Most people who regularly read newspapers understand that it’s not journalists, but subeditors, who write the headlines.
Really? Is there a survey of readers which shows this to be the case? Or is this just another assumption on your part?
Whether it's you or subeditors who write the headlines, this particular one is a disgrace. It reflects badly on you and your paper.
I believe your paper should issue an unreserved apology to the grieving families and friends of those who perished in both accidents. It's the right thing to do - and probably wise!
Di