"Pink": abreviated PNC, Procedural Non-Compliance. NTSB staff-managers' repeated "pink" blocked retraction of AAR-81-8 for decades.
Dec' 24th 2015: latest revision to NTSB "Rules of Practice" failed to correct these built-in organizational-weaknesses,
ERA12RA367A . . . collided in flight in the vicinity of Sumerduck, Virginia. . . . Under the provisions of Annex 13 to the Convention on International Civil Aviation and by mutual agreement, the United States delegated the accident investigation to the government of Canada. The NTSB designated an accredited representative to the investigation on behalf of the United States, and the FAA designated an advisor to the accredited representative.
The investigation was conducted by the Transportation Safety Board of Canada under its statutes.
A review of this investigation, delegated to a different country's "investigating authority", was presented by Jon Lee, at ISASI's Vancouver gathering in 2013:
Steenblik, J.W. "A New Look at TWA Flight 841: With ... new analysis, ALPA petitions NTSB to revise ... report on the B-727 spiral dive in 1979." _Air Line Pilot_ . 60:1 (January 1991), 24-27.
Some credit goes to The Boeing Company -- their tight control of some investigations, subtly stacking-the-deck, has been impressive to all investigators.
Learmount, D. "Fragile credibility: Accident investigations ... should strive for ... objectivity ..." Flight Int'l (26March - 1April, 2002), 5.
"Changing the Past ... investigations reports ... should be revised." Flight International (1-7October 2002), 3. \\ http://www.flightglobal.com/pdfarchive/view/2002/2002 - 2879.html?search=Changing the Past
Failure - Interactions
(Though costs for the manufacturer were thus minimized.)