Page:Aircraft Accident Report for 1972 Sacramento Canadair Sabre accident.pdf/19

 three times higher than that of the test Sabre Mark 5 aircraft, yet N275X reached a velocity of more than 130 knots in an exaggerated takeoff attitude twice on the 5,000-foot runway. Apparently, both times the aircraft remained airborne in ground effect as long as the pilot maintained the excessive noseup control input. Each time he relaxed the back pressure on the yoke the aircraft settled to the runway.

The overrotation was undoubtedly a function of (1) a lack of familiarity with the Sabre Mark 5 and (2) the effect of visual cues at Sacramento as opposed to Oakland. The pilot had logged a total of 3.5 flying hours in N275X, but claimed an additional 4 hours which were not logged. The only other "swept wing" experience he had was 31 hours logged as second-in-command in a Lockheed Jetstar. The remainder of his jet experience was accumulated in a Lear Jet as second-in-command. Although all jet experience provides a measure of exposure to the faster acceleration, and consequently to the quicker reactions required, very few models of aircraft are more sensitive to overrotation than Sabre-type aircraft. In this respect, the high thrust/weight ratio and relatively lower elevator qowerpower [sic] of the Lear Jet may have developed habit patterns which would increase the tendency of overrotation in the Sabre. For example, the Sabre Mark 5 has a lower thrust/weight ratio than the Lear Jet, but more effective elevator power at slow speeds. This combination results in the ability of the Sabre Mark 5 to achieve high angles of attack before flying is attained, with insufficient thrust to overcome the induced drag generated by the attitude. The application of excess noseup control in the Lear Jet, prior to reaching flying speed, generally does not result in an overrotated condition because the airspeed increases faster than the elevator effectiveness.

A second, and perhaps more significant factor, is the previously mentioned visual cues. The pilot was accustomed to establishing a takeoff attitude by reference to the environment around Runway 29 at Oakland, where the "wide open" expanse of San Francisco Bay creates a very indefinite horizon. This results in the visual impression of an "unlimited" runway. Actually horizon would appear to recede as the aircraft moved along the runway. Under these circumstances, takeoffs by the inexperienced pilot were accomplished with little likelihood of overrotation. Although the pilot established a takeoff attitude by reference to the amount of runway remaining, the actual lift-off attitude by the length of the runway and the sensory illusion that the end of the runway was still quite distant.

In contrast to the environment at Oakland, Runway 30 at Sacramento is closely surrounded by trees, buildings, water towers, and other objects which create a well-defined horizon. During this takeoff—the pilot's first from another runway in the Sabre—the short length of the