Question: Lexie Grey is a part of the ABC medical drama series that began airing on what date?

Context articles: Jackson Avery
Sadie Harris
Chyler Leigh
Tainted Obligation
Martin Henderson
Mark Sloan (Grey's Anatomy)
Lexie Grey
Flight (Grey's Anatomy)
One Flight Down (Grey's Anatomy)
Grey's Anatomy

Jackson Avery, M.D. is a fictional character from ABC prime time medical drama, "Grey's Anatomy", portrayed by actor Jesse Williams.
 The character was created by series creator and executive producer, Shonda Rhimes.
 He was introduced in season six, episode 5, "Invasion" as a former surgical resident from "Mercy West Medical Center" when it merges with "Seattle Grace Hospital".
 Williams initially appeared as a recurring cast member, and was later promoted to a series regular in season seven.
 The character's focal storyline involved his attempt to fit in at his new work environment, and trying to finding his own successes, instead of riding on the coattails of his famous family name.
 The character has also had significant romances with Lexie Grey and Stephanie Edwards.
 He was married but is now divorced to April Kepner.
 The couple had a child, Samuel Avery, who died soon after birth.
 However, the pair have a daughter, Harriett, who was not named after Catherine much to her dismay.
 She was conceived prior to the divorce.
 Dr. Avery later becomes a member of the board of directors at the newly established, "Grey Sloan Memorial Hospital", and is the current chairman.
Sadie Harris was a recurring fictional character from the American television medical drama "Grey's Anatomy", which airs on the American Broadcasting Company (ABC) in the United States.
 The character was created by series producer Shonda Rhimes and portrayed by actress Melissa George.
 Introduced as a surgical intern who has an old companionship with the series' protagonist Meredith Grey (Ellen Pompeo), she eventually forms a friendship with Lexie Grey (Chyler Leigh), and departs after it is revealed she cheated her way into the surgical program.
Chyler Leigh West (pronounced ; "née" Potts; born April 10, 1982), known professionally as Chyler Leigh, is an American actress, singer and model, best known for her portrayals of Janey Briggs in "Not Another Teen Movie" and Dr. Alexandra "Lexie" Grey in the ABC medical drama "Grey's Anatomy".
 In October 2015, she began starring, in a lead role, in the CBS/CW show "Supergirl" as Alexandra "Alex" Danvers.
"Tainted Obligation" is the fourth episode of the sixth season of the American television medical drama "Grey's Anatomy", and the show's 106th episode overall.
 It was written by Jenna Bans and directed by Tom Verica.
 The episode was originally broadcast on the American Broadcasting Company (ABC) in the United States on October 8, 2009.
 In the episode, Dr. Meredith Grey (Ellen Pompeo) and Dr. Lexie Grey (Chyler Leigh)'s father is admitted into the hospital, seeking a liver transplantation.
 Further storylines include Dr. Cristina Yang (Sandra Oh) getting nervous about losing her job, and Dr. Owen Hunt (Kevin McKidd) attempting to perform surgery on a terminal patient with Dr. Izzie Stevens (Katherine Heigl).
Martin Henderson (born 8 October 1974) is a New Zealand actor, known to American audiences for his starring role in the ABC medical drama "Off the Map," for starring in the ABC medical drama "Grey's Anatomy" as Dr. Nathan Riggs, and for his performance as Noah Clay in the critically lauded 2002 horror film "The Ring", while remaining known in his home country for his teenage role as Stuart Neilson in the soap opera "Shortland Street".
Mark Everett Sloan, M.D., F.A.C.S. is a fictional surgeon from the ABC medical drama television series "Grey's Anatomy", portrayed by Eric Dane.
 Dr. Sloan is an attending specializing in plastic surgery.
 Dr. Sloan earned the nickname “McSteamy” for his good looks by the female interns of Seattle Grace later Seattle Grace Mercy West Hospital.
 He was good friends with Dr. Derek Shepherd, a fellow physician at Seattle Grace, but was the catalyst for the end of Shepherd's marriage when Shepherd caught Sloan sleeping with his wife, Addison.
 Later, he pursues a 'forbidden' relationship with Dr. Lexie Grey, straining his relationship with Derek yet again.
 He reveals that he loves Lexie in episodes "Migration", "Flight", "Going, Going, Gone", and "Remember The Time" In the show's ninth season, he dies of injuries sustained in a jet plane crash that also injured or killed several of his colleagues from the hospital.
Alexandra Caroline "Lexie" Grey, M.D. is a fictional character from the medical drama television series "Grey's Anatomy", which airs on ABC in the United States.
 The character was created by series' producer Shonda Rhimes and was portrayed by actress Chyler Leigh from the third through eighth seasons.
 She was introduced as a surgical intern in season three.
 Serving as Meredith Grey (Ellen Pompeo)'s half sister, she transferred to the fictional Seattle Grace Hospital, after her mother's sudden death.
 Eventually named a surgical resident, the character was originally contracted to appear for a multi-episode story arc, but received star billing in the fourth season.
"Flight" is the twenty-fourth and final episode of the eighth season of the American television medical drama "Grey's Anatomy", and the show's 172nd episode overall.
 It was written by series creator Shonda Rhimes, and directed by Rob Corn.
 The episode was originally broadcast on the American Broadcasting Company (ABC) in the United States on May 17, 2012.
 In the episode, six doctors from Seattle Grace Mercy West Hospital who are victims of an aviation accident fight to stay alive, but Dr. Lexie Grey (Chyler Leigh) ultimately dies.
 Other storylines occur in Seattle where Dr. Richard Webber (James Pickens, Jr.) plans his annual dinner for the departing residents, Dr. Owen Hunt (Kevin McKidd) fires Dr. Teddy Altman (Kim Raver), and Dr. Miranda Bailey (Chandra Wilson) gets engaged.
"One Flight Down" is the twentieth episode of the eleventh season of the American television medical drama "Grey's Anatomy", and is the 240th episode overall.
 It aired on April 16, 2015 on ABC in the United States.
 The episode was written Austin Guzman and directed by David Greenspan.
 The episode features a plane crash in Seattle bringing patients to Grey Sloan Memorial and old memories of the season 8's tragic plane crash that claimed the lives of Mark Sloan (Eric Dane) and Lexie Grey (Chyler Leigh) back to Meredith Grey, Arizona Robbins and Owen Hunt.
Grey's Anatomy is an American medical drama television series that premiered on American Broadcasting Company (ABC) as a mid-season replacement on March 27, 2005.
 The series focuses on the fictional lives of surgical interns, residents, and attending physicians, as they evolve into seasoned doctors while trying to maintain personal lives and relationships.
 The title is a play on "Gray's Anatomy", a human anatomy textbook by Henry Gray.