The hijacking of a Boeing 727 aircraft in 1971 is considered one of the most spectacular crimes in the history of the USA. After the hijacker had left the plane with a parachute, he was never seen again. According to a recent newspaper article, a deciphered cryptogram might now solve this mysterious case.

On November 24, 1971, a man who called himself Dan Cooper approached a flight counter at the airport of Portland, Oregon. He booked a flight to Seattle and boarded the aircraft, a Boeing 727-100. Shortly after takeoff, Cooper handed a note to a flight attendant. After she didn’t react immediately, he said: “Miss, you’d better look at that note. I have a bomb.”


The Cooper case

After the flight attendant had read the note, Cooper directed her to sit beside him and showed her the alleged bomb in his briefcase. Cooper then stated his demands: $200,000, four parachutes, and a fuel truck standing by at the destination airport to refuel the aircraft upon arrival. The flight attendant conveyed Cooper’s instructions to the pilots.

The pilots informed air traffic control about the hijacking. The airline’s president authorized payment of the ransom and ordered the crew to cooperate fully with the hijacker.


Cooper was later described as a calm, polite, and well-spoken person.

After the aircraft had landed at Seattle airport, the airline’s local operations manager delivered a cash-filled bag and the parachutes to the pilot. Once the delivery was completed, Cooper ordered all passengers and parts of the crew to leave the plane.

Cooper now instructed the remaining crew to take off again and take a southeast course toward Mexico City at the minimum airspeed possible. The plane’s rear exit door was to be left open. After takeoff, Cooper told the only remaining flight attendant to join the rest of the crew in the cockpit.

While Cooper was alone in the passenger cabin, he parachuted out of the open rear exit door.

47 years later, the Cooper hijacking case is still unsolved. The FBI checked over a thousand suspects, but to no avail. Many theories have been dicussed about Cooper’s identity and whereabouts, but nothing has been prooved. There are numerous websites, press articles, and TV documentaries about this meanwhile legendary crime.

Many aviation experts doubt that Cooper survived his parachute jump. The weather was cold, he didn’t wear appropriate clothing, and his landing place was in mountainous terrain.


Has a hidden message solved the case?

Until recently, no relashionship between the Cooper case and cryptography was known to me. Nevertheless, Cooper was mentioned on this blog once. Last year on April 1st, I used a (modified) version of the Cooper composite sketch to illustrate an article about an alleged murder case that involved an unsolved cryptogram consisting of only one letter. Of course, this story was an April fool’s prank. Reader Kriston apparently recognized the picture and commented: “Mr Cooper again.”

Yesterday, Zodiac Killer expert and reader of this blog, Dave Oranchak, informed me about an article in the New York Daily News. According to this article, a codebreaker named Rick Sherwood (a man I have never heard of before) deciphered a letter sent by Cooper to an Oregon newspaper in 1972. The cleartext allegedly contains a confession and reveals the true identity of Dan Cooper.

If Sherwood’s decipherment is correct, the cleartext states that Cooper’s real name is Robert Rackstraw. Rackstraw, a 74-year old army veteran now living in the San Diego area, has been suspected to be Dan Cooper before (like many others). However, the flight attendants of the hijacked aircraft did not see much similarity between Rackstraw and the offender.

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Kommentare (7)

  1. #1 Klaus Schmeh
    30. Juni 2018

    Karin Isberg via Facebook:
    Very interesting story.

  2. #2 David Oranchak
    30. Juni 2018

    One of several red flags to me:

    “He decoded ;’through good ole Unk’ to mean ‘by skyjacking a jet plane,’ using a system of letters and numbers.”

    Seems likely they forced words to come out using some sort of coincidence generator. Naturally, they won’t show their work, otherwise it would get shot down.

  3. #3 Richard SantaColoma
    30. Juni 2018

    From this quote on Wikipedia, “In January 2018, a small cold case documentary team reported that they had obtained a letter originally written in December 1971 and sent to The New York Times, the Los Angeles Times, The Seattle Times and The Washington Post, with numerous numbers and letters written on it. The team, led by Tom and Dawna Colbert, says that the codes were deciphered and matched to three units Rackstraw was a part of while in the Army…”

    … it sounds as though it is ANOTHER letter, a 1971 letter, with the “numbers and letters written on it”. The letter referred to in the article is from 1972. It would be interesting to see that other letter… is it in print?

  4. #4 Klaus Schmeh
    30. Juni 2018

    @Rich: I haven’t seen this letter yet. Perhaps, it is shown in the TV documentary.

  5. #5 Thomas
    30. Juni 2018

    The other letter(s) from 1971 are shown in the press releases: (apparenty the most detailed coverage of the case!)
    The first five letters contain letter and number sequences that represent the Army units in which Rackstraw served during the ear in Vietnam.
    In the release concerning the 6th letter to the Oregon newspaper from 1972, which apparently contains a cipher/code without numbers, it says: “‘Nam superior uses 1950 Army booklet to unmask a 6th note from jumper”. This refers to Rick Sherwood who served in the same unit. There is an Army technical manual on cryptography from 1950,, up to now I can’t see if it provides a method used in the letter.

  6. #6 Thomas
    30. Juni 2018

    Rackstraw’s Vietnam commander, retired LTC Ken Overturf (4/25/18): “With the ‘Basic Cryptography’ Army manual now in my possession, we have doctrinal validation of the process that (code-cracker) Rick Sherwood used to decipher all of these messages. In addition, DoD records show Rackstraw learned this coding process at Fort Bragg, North Carolina, in a Special Warfare Operations Course in 1968.”

  7. #7 Thomas
    1. Juli 2018

    ‘Basic Cryptography’ from 1950 seems to contain only conventional transposition and substitution ciphers that yield ciphertexts which are gibberish and as long as the plaintexts. Both is not the case in “through good ole Unk” and “please tell the lackey cops”. What do you think?