"I do not believe it!" the woman shrieks at full volume, threatening me with bodily harm if I go anywhere near her children. I empathize: She and her brood are now facing a frisking, a hand wanding, and a search of their belongings, which may be tested for traces of explosives.

Reeled in by the commotion, a fellow screener tries to calm the woman down. "Actually, ma'am, the TSA didn't select you," he says. "The airline selected you."

This is what we've been told to say to fliers who complain about this auto-da-fé; for once, we can honestly deflect the blame away from the TSA. But the excuse is in fact an admission of glaring deficiencies that persist in the way we screen passengers. We are using a minor variation on the same flawed system for identifying suspicious persons that failed on 9/11.

I wasn't taught why certain passengers are chosen for additional screening, but I know from my years covering aviation security as a reporter that some are picked at random and others are selected because of certain red flags. Chances are that whatever computer reviewed this family's data when they checked in saw only a group of five people traveling together on a one-way, last-minute booking. In other words, the M.O. of a terrorist cell on 9/11. I learn the real story when the woman angrily relates that her mother has just died and they are flying to the funeral. They didn't book a return flight because they weren't sure how long they would be staying.

I am struck by the fact that at this major urban airport, five years after the worst terrorist attack on U.S. soil, we are still relying on the same rudimentary tools that have been used for decades to detect who is a true threat: physical pat-downs and basic X-ray technology along with the out-of-date passenger pre-screening that continues to bedevil people such as the woman before me.

Mercifully, a supervisor swoops in and excuses the two youngest members of the group from a full pat-down; the others are checked and found to be weapon-free. They make their flight. A businessman who is about to miss his because of this kerfuffle looks at me and mutters, "When are you guys going to start using your brains?"

Six months earlier, I had spotted a job advertisement online for part-time airport security screeners. The posting was notable for its dry recitation of the drawbacks of the job, as if to discourage all but the most desperate from applying. "This is a very physically demanding job with unique requirements," it read; I'd have to stand for up to four hours without a break, lift seventy-pound bags, and walk the equivalent of two miles during my shift. I would be expected to maintain my cool while dealing with constant stress from the noise, crowds, and "disruptive and angry passengers," which I couldn't let distract me from my ultimate objective: to ferret out what it described as "devices intended on creating massive destruction." For this I'd be paid $13.91 an hour; I'd work weekends, holidays, and odd hours; and I'd remain on probation for two years, during which time I could be fired without warning.