Despite reassurances from the NTSB that their long investigation wasn't "fixed",
the pilots felt otherwise about the USA's officially "independent" Safety Board.
The manufacturer stacked-the-deck:
to call-out against the cards-dealt,
and too awed to reject the erroneous Boeing Scenario.
Masses of data, from "simulator trials" and from an Oct'80 Flight Test,
with selective data-dredging by Boeing engineers,
swamped the Safety Board's struggling staff-engineers:
Staff investigators thus looked-past the direct evidence
(Wreckage Examination, Trail of Debris, pilots' testimony, mishap-FDR-data),
instead glorifying data fabricated after the accident
at manufacturer's facilities.
. . .
from Capt. McIntyre (ALPA party coordinator) relating
confrontation with IIC Kampschror at the
Boeing Meeting in Seattle for the flight test.
[The IIC later excluded this letter from the NTSB's docket.]
Lessons from the Boeing-led
Night FL390 CRZ Yaw x Roll = DIVE
B727 N840TW, TWA 841 4Apr'79
Failure - Interactions
The tendency to search for or interpret information in a way that confirms one's preconceptions. . . . discredit information that does not support their views. . . .