Seattle NORJAK report: pressure-bump test flight and determination of jump point
Document date 30 May 1973
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Id: Cooper-Part-60:310-311
Subject: Cooper Files: Cooper-Part-60:310-311 Document: Seattle NORJAK report: pressure-bump test flight and determination of jump point Id: Cooper-Part-60:310-311 Page: https://cooper.theunsolved.net/documents/Cooper-Part-60%3A310-311 What is wrong (title, date, type, which pages belong together, copies)? What does the scan show?
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FBI 164-81, Vault Part 60 pp. 310–311 (DB Cooper-24995–24996), Report, dated 30 May 1973 — cooper.theunsolved.net/documents/Cooper-Part-60%3A310-311
SE 164-81
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b6 b7C
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Northwest Airlines (NWA) Flight #305, departed [guess: from] Seattle-Tacoma International Airport (Sea-Tac), under hi[guess: jack] jack 11/24/71, at 7:36 PM. At the orders of the hijacker, the landing gear and flaps were down. After the plane was airborne, the hijacker and Stewardess [REDACTED] discussed the opening of the rear door and the lowering of the air stairs. In less than five minutes after take-off, the hijacker instructed Stewardess [REDACTED] to go forward into the First Class Section and close the curtain behind her and not to return to the rear compartment again.
At 7:42 PM, the crew advised that the stair light was on, indicating that the hijacker was doing something with the air stairs. The plane, at that time, was flying at 7,000 feet.
The log contained an entry at 8:05 PM, indicating the crew had on two occasions, attempted to make contact with the hijacker but he did not reply. However, he then spoke over the PA system and said "everything is okay."
An analysis on 11/24 and 25/71, of the flight path of the aircraft, after it left Seattle, and the logs provided by NWA, suggested that the hijacker was still in the airplane as of 8:05 PM. At that time the plane, according to radar tracking by the U.S. Air Force, was located at a point north of the Pidgeon Springs, Washington area and east of Ostrander, Washington. This would, we been the northarch most point when he was known to be on the aircraft.
At 8:11 PM, according to a log maintained by NWA, the crew reported that they were "getting some oscillations in the cabin, must be doing something with air stairs." An analysis as to the cause of this oscillation, also referred to as a "pressure bump" or "change in the cabin pressure" pointed to the probability that it was caused by the hijacker leaving the aircraft.
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DB Cooper-24995
SE 164-81
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On 1/6/72, the NWA 727 which was actually involved in the hijacking, was flown to Seattle, by [REDACTED] b6 for the purpose of conducting a test to see if the "pressure b7C bump" experienced during the hijacking, was caused by some- thing leaving the aircraft.
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The conclusion from that test was that the cabin pressure change occurred when the stairs were forced upward by the air pressure after the weight had been removed. according to [REDACTED] who was a member of b6 the hijacked crew, and also a member of the crew when b7C the test was performed, the occurrence was identical with the incident on the night of the hijack. Also the instrument in the cabin which reacted so violently on the night of the hijacking, also reacted the same way when the test was performed.
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[REDACTED] based on the test flight above, b6 then prepared a memo showing the steps by which he arrived b7C at the best probable bail out point of the hijacker, and plotted this area on a map. This information is set forth as follows:
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[illegible - appears to be a faint map or diagram with scattered dots and markings]
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DB Cooper-24996
Serials: SE 164-81