Editing D. B. Cooper (section)

=== Knowledge and planning ===
Based on the evidence and Cooper's tactics, the FBI speculated Cooper planned the hijacking carefully using detailed, specific knowledge of aviation, the local terrain, and the 727's capabilities. Cooper chose a seat in the last row of the rear cabin for three reasons: to observe and respond to any action in front of him, to minimize the possibility of being approached or attacked by someone behind him, and to make himself less conspicuous to the rest of the passengers.{{sfn|Edwards|2021|pp=13}} To ensure he would not be deliberately supplied with sabotaged equipment, Cooper demanded four parachutes to force the assumption he might compel one or more hostages to jump with him.<ref>{{cite web |last=Cheung |first=Kylie |date=June 10, 2021 |title=The ongoing mystique of D.B.&nbsp;Cooper, from documentaries to the Marvel Cinematic Universe |url=https://www.salon.com/2021/06/10/db-cooper-loki/ |url-status=live |archive-url=https://web.archive.org/web/20220114004957/https://www.salon.com/2021/06/10/db-cooper-loki/ |archive-date=January 14, 2022 |access-date=January 14, 2022 |website=Salon |language=en}}</ref> FBI agent Ralph Himmelsbach noted Cooper's choice of a bomb—instead of other weapons previously used by hijackers—thwarted any multidirectional attempts to rush him.{{sfn|Himmelsbach|Worcester|1986|p=52}}

Cooper was careful to avoid leaving evidence. Before he jumped, Cooper demanded Mucklow return to him all notes either written by him, or on his behalf. Mucklow said she used the last match in his paper matchbook to light one of his cigarettes, and when she attempted to dispose of the empty matchbook, he demanded she return it to him.{{r|vault_64|page=154}} Although Cooper meticulously attempted to retrieve evidence, he left his clip-on tie in his seat.{{r|vault_64|page=292|quote="On the seat numbered 18E a black clip-on tie was observed."}}

Cooper was clearly familiar with the 727's capabilities and confidential features, but the 727's design was the primary reason Cooper chose the aircraft. With its aft airstair and the placement of its three engines, the 727 was one of the only passenger jets from which a parachute jump could be easily made. Mucklow told the FBI Cooper appeared to be familiar with the 727's typical refueling time and procedures.{{r|vault_64|page=154|quote='The hijacker displayed an extensive knowledge of the aircraft and specifically well informed in refueling procedures'}}<ref>{{cite news |title=50&nbsp;years on, the unsolved D.B.&nbsp;Cooper skyjacking is the stuff of legends |website=Portland Monthly |url=https://www.pdxmonthly.com/news-and-city-life/2021/11/mystery-db-cooper-skyjacking |url-status=live |access-date=January 14, 2022 |archive-url=https://web.archive.org/web/20220114005002/https://www.pdxmonthly.com/news-and-city-life/2021/11/mystery-db-cooper-skyjacking |archive-date=January 14, 2022 |language=en-US}}</ref>

By specifying a 15° flap setting, Cooper displayed specific knowledge of aviation tactics and the 727's capabilities. Unlike most commercial jet airliners, the 727 could remain in slow, low-altitude flight without stalling. The flap setting Cooper specifically requested allowed him to control the 727's airspeed and altitude without entering the cockpit, where he could have been overpowered by the three pilots.<ref>{{cite book |author=DK |url=https://books.google.com/books?id=89epDgAAQBAJ |title=The Crime Book: Big ideas simply explained |date=February 2, 2021 |publisher=Penguin |isbn=978-1-4654-6667-9 |pages=41 |language=en |access-date=January 14, 2022 |archive-url=https://web.archive.org/web/20240727133336/https://books.google.com/books?id=89epDgAAQBAJ |archive-date=July 27, 2024 |url-status=live}}</ref> First Officer Bill Rataczak, who spoke with Cooper on the intercom during the hijacking, told the FBI, "[Cooper] displayed a specific knowledge of flying and aircraft in general."{{r|vault_64|page=321|quote='...&nbsp;the hijacker displayed a specific knowledge of flying and aircraft in general.'}}

