"Sabre Two" is a Mercedes-Benz 600 Pullman Limousine. Only about 2700 were built between 1963 and 1981.
The square root of 18 is 4.242640687119285. It might have taken Sabre a second or two to call in those heat-seekers.
In this episode Betty Windom (Cassie Yates) imagines Magnum as this James Bond type of character in her book. In an interview for "Bravo TV's Countdown of the 100 Greatest Television Characters", Tom Selleck said this was initially how writers and producers wanted the Magnum character to be portrayed, which Selleck hated. When asked what he wanted to do, Selleck suggested making Magnum more of a laid back, blue-collar type of guy. His rationale was that if men watched the show and could relate to Magnum, it would bring in even more male viewers. The writers and producers initially refused, and Selleck threatened to do "Raiders of the Lost Ark" (1981) instead. The writers and producers finally relented and Thomas Magnum became the approachable, charming character for which Selleck would become famous.
"Canard a l'orange" is roasted duck served with orange sauce, "Epinard au jus" is spinach braised in stock or cream, and "Gratin Dauphinoise" are scalloped potatoes.
The first of Cassie Yates' two appearances in the series. She would later appear in the Season 6 finale "Photo Play" (1986).