I often write about the NTSB's "party system." That's the NTSB's practice of asking airlines and manufacturers for help in determining an accident's cause. If you ask me, it's a bit like asking the fox for help in figuring out what happened to the chickens. The party system allows industry participants to bias NTSB probable cause findings in their favor.
The NTSB allows party participants to handle evidence and perform certain engineering tests. But one thing the NTSB insists on doing all by itself is downloading the data from an aircraft's black boxes. The NTSB's labs in Washington DC are well equipped for that job, and it doesn't require any "help" from the airlines.
The Safety Board learned that the recorders were flown to Tulsa, Okla., where American Airlines technicians downloaded information from the DFDR. . .
Because maintaining and enforcing strict investigative protocols and procedures is vital to the integrity of our investigative processes, we have revoked the party status of American Airlines and excused them from further participation in this incident investigation.