The Safety Board determined that the probable cause of this incident “was a manufacturing defect in a clutch mechanism that prevented the speed brakes from automatically deploying after touchdown and the captain's failure to monitor and extend the speed brakes manually. Also causal was the failure of the thrust reversers to deploy when initially commanded. Contributing to the incident,” said the Board, “was the captain's failure to confirm speed-brake extension before announcing their deployment and his distraction caused by the thrust reversers' failure to initially deploy after landing.”

Based on those findings, the Safety Board recommended the FAA:

Require all operators of existing speed-brake-equipped, transport category airplanes to develop and incorporate training to specifically address recognition of a situation in which the speed brakes do not deploy as expected after landing.

Require all newly certified transport category airplanes to have a clearly distinguishable and intelligible alert that warns pilots when the speed brakes have not deployed during the landing roll.

Require Boeing to establish guidance for operators and pilots of all relevant airplanes to follow when an unintended thrust-reverser lockout occurs.

The NTSB also reiterated recommendations to the FAA arising from earlier investigations and attached them to this report. They include:

Establish best practices for conducting both single and multiple emergency and abnormal situations training.

Once the best practices for both single and multiple emergency and abnormal situations training have been established, require that these best practices be incorporated into all operators' approved training programs.

Require that all pilot training programs be modified to contain modules that teach and emphasize monitoring skills and workload management and include opportunities to practice and demonstrate proficiency in these areas.