MD-11 Flight Crew Operations Manual
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Landing Gear and Brakes -
Description and Operation
Land.10.3
Gear Indicating and Warning
The landing gear position indicating system consists of lights, aural warning,
mechanical indicating, and indications shown on the SD.
Two separate systems provide gear position and warning indications. Indication
and warning lights for one system are installed adjacent to GEAR handle. Inputs
from the second system are shown on the SD. Either system can be connected to
the display adjacent to GEAR handle. This is done by reversing the output signal
connectors in the avionics compartment.
Both indication displays will show a separate green indication for each landing
gear when gear is down and locked. It will also show a separate red indication for
each gear when a gear is not in a position that corresponds with the GEAR handle.
With the GEAR handle in the DOWN position, both indication systems will
display an unsafe condition if the down-lock links are not over center.
With the GEAR handle in UP position, both indication systems will display an
unsafe condition if either main gear door is not closed and latched or the nose and
centerline gear are not in the retracted position with lock links over center.
The gear warning horn will sound when any throttle is retarded to idle with the
landing gear up, the airspeed below 210 knots, and radio altitude 1200 feet or less.
The warning horn can be silenced with the GEAR HORN OFF button on the
forward pedestal.
The primary system is responsible for the gear warning horn. The secondary
system is responsible for green box indication on the secondary display. The nose
gear primary system is responsible for the TOO LOW GEAR aural warning.
The gear warning horn will also sound any time any gear is not down and locked
and the flaps are extended 31.5 degrees or more. In this case, the horn cannot be
silenced with the GEAR HORN OFF button.
When the CTR GEAR NORM/UP switch is in UP and the center gear is up and
locked, the CTR gear light will remain off during any subsequent gear warning.
The center gear position will not input to the aural warning.
With the CTR GEAR NORM/UP switch in UP and the center gear in the down
and locked position, the green and red indicator lights will illuminate based on the
agreement/disagreement status with the GEAR handle position.
Both indication systems function in the normal manner when the alternate control
system is used for gear extension.
October 02, 2006
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