Patrick Smith, an airline pilot who writes for Salon.com gives his assessment of what might have happened and why the accident points to a potentially troubling scenario.

The million-dollar question, obviously, is how in the world did all three landing gear units of a modern commercial airliner fail to come down?

I wish I could tell you. I fly 767s for a living and I’m as mystified as anybody else. The plane has both a normal and alternate gear extension system. The normal system uses hydraulics, the alternate relies mostly on gravity, allowing the huge assemblies to more or less free-fall into place if need be. Neither of these, for reasons we’ll learn soon enough, did the trick. Whatever the problem was, it seems to have been something pretty far up the chain of the systems’ architecture, such that neither of two independent systems was sufficient.

The 767 has been in service for nearly 30 years, together with its little brother, the 757. The 767 is the much larger of the two, but otherwise these aircraft are extremely similar, sharing a so-called common type certification that allows pilots like me to be simultaneously qualified on both. In all the millions of landings these planes have made over the past three decades, nothing like this has happened before.

LOT, for its part, is a small but well-respected carrier with an excellent safety record. A freak malfunction? A maintenance mistake of some kind? We’ll find out eventually.