The XF10F Jaguar test program says 'hi'

Test pilot Corwin "Corky" Meyer, the only pilot to fly the Jaguar,[4] described it as entertaining to fly "because there was so much wrong with it."[5] Examples of the "wrongness" encountered by Meyer during the test flight program included:

• Jamming of the wing sweep mechanism as hydraulic fluid congealed into a gelatinous state from poor maintenance, resulting in a substance with "a consistency of Jell-O". Despite this failure, the aerodynamicist's assertion that the wing would unsweep itself in case of a mechanical failure proved entirely correct, to Meyer's relief.
• Regular inflight failures of the equally experimental Westinghouse XJ-40 turbojet. The reason for its unreliability within the Jaguar was traced ultimately to an extraordinary case of sloppy manufacture; an engine electronics box access panel had a screw nearly 5 in (127 mm) long mangling the delicate circuits within, in sharp contrast to the other three panel screws which were barely .4 in (10 mm) long.
• The "aerodynamically balanced" canard-actuated pendulum elevator, whose ineffectiveness and poor contribution to stability was already apparent in free-flight development models. The instability was dismissed as a "model effect", but this proved to be a fallacious judgement. Initial fixes consisted of a set of triangular horizontal fins on the rear fuselage, but ultimately Grumman admitted defeat and retroactively fitted the horizontal surfaces from the earlier Grumman F-9 Cougar swept-wing fighter. By this time the program was nearing its end, and it was at this stage unlikely that the U.S. Navy would adopt the Jaguar.
• During a flight the canopy opened and could not be closed, nor could it be ejected. At the same time, the less-than-trustworthy engine began losing power at an alarming rate, but, due to the problems with the canopy, Corky Meyer could not eject. He did manage to land safely. It was just after this flight that the aforementioned grossly oversized screw was found.