impact level for the selected weather factor.
• % Of Time Periods. The percentage of time periods during which flights experienced each impact level for the selected weather factor.
• % Of Total. Percentage of flights that experienced each impact level for the selected weather factor.
• % On-Time Arrivals Based On Flight Plan. Number of flights that arrive at the gate less than 15 minutes past the flight plan time, expressed as a percent of the total number of Arrivals for Metric Computation.
• % On-Time Arrivals. Percentage of flights that arrived at the gate less than 15 minutes past the scheduled or flight plan time in relation to the total number of Arrivals for Metric Computation.
• % On-Time Departures Based On Flight Plan. Number of flights that depart within 15 minutes of the Flight Plan Wheels Off time. Expressed as a percent of the total number of Departures for Metric Computation.
• % On-Time Departures. Percentage of flights that departed within 15 minutes of the scheduled or flight plan wheels-off time in relation to the total number of Departures for Metric Computation.
• % Scheduled Operations. Percentage of scheduled operations that experienced each impact level (None, Minor, Moderate, Severe, and All) for the selected weather factor.
• ADR + Capacity AAR. The sum of the facility set Airport Departure Rate, and Capacity Airport Arrival Rate during periods that experienced each impact level for the selected weather factor. Also see definition for Wt.
• Airport Weather. Represents the local weather phenomena at this airport. The source is NOAA, acquired daily. A "+" sign means "Heavy" when used in conjunction with a local weather phenomena. See Local Weather Codes for a listing of the local weather phenomena and their factor weights. Also see definition for Wt.
• Average Airborne Delay. The difference between Actual Airborne Time and the flight plan Estimated Time Enroute (Filed ETE), in minutes.
• Average Delay for All Arrivals. The sum of gate arrival delay minutes for delays of one minute or more, divided by the total number of arrivals, for the ASPM 77 airports.
• Average Delay for Delayed Arrivals. The average delay for all flights with an actual Gate In Time delayed 15 minutes or more compared to the schedule or flight plan Gate In Time.
• Average Delay for Delayed Departures. The average delay for flights with a Wheels Off Time delayed 15 minutes or more compared to the schedule or flight plan estimated Wheels Off Time.
• Average Hourly Actuals (Departures, Arrivals, Total). The average hourly count of efficiency operations during periods that experienced each impact level for the selected weather factor.
• Average Taxi-In Delay. The sum of minutes of Taxi In Delay of 1 minute or more, divided by all arrivals. Taxi in Delay equals actual Taxi In Time minus Unimpeded Taxi In Time.
• Average Taxi-Out Delay. The sum of minutes of Taxi Out Delay of 1 minute or more, divided by all departures. Taxi Out Delay equals Actual Taxi Out Time minus Unimpeded Taxi Out time.
• Average Taxi-Out Time. The difference between Actual Gate Out time and Actual Wheels Off time, in minutes, divided by the total number of flights. Taxi out time is observed for flights for which OOOI data are available, otherwise it is estimated. See ASPM: Estimation Techniques.
• Combine Impacts. Filter option to group results by None+Minor and Moderate+Severe impact levels.
• Efficiency Counts (Departures, Arrivals, Total, % Of Total). The count and percentage of efficiency operations that experienced each impact level for the selected weather factor.
• Enroute Thunderstorms. A measure of the incidence of en route thunderstorms encountered by flights of 300 miles or more. For each flight, the presence of thunderstorms enroute are recorded at weather stations within 50 miles of the flight track, at 100 and 200 miles of the departure airport, the mid-point, and 200 and 100 miles of the arrival airport. A score for each hour at the arrival airport is calculated by evaluating the incidence of en route thunderstorms for all arriving flights, with an increasing score based on the number of storms enroute. Hours in which arriving flights frequently encountered more than one thunderstorm en route have a higher severity value than other hours. The final calculation of en route thunderstorms results in a number from 0 (none) to 3 (severe), with 0 indicating that no flights encountered any thunderstorms, and 3 indicating that all arriving flights encountered thunderstorms at 2 or more points along the intended flight path. Enroute Thunderstorms data for any given month are not available until several weeks after the end of the month.
• Hour. Filter option limiting report to a select range of local hours, from 00 to 23.
• Impact. Represents the degree of weather severity. Each hour is given a severity category by weather factor and an overall impacting condition. The categories are None, Minor, Moderate, Severe.
• Local Hour. The hour of the day in local time, ranging from 0–23. Local hour used in efficiency calculations is based on Wheels Off or Wheels On time.
