# Pilot guide: VDGS & CDM

<p id="bkmrk-departing-from-iceland">Departing from <strong>BIKF, BIRK, BIAR, BGGH, BGSF or EKVG</strong>? These airports use CDM (Collaborative Decision Making) to give every flight a fair start-up time and avoid queues at the runway.</p>

<h2 id="bkmrk-the-short-version">The short version</h2>
<ol id="bkmrk-short-version-steps">
<li>File your flight plan with a realistic off-block time (EOBT).</li>
<li>Once on board, go to <a href="https://vats.im/vdgs" target="_blank" rel="noopener"><strong>vats.im/vdgs</strong></a> and confirm or update your <strong>TOBT</strong>: the time you expect to be ready for push and start.</li>
<li>Watch your <strong>TSAT</strong> on the VDGS. This is when you will get start-up.</li>
<li>Call ATC for start-up within <strong>±5 minutes of your TOBT</strong>.</li>
</ol>

<h2 id="bkmrk-the-times">The times</h2>
<table id="bkmrk-times-table" style="border-collapse: collapse; width: 100%;" border="1">
<thead>
<tr><th>Time</th><th>Meaning</th><th>Who sets it</th></tr>
</thead>
<tbody>
<tr><td><strong>EOBT</strong></td><td>Estimated off-block time, from your flight plan</td><td>You, in the flight plan</td></tr>
<tr><td><strong>TOBT</strong></td><td>Target off-block time: when you will be ready to push</td><td>You, on the VDGS (or ATC)</td></tr>
<tr><td><strong>TSAT</strong></td><td>Target start-up approval time: when ATC will approve your start-up</td><td>The CDM system</td></tr>
<tr><td><strong>CTOT</strong></td><td>Calculated take-off time (slot): you must take off within -5/+10 minutes</td><td>Flow management</td></tr>
</tbody>
</table>

<h2 id="bkmrk-good-to-know">Good to know</h2>
<ul id="bkmrk-good-to-know-list">
<li>Your TSAT can change until start-up is approved. Check the VDGS before you call.</li>
<li>Start-up is approved within <strong>±5 minutes of your TSAT</strong>. If you call earlier, you may be asked to wait.</li>
<li>If you are ready earlier than your TOBT, update it on the VDGS. You may get an earlier TSAT.</li>
<li>If you are running late, update your TOBT as soon as you know. This frees your slot for someone else.</li>
<li>If you miss your TOBT by more than 5 minutes, or your TSAT expires, your times are cancelled and you must set a new TOBT.</li>
<li>If you have a <strong>CTOT</strong>, ATC will tell you with your clearance. Read it back and plan to take off on time.</li>
</ul>

<p id="bkmrk-no-vdgs" class="callout info">Confirming your TOBT on the VDGS is not mandatory, but it is the best way to avoid long delays. If you do not, ATC will set your TOBT when you call.</p>