Overview

This tool analyses the Arrivals board that Bristol Airport publish on their website to estimate the level of conflicting traffic for your arrival.

Conflicting traffic is considered to be traffic that arrives on blocks between zero and ten minutes before you do.

Input

Enter the flight number of your inbound sector(s) in the text box — use a space to separate multiple flight numbers — then click “Analyse”.

If you are running very behind schedule, your new projected arrival time may fall beyond the range of the calculation. In this case, you can move the range forward in time by adding a + and the number of minutes projected delay to the flight number, e.g. ezy1234+90 for a 90 minute projected delay. This procedure will also be necessary to find your flight if you are running the calculation after your scheduled arrival time; the algorithm finds your flight details by finding the first future arrival with the provided flight number.

Output

Each column of the “Probabilities” table gives the probability of a given quantity of aircraft conflicting with your arrival; for example the “≤2” column gives the probability that you will encounter two or less conflicting aircraft.

The rows of the “Probabilities” table are your own predicted delay, i.e. if you were running 10 minutes behind schedule, you would use the “10” row.

The “Arrivals considered” table shows the list of all arrivals that were considered for the calculation. Each row of the table considered a subset of this list.

Limitations

• Delays are assumed to be independent. Events simultaneously causing delays to multiple inbound aircraft render the calculation void.
• No account is taken of what is actually happening on the day: if a flight is cancelled, for example, it will still be considered by the analysis.
• No account is taken of the effect of departures.

Tips

• If running the calculation of your company iPad, you can share the result with the “Books” app by clicking the square icon with the up arrow. This gives you access to the results when not connected to the Internet. The calculation itself must be carried out when online.
• The same menu also has an “Add to Home Screen“ option if you scroll down. This will allow you to drop a shortcut on to the main iPad screen for quick access to the web page.

Methodology

A set of nine time windows, each of length 10 minutes, is created around your scheduled arrival time. This provides analysis for actual arrival times between twenty minutes ahead of schedule to an hour behind schedule.

A cumulative distribution function, derived from an analysis of historic inbound delays, is then applied to each flight listed on the Bristol Airport Arrivals board, in order to determine the probability that the flight will arrive within each 10 minute window. These probabilities are then combined to give the probabilities of encountering less than or equal to a given number of arrivals in each time window.