From Page 40
In addition to DT, there is also Operational Testing or OT.
the difference between DT and OT?
(1) There is no difference in concept between DT and OT. The Army uses the
term DT, while the Navy uses OT. Turn to Page 59.
(2) DT is primarily concerned with hardware design criteria, while OT is
primarily concerned with personnel training requirements. Turn to Page 71.
(3) DT demonstrates hardware design effectiveness, while OT estimates
whether the design can be used effectively. Turn to Page 78.
From Page 21
(2) It's true that no mention of seat belts is made in this paragraph, but
in paragraph titled "Seat Belts" there is specific guidance; their use is
not left to the discretion of the designer. Return to Page 21.