Story highlights Les Abend: United isn't entirely to blame over David Dao's controversial removal from flight

Chicago airport security decided to use force to remove a resisting passenger, he says

Les Abend is a Boeing 777 captain for a major airline with 33 years of flying experience. He is a CNN aviation analyst and senior contributor to Flying magazine. The opinions expressed in this commentary are solely those of the author.

(CNN) Like many, I stood in shock as I watched the cell phone video of Dr. David Dao being forcibly removed from United Express Flight 3411 at Chicago's O'Hare International Airport -- and all because there were no open seats. And when United Airlines CEO Oscar Munoz announced Wednesday that no one has been fired over the incident, I was certain there had to be more to the story.

While I've remained silent until now, as a pilot I feel compelled to offer my two cents. I should note I work for a competing airline, so I'm not going to comment on how United handled the matter, but rather discuss the role of airport security and how crew and gate agents respond to situations such as this one.

Les Abend

I should also emphasize that the nationwide attention to this incident -- which perhaps could have been handled differently by all involved -- came because of the actions of Chicago airport security, which determined physical force was a necessary means to an end. They, not the pilot or the crew, dragged Dao off the plane against his will.

Chicago Department of Aviation spokeswoman Karen Pride said that "the incident on United flight 3411 was not in accordance with our standard operating procedure," and that the officer involved has since been placed on leave pending further review.

For those of us at the pointy end of the airplane, there is no more important task than to ensure the safety of our passengers. But gate agents are responsible for ensuring the proper boarding of passengers. Good flight crews will coordinate with agents, especially in abnormal circumstances, such as inclement weather. As a pilot, I don't usually get involved with the boarding process, except to offer a welcome aboard greeting.

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