NBC News has effectively owned the network’s Sunday 7 p.m. time period for decades, but what it hasn’t owned is the audience — a loyal (or hidebound) one that would have to be dragged kicking or screaming away from the “60 Minutes” fix that has held it in place for nearly half a century.

But NBC continues to try, and the latest effort — a worthy one — concludes this Sunday. After a brief six-week run, “On Assignment” will at least leave the air with something of a bang: a Tom Brokaw interview of David Letterman, the latter’s first television one since leaving “Late Show” a year ago.

“On Assignment” has eschewed the staple of so much of the rest of TV news lately (Donald Trump), and has instead looked elsewhere. Far elsewhere: Like a recent Harry Smith piece from the Palmyra Atoll a couple of thousand miles south of Hawaii, or Cynthia McFadden’s jail interview in Romania of Marcel Lazar Lehel, the hacker known as Guccifer, who outed George W. Bush’s avocation as a painter and who claimed to have hacked the personal email server that Hillary Clinton used while secretary of state.

But during its brief run, “On Assignment” has also provided a high-end home for some of the network’s best correspondents, including Richard Engel — who most recently reported a story on drone warfare — and Josh Mankiewicz, who got his teeth into a boondoggle in his own home state of California: the Bay Bridge, which cost $6.4 billion, or $5 billion over budget, at a direct cost to taxpayers.

I spoke recently with David Corvo, NBC’s senior executive producer of prime-time news, and Liz Cole, executive producer of “On Assignment”:

 

This six-week run seemed almost like a tryout for something that might become a regularly scheduled series in the future. What’s the plan?

Corvo: I wouldn’t call it a tryout but more of a limited experiment. We’ve experimented in that time period almost every year for 20 years, and like to come up with something different, like last year’s, which set up scenarios with kids and whether they’d ever do that [“My Kid Would Never Do That”] or “Escape,” first-person survivor stories. We also did a lot of hours in that time period about pretty serious topics — wrongful conviction, aging out of autism, medical marijuana — and felt that with some of the stories we stretched them to an hour, while with others we passed on because we felt it couldn’t fill an hour. So we said, let’s go back to the future and try a few weeks where we do multiple stories and let those try to tell us how long they should be.

 

Is this also NBC’s attempt to create its own “60 Minutes,” which would then compete against “60 Minutes”?

Corvo: It’s really just a way of saying, “What else can we do with this real estate that we don’t usually get a chance to do?” The only thing about this time period that we’ve noticed is that it seems to attract those who are willing to pay attention to substantive stories.

 

How did the Brokaw/Letterman interview come together?

Cole: Brokaw has been working on that for a year. It’s a great interview and clearly they are so comfortable together, and you see that Letterman is being totally candid. He’s relaxed, he’s spirited, and he’s just telling it like it is. He doesn’t miss late night at all — spending time with his family and other parts of his life. Tom is funny, too. Letterman tells a story about the early days, and Tom matches him. The rapport between them is a pleasure to watch.