One revelation made during the hearing was that both pilots in the Ethiopia and the Indonesia crash received stick shaker
alerts, a warning that urges the pilot to return to the airport of origin due to an imminent engine stall in the plane.
The air speed, attitude, and altitude displays, together with the stick shaker
, are the primary flight information indicators in the flight deck.
Throughout the brief flight, an ominous rattle could be heard on the voice recorder, evidence that a device called a stick shaker
was clattering to alert the pilots of a potential stall that could lead to a crash, said Ony Soerjo Wibowo, an air safety investigator.
Information retrieved from the flight data recorder showed the "stick shaker
" was vibrating the captain's controls, warning of a stall throughout most of the flight.
Wooden stick shaker
type rattles strung with deer hooves or dewclaws were once fairly widespread among the Ojibwe and Potawatomi peoples of the North American Great Lakes region.
The stick shaker
, which warns the pilots of an imminent stall, activated three times before the co-pilot brought the flight into a descent of 500ft in order to pick up speed.
The loss of power and inappropriate flight control inputs generated a series of stall warnings, including the activation of the stick shaker
The control column immediately went into "stick shaker
," warning of an impending stall.
During testing, the stall warning system (stick shaker
attached to the yoke) and stall protection system (stick pusher that provides automatic stall recovery) were evaluated.
Before the actual stall, with the first horn, light or stick shaker
(depending on the airplane), level the wings, decrease the angle of attack a bit, apply full power and clean up as speed returned.
Less than five seconds before impact, the stick shaker
By the time a stall warning known as a "stick shaker
" activated on the Asiana flight, the pilots were unable to abort the landing.