United 851 from Chicago. It's the last 777-222ER for United, and two orders were cancelled (MSN 29172 and 30227, both intended to be N230UA).
<a href="//commons.wikimedia.org/wiki/User:N509FZ" title="User:N509FZ">N509FZ</a>
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<span class="int-own-work" lang="en">Own work</span>