ROTORCRAFT FLIGHT MANUAL
CSP-HE/HS-1
Emergency and
Malfunction Procedures
MD 500
(Models 369HE/HS/HM
)
Revision 6
3-22
FAA Approved
Conditions:
Runaway trim
Indications:
An uncommanded longitudinal or lateral cyclic trim actuation. The cyclic
may move to a full travel position or some intermediate position resulting
in cyclic forces up to the maximum. Uncommanded movement can occur
after cyclic trim switch actuation or as a result of an electrical short.
NOTE
:
Runaway cyclic trim failures can produce cyclic stick forces of approximately 30
pounds in the direction of the runaway. Although the forces required to move the
cyclic will be higher than normal, the helicopter will respond normally to all cyclic
inputs by the pilot.
Procedures:
F
Establish a safe flight condition that produces the least cyclic control
force.
NOTE
:
If a forward longitudinal runaway trim failure is experienced, it may be possible
to reduce cyclic stick forces by maintaining higher airspeeds. Cyclic stick forces
may be reduced if an aft longitudinal runaway trim failure is experienced by
maintaining slower airspeeds. Lateral runaway trim forces cannot be reduced by
adjusting flight conditions.
F
Utilize left hand and legs, