Document date 8 December 1971AIDates: machine-written — generated by an AI model from the transcripts, and it can be wrong. The scan is the source; the transcript is machine-generated from it.
Another copy of this document is the primary, most legible copy: read it.
FBI 164-81, Vault Part 100 p. 61 (DB Cooper-44974), Memo, dated 8 Dec 1971 — cooper.theunsolved.net/parts/Cooper-Part-100/pages/61
Transcript
The scan is the source; the transcript is machine-generated from it.
SE 164-81
---
[REDACTED — b3, b6]
---
On the 727, the rear stairs cannot be lowered from
the pilot's compartment. They can be lowered only from the
passenger compartment in the rear of the plane or externally
if the plane is on the ground.
[REDACTED — b6, b7C] advised that once the operation of the rear
stairs has started there is no way to stop them until they
have extended to the full position. On the ground when the
rear stairs are extended, the weight of the stairs actually
carries them to the full open position. If the stairs are
extended in flight, the pressure of the wind keeps them from
opening to the full position.
On several occasions [REDACTED — b6, b7C]
[REDACTED] extended the rear stairs while in flight.
This was done at speeds of approximately 150 knots. Opening
the rear stairs in flight at speeds at 150 to 170 knots would
not suck any items from the passenger cabin. There would be
a slight change in pressurization but this would not remove
any papers or cushions from the passenger cabin.