The most significant knowledge Cooper displayed was a feature both secret and unique to the 727: the aft airstair could be operated during flight, and the single activation switch in the rear of the cabin could not be overridden from the cockpit.<ref name=":4">{{cite web |last=Wood |first=Richard |date=November 24, 2019 |title=DB Cooper mystery: The most intriguing hijacking case in history |url=https://www.9news.com.au/world/aviation-news-how-db-cooper-hijacking-changed-air-travel/fada300a-e8e5-4991-b41d-6f0a3653a63d |url-status=live |archive-url=https://web.archive.org/web/20220114004953/https://www.9news.com.au/world/aviation-news-how-db-cooper-hijacking-changed-air-travel/fada300a-e8e5-4991-b41d-6f0a3653a63d |archive-date=January 14, 2022 |access-date=January 14, 2022 |website=[[Nine News]]}}</ref> Cooper knew how to operate the aft staircase, and had clearly planned to use it for his escape. The FBI speculated Cooper knew the [[Central Intelligence Agency]] was using 727s to drop agents and supplies into enemy territory during the Vietnam War.{{sfn|Himmelsbach|Worcester|1986|p=43}} Since no situation on a passenger flight would necessitate such an operation, civilian crews were neither informed the aft airstair could be lowered midflight, nor were they aware its operation could not be overridden from the cockpit.<ref>{{harvnb|Himmelsbach|Worcester|1986|p=43}}: "That the Boeing 727 could be flown with the after stair down was not known to the crew".</ref>

Cooper appeared to be familiar with parachutes, although his experience level is unknown. Mucklow said Cooper, "appeared to be completely familiar with the parachutes which had been furnished to him",{{r|vault_64|page=156 |quote='She also commented that he appeared to be completely familiar with the parachutes which had been furnished to him.'}} and told a journalist, "Cooper put on [his] parachute as though he did so every day".<ref>{{harvnb|Colbert|Szollosi|2016|p=73}}: "Tina said he put the chute on as if he'd done it every day."</ref> Cooper's familiarity with the military-style parachutes he was given has resulted in speculation that Cooper was a military parachutist and not a civilian skydiver.{{sfn|Edwards|2021|pp=27}}

Larry Carr, who directed the investigative team from 2006 to 2009, does not believe Cooper was a [[paratrooper]].<ref>{{cite news |title=FBI No Longer Looking for DB Cooper |url=https://www.seattletimes.com/seattle-news/law-justice/case-closed-fbi-no-longer-looking-for-db-cooper/ |access-date=13 October 2022 |agency=The Seattle Times |date=July 12, 2016 |archive-date=October 13, 2022 |archive-url=https://web.archive.org/web/20221013214529/https://www.seattletimes.com/seattle-news/law-justice/case-closed-fbi-no-longer-looking-for-db-cooper/ |url-status=live }}</ref> Instead, Carr speculates Cooper had been an Air Force aircraft cargo loader. An aircraft cargo-loading assignment would provide him with aviation knowledge and experience: cargo loaders have basic jump training, wear emergency parachutes, and know how to dispatch items from planes in flight. As a cargo loader, Cooper would be familiar with parachutes, "but not necessarily sufficient knowledge to survive the jump he made".<ref name="autogenerated1">{{cite report |url=https://archives.fbi.gov/archives/news/stories/2009/march/in-search-of-d.b.-cooper/dbcooper_031709 |title=In Search of D.B.&nbsp;Cooper: New developments in the unsolved case |date=March 17, 2009 |publisher=[[Federal Bureau of Investigation]] |access-date=November 9, 2016 |archive-url=https://web.archive.org/web/20161109220916/https://archives.fbi.gov/archives/news/stories/2009/march/in-search-of-d.b.-cooper/dbcooper_031709 |archive-date=November 9, 2016 |website=FBI.gov}}</ref>