• Metric Arrivals. Flight arrivals used for calculating metrics in ASPM. Includes flight records that meet the following criteria: itinerant flights to or from one of the ASPM 77 Airports or operated by one of the ASPM Carriers with actual arrival and departure and flight plan times that are reported or can be estimated from the other flight record data. General aviation and military flights are excluded. Average Delay for All Departures. The sum of gate departure delay of one minute or more, divided by the total number of departures, for the ASPM 77 airports.
• Metric Departures. Flight departures used for calculating metrics in ASPM. Includes flight records that meet the following criteria: itinerant flights to or from one of the ASPM 77 airports or operated by one of the ASPM Carriers with actual arrival and departure and flight plan times that are reported or can be estimated from the other flight record data. General aviation and military flights are excluded.
• Near By TS. The number of thunderstorms at nearby weather stations such as ASOS and AWOS within 50 miles of this airport at local arrival hour. If a thunderstorm is reported by any nearby station during an hour, the impact is assigned a "severe" value. Also see definition for Wt.
• OPSNET Weather Delays. OPSNET Delay Represents the weather delays from OPSNET distributed hourly. Also see definition for Wt.
• Overall (Impact, Weighted). The impact value represents the extent to which the overall weather affects the airport. Values are None, Minor, Moderate, Severe, and are determined by combining seven factors: Wind Speed, Ceiling, Visibility, OPSNET delays, Airport Weather, Nearby Thunderstorms, and Enroute Thunderstorms. The weighted value represents the Overall accumulation of the weather impact by period. The seven weather factors are multiplied by the corresponding weight "Wt" and the resultant sum is distributed into the categories None, Minor, Moderate, and Severe for each hour according to the group designated in the weather scenario matrix record "Overall". This category represents the overall weather impact by hour by airport for all flights. Also See: Weather Classification Briefing.
• Percentages. Percentage of scheduled operations that experience each impact level for the selected weather factor (in the Percent Report).
• Runways. Filter option limiting report to times when selected runway configurations were in effect.
• Scheduled Arrivals. Number of arrivals listed in a published schedule that experienced each impact level for the selected weather factor.
• Scheduled Departures. Number of departures listed in a published schedule that experienced each impact level for the selected weather factor.
• Scheduled Operations. Number of operations listed in a published schedule that experienced each impact level for the selected weather factor (in the Percent Report).
• System Airport Efficiency Rate (SAER). The SAER during periods that experienced each impact level for the selected weather factor.
• System Perspective (Airport Departure Efficiency rate, Airport Arrival Efficiency Rate, SAER). The airport departure and arrival efficiency rates and SAER during periods that experienced each impact level for the selected weather factor.
• TAER. The Terminal Arrival Efficiency Rate (TAER) during periods that experienced each impact level for the selected weather factor.
• Terminal Arrival Efficiency Rate. The Terminal Arrival Efficiency Rate (TAER) during periods that experienced each impact level for the selected weather factor.
• Time Periods. The number of time periods during which flights experienced each impact level for the selected weather factor.
• Type. Filter option restricting data to reporting based on Schedule or Flight Plan.
• Total Scheduled Operations. The total number of operations listed in a published schedule that experienced each impact level for the selected weather factor (in the Percent Report).
• Val (Value). The value for a particular weather factor measured in appropriate units for the weather phenomenon, e.g. knots for wind speed.
• Visibility (Statute Miles). Represents the meteorological visibility range, expressed in statute miles, ranging from 0 to 99. The source is NOAA. Also see definition for Wt.
• Weather Conditions. Filter option limiting report to weather conditions reported as Instrument Meteorological Conditions (IMC), Visual Meteorological Conditions (VMC), or All.
• Wind Direction. The measurement in degrees of the direction from which the wind is blowing relative to true north. Based on a 2-minute average just prior to observation time. A value of 'VR' or 'VRB' indicates variable wind direction. A value of zero indicates no wind.
• Wind Speed (Knots). Wind speed at the selected airport, expressed in knots. Also see definition for Wt.
• Ceiling N x 100 (Feet). Measurement in 100 ft increments of the lowest level of clouds that is reported as "broken", "overcast", or "obscured", not considered partial or thin. The value is the actual ceiling. Also see definition for Wt.
• Wt=x (Weight). "Wt=x" is the integer weight for this factor at this airport, ranging from 0 to 3 (0: not significant, 1: significant, 2: very significant, 3: extremely significant). The weight is used to generate the weighted distribution of each weather factor for the calculation of the overall impacting condition.
• Weather Factor. Filter option limiting report to a particular weather factor (Enroute Thunderstorms, Thunderstorms Within 50 Miles, Severity of Local Weather Conditions, Number of Hourly OPSNET Weather Delays, Visibility in Statute Miles, Ceiling in Hundreds of Feet, Wind Speed in Knots) or Overall Impacting Conditions.