NW flight 188: the pilots speak
If you're still curious about NW 188, the flight whose pilots "missed" Minneapolis and realized their error halfway across the next state (background here and here), via AVweb here is the NTSB's extensive full docket of info on the case, including interview summaries with the two pilots, the airline's dispatchers, and others.
Chronicles of aviation mishaps can be very gripping, as my former Atlantic colleague William Langewiesche has demonstrated many times. In this case (as with the "miracle on the Hudson, subject of Langewiesche's latest book) the fascination is guilt-free, since there were no fatal consequences. Sample detail from this new info: whatever the root of the problem here, it certainly wasn't lack of experience. The Captain had 20,000 hours of flight time (a lot), and the First Officer began flying at age 14 and had been an F-111 pilot in the Air Force. Reading the comments of these very, very experienced people who realize they have done something .... inexplicable is surprisingly absorbing.*

After the jump: Since a previous colloquy, here and here, about the legal implications of the terms "frolic" and "detour" also arose from NW 188, two final reader dispatches on the legal semantics of the question.
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* Speaking of gripping and inexplicable: this story, by Gene Weingarten in the Washington Post magazine, recounts the horror and living hell of parents who... somehow... forgot that they had left an infant in the back seat of the car on a broiling hot day. I read it when it came out early this year and can't get it out of my mind. By comparison, the NW 188 story is light comedy.
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To review the state of "frolic" studies: In its letter revoking the flight certificates of the NW 188 pilots, the FAA said the crew had been on a "frolic of your own," language I found "colorful." Then some lawyers wrote in to inform me that this was legal boilerplate; then other lawyers wrote in to say that it was incorrect use of boilerplate.
And still the lawyers write in! Two further entries that, IMHO, add interesting twists to the field of frolic-studies. Any further submissions will be for my eyes only. Thanks to all who wrote in.
1) Yes, it was too a lawyer who wrote the "frolic" letter. In response to the claim of defective frolic-terminology, this message from reader JA:
"I'd be very surprised if the FAA's Determination of Emergency was drafted by a non-lawyer and that the author chose to include the phrase "frolic of your own" without knowing of any special meaning.
"The Determination is, of course, a legal document and contains a legal finding, subject to challenge before an Administrative Law Judge and in federal court. That's why it was issued by the FAA's Office of Regional Counsel. Additionally, there's no way the attorney who signed the finding is putting his name on something with legal-sounding phrases thrown around willy-nilly.
"What's more likely is that the frolic line was included to protect Northwest. The Determination alleges conduct which would clearly constitute negligence if any harm had arisen from it. It characterizes the actions as putting people in "serious jeopardy" and as being "extremely reckless." By including the frolic line, the FAA is making sure that their finding can't be used to show liability on Northwest's part or as evidence in a lawsuit against the airline. A more cynical person might think that the FAA's frolic finding, being unnecessary to the Determination, is a attempt to proactively shield Northwest by finding a lack of vicarious liability on the airline's part, without the rigor of the adversarial process."
2) On the ancient history of frolicking:
"Frolic & detour used to be a favorite of law examiners back in the Pleistocene; the standrd learning was that a manager might be liable for the misdeed of his employee unless the EE was was off on an F&D; note that it's conjunctive. So as it was said, if he is staying in the intended hotel room but brings back a girlfriend and accidentally burns the place down in a spasm of whoopee, we may have a finding of frolic but not detour; if he takes the long way round but otherwise behaves, we may find detour but no frolic.
"The language is a paraphrase of a comment by one Baron Parke, a 19th Century British judge with knack for the pithy phrase, always welcomed by a law prof looking for classroom examples. William Gaddis' (perhaps) most successful novel, "A Frolic of His Own," is a riff on the same principle.
"I suspect there is not much left of the principle today except entertainment; the limits have probably been stretched enough that scarcely anything would count as an f&d. See: http://snipurl.com/tp0em [www_bailii_org]"