SECTION 7
DESCRIPTION
SOCATA
MODEL TB 20
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© 1988, 1991, 1992, 1994 to 1996, 1997, 2000 -
socata
- All rights reserved
June 30, 1988
Revision 8
7.21
LANDING GEAR OPERATION
To retract or extend the landing gear, pull out on the gear lever and move it to
the desired position. During a normal cycle, the gear retracts fully or extends
and locks, limit microswitches close and green indicator lights illuminate
(down cycle only), indicating completion of the cycle.
While the gear is in transit , or whenever any gear is not fully retracted or
locked down, the red gear unlocked light will illuminate.
The electric pump will continue to run :
–
during landing gear extension, until the green indicator lights illuminate
and the red indicator light goes out ;
–
during landing gear retraction, until the green and red indicator lights go
out.
If pressure in the system drops, the pressure switch starts operation of the
hydraulic generator which increases pressure.
During cruising flight with the landing gear retracted, automatic cycling on the
hydraulic pump motor to restore system pressure bleed down may normally
occur a few times per hour. Frequent cycling is an indication of an abnormal
pressure loss and the cause of such condition should be investigated.
The safety (squat) microswitches, actuated by the main gears, electrically
prevent inadvertant retraction whenever the gear shock–absorber is
compressed by the weight of the airplane. A pull–off type circuit breaker is
also provided in the system as a maintenance safety feature. With the circuit
breaker pulled out, landing gear operation by the gear pump is prevented.
After maintenance is completed, and prior to flight, the circuit breaker should
be pushed back in.
