MD-11 Flight Crew Operations Manual
k
Flight Controls -
Description and Operation
Flt.10.2
An inboard section of each inboard elevator can be detached mechanically from
the remainder of the elevator segments to rotate the tailcone under the airplane
during engine 2 removal. Two manually operated pins for each section lock the
segments in the normal position for flight.
A tandem hydraulic actuator, powered by two independent hydraulic systems,
combines in pairs to provide full flight envelope hinge movement in the event any
single hydraulic system failure occurs. Sufficient power capability to maintain
flight is available with the loss of any two systems.
The actuator valves (surface position) are controlled mechanically by movement
of the control columns in the cockpit. The two cockpit control columns are
mounted on a common torque tube.
Elevator Load Feel System
The Elevator Load Feel (ELF) system is a self-monitored, dual channel system. A
spring-type, variable load-feel mechanism provides a simulated feel of elevator
aerodynamic loads. The ELF mechanism acts as a centering device to return the
control columns to neutral when released from an off-neutral position. ELF
functions are performed by the Flight Control Computers (FCCs). In the event of
failure, a brake is applied to the ELF actuator in the failed channel. The remaining
channel of the dual channel system maintains uninterrupted EFL system control.
With the ELEV FEEL selector in the AUTO position, the ELF system regulates
the control column force per degree of column rotation as a function of airspeed.
The ELF actuator may be operated in the manual mode by pulling the ELEV
FEEL selector out and holding the selector in either HI or LO until the desired
ELF speed appears on the configuration page of the SD. The ELEV FEEL
MANUAL amber light illuminates.
The SEL ELEV FEEL MAN level 2 alert will be displayed to indicate failure of
the dual channels of the ELF system. The ELEV FEEL MANUAL level 1 alert
will be displayed to indicate manual selection of the ELEV FEEL selector. In the
case of ELF dual channel failure, the SEL ELEV FEEL MAN level 2 alert will be
replaced by the ELEV FEEL MANUAL level 1 alert upon ELEV FEEL selection
to manual.
October 02, 2006
To Next Page