Television's tradition of producing pilots for series goes back to the days of radio. A pilot is essentially a dry run for a television show--an episode length film meant to represent what a typical episode of a TV series would be like. It is through television pilots that networks can then decide whether to pick up a series or not. Essentially being test runs for television shows, pilots are not necessary meant to be broadcast. The original pilot for Gilligan's Island was never aired, although footage from it was used in a later episode that involved flashbacks to how the Castaways got on the island. When pilots are broadcast, they are not necessarily the first episode of a series. The second pilot produced for Star Trek, "Where No Man Has Gone Before," was aired as that series' third episode. The pilot for Law and Order, "Everybody's Favourite Bagman," was aired as the sixth episode of that show.
Pilots can often be expensive to produce. And if the prospective television series for which the pilot was made is not picked up, the costs for that pilot can never be recouped. It is the sheer expense of producing pilots that led to the development of what is known as the backdoor pilot. The Slanguage Dictionary of Variety defines a backdoor pilot as "...pilot episode filmed as a standalone movie, so it can be broadcast if it is not picked up as a series..." Here it must be pointed out that this definition is not entirely accurate. While many backdoor pilots are filmed as television movies, there have been many that have also been filmed as episodes of pre-existing television shows. In fact, the use of episodes of TV series already on the air as backdoor pilots for prospective shows may well have occurred much more often in the history of television than the use of television movies as backdoor pilots.
The production of backdoor pilots as television movies may have happened most often during the Seventies. An early example of a television movie that also served as a backdoor pilot was the telefilm Then Came Bronson. Airing on March 24, 1969, Then Came Bronson was the pilot for the series of the same name, which debuted on NBC on September 17, 1969. ABC aired several television movies as backdoor pilots on their ABC Movie of the Week, the title given to the time slot reserved for made for TV movies. The pilots for such ABC series as Alias Smith and Jones, Longstreet, Kung Fu, The Six Million Dollar Man, and Wonder Woman all aired under the heading of ABC Movie of the Week.
Indeed, in the Seventies it seemed as if the entirety of Gene Roddenberry's work in television was in the form of TV movies that also served as backdoor pilots. In fact, Roddenberry's prospective series Genesis II would have no less than two backdoor pilots. The first, entitled Genesis II, aired on March 23, 1973 on CBS. CBS ultimately did not pick up Genesis II, preferring to pick up the series Planet of the Apes, spun off from the popular movie series. Gene Roddenberry would then produce another pilot for Genesis II, which would air under the title Planet Earth on April 23, 1974 on ABC. ABC did not pick up the series either. Another prospective series created by Gene Roddenberry whose pilot aired as a television movie was The Questor Tapes. The television movie/backdoor pilot The Questor Tapes aired on NBC on January 23, 1974. NBC actually gave the series the go ahead, but the show never came to fruition due to conflicts between Gene Roddenberry and both Universal and NBC. Another backdoor pilot for a prospective series by Gene Roddenberry was Spectre, which aired on May 21, 1977 on NBC. NBC did not pick up Spectre as a series.
Several of the most famous shows of the Seventies had pilots which also aired as TV movies, in addition to the shows whose pilots aired on ABC Movie of the Week listed above. The pilot for The Rockford Files aired as a telefilm on NBC on March 27, 1974. The pilot for Little House on the Prairie also aired as a made for TV movie on NBC on March 30, 1970. The pilot for The Incredible Hulk aired as a television movie on CBS on November 4, 1977. Although it would beocme much less common, the practice of creating backdoor pilots through TV movies would continue nto the Eighties. The pilot for Airwolf aired as a two hour movie on CBS on January 22, 1984. While the practice of using TV movies as backdoor pilots would pretty much die out as the Eighties progressed, it still occurs from time time to this day. The pilot for the reinvisioning of the series Battlestar Galactica would air as a two part TV movie on the Sci-Fi Channel in December 2003 and on NBC as well.
Of course, while the use of television movies as backdoor pilots has not been extremely common since the Eighties, the practice of using episodes of TV shows already on the air is still rather commonplace. Indeed, it is a practice that was established relatively early in the history of television. In the Fifties, when a backdoor pilot was aired, it was usually as an episode of an anthology series. Perhaps the most famous example of this is the legendary series The Twilight Zone. The script for the original pilot for The Twlight Zone, "The Time Element," was turned down by CBS in 1957, who showed little interest in the prospective series. It was only after Bert Garnet, then producer of The Westinghouse Desilu Playhouse discovered the script in the vaults of CBS that "The Time Element" would see the light of day as an episode of The Westinghouse Desilu Playhouse. The episode proved so popular with viewers that it would lead to a second pilot for the series, "Where is Everybody," which would air as the first episode of The Twilight Zone.
In the Fifties it was not unusual that The Twilight Zone would get a lease on life as an episode of another anthology series already on the air. Indeed, Four Star Productions (founded by Charles Boyer, Ida Lupino, David Niven, and Dick Powell) would turn the use of backdoor pilots as episodes of their anthology series into an art form. In fact, many of Four Star Productions' Westerns originated as episodes of Dick Powell's Zane Grey Theatre. No less than six episodes of the Western anthology series would give birth to TV shows. The pilot for The Rifleman aired as the episode "The Sharpshooter." The pilot for Trackdown aired as the episode "Badge of Honour." The pilot for Johnny Ringo aired as the episode "Man Alone." Dick Powell's Zane Grey Theatre was not the only Four Star Productions anthology series to feature backdoor pilots. The pilot for the detective series Richard Shayne aired as an episode of the anthology series Decision. Of course, not every show produced by Four Star Productions that featured an episode which was a backdoor pilot was necessarily an anthology series. An episode of Trackdown, on which Robert Culp played Texas Ranger Toby Gilman, served as a backdoor pilot for the series Wanted: Dead or Alive starring Steve McQueen as bounty hunter Josh Randall.
Of course, Four Star Productions did not have a monopoly on using episodes of anthology series as backdoor pilots. The 1960-1961 sitcom Ichabod and Me originated as an episode of Robert Montgomery Presents aired during the 1956-1957 season ("Goodbye, Grey Flannel"). A full fledged, backdoor pilot, "Adams Apples," aired as an episode of another anthology series, G.E. True Theatre in 1960. The pilot for the series Run for Your Life aired as an episode of Kraft Suspense Theatre, "Rapture at Two-Forty," on April 15, 1965. In the Seventies episodes of the series Police Story would serve as backdoor pilots for Police Woman, Joe Forrester, and Man Undercover.
In the late Fifties anthology series would be supplanted by shows with continuing characters, until they would become rare in the Sixties and nearly extinct since that time. This would not prevent producers from using episodes of shows already on the air as backdoor pilots for prospective series. Indeed, as pointed out above, an episode of Trackdown served as the pilot for Wanted: Dead or Alive. This was hardly an isolated case in the Fifties, as there are several other instances in which episodes of pre-existing shows would be used as backdoor pilots for prospective shows. Perhaps the most famous example of a show whose pilot was also the episode of another show is The Andy Griffith Show. Its pilot was the episode "Danny meets Andy Griffith' on the series Make Room For Daddy, which aired in February 1960. In the episode Danny Williams (Danny Thomas) would be arrested for speeding in Mayberry by Sheriff Andy Taylor (Andy Griffith). Of course, an episode of The Andy Griffith Show would in turn serve as a backdoor pilot for Gomer Pyle, U.S.M.C.
The use of episodes of show already on the air as backdoor pilots for prospective series has more or less continued unabated since the late Fifties. In the Sixties an episode of The Man From U.N.C.L.E. ("The Moonglow Affair") would serve as a backdoor pilot for The Girl From U.N.C.L.E. In the Seventies the pilot for Maude was also an episode of All in the Family. An episode of Happy Days would serve as a backdoor pilot for Laverne and Shirley. In the Eighties the pilot for A Different World was also an episode of The Cosby Show.
Using episodes of pre-existing shows as backdoor pilots is still relatively common today. In fact, the pilot for the most popular, hour long drama currently on broadcast network television, NCIS, was a two part episode of JAG ("Ice Queen" and "Meltdown"). In turn, the two part episode entitled "Legend" would serve as the backdoor pilot for the NCIS spin off NCIS: LA. An episode of CSI: Crime Scene Investigation would serve as the pilot for CSI: Miami, and an episode of CSI: Miami would serve as the pilot for CSI: New York.
Most viewers watching an episode of a show which is also a backdoor pilot can generally tell that it is a pilot for a new series. After all, such backdoor pilots are fairly obvious in that the episodes generally centre on a whole new set of characters rather than the regulars. This has led the web site TV Tropes & Idioms to term such pilot episodes as "Poorly Disguised Pilots." The experience of watching episodes of shows which were also backdoor pilots for other, prospective shows in reruns can be particularly strange when the prospective show was never picked up. The final two episodes of Green Acres would also be backdoor pilots for series that did not sell--the first centred on a hotel in Hawaii and the second on the ex-secretary of Oliver Douglas (Eddie Albert) and her new boss. The episode of The Brady Bunch, "Kelly's Kid's," which centred on an interracial family, was another backdoor pilot for a series which did not sell. The concept would later be reworked by Sherwood Schwartz as the short lived 1986 series Together We Stand.
Whether as a stand alone, made for television movie or an episode of a pre-existing show, backdoor pilots do have advantages over traditional pilots, not necessarily made for broadcast. Foremost among these is the fact that in airing the backdoor pilot, it can then recoup its costs. This is particularly true since the advent of DVDs, through which backdoor pilots of shows that did not even sell can make back some of their expenses. Another advantage of backdoor pilots is that can not only serve as a test run of a prospective series for network executives, but for viewers as well. By airing a backdoor pilot, network executives can then observe audience reactions to the pilot, decide if they want to pick up the prospective series, and even fine tune the prospective series to better suit viewers. Although most pilots are not backdoor pilots, it is perhaps because of these advantages that they have remained common throughout the history of American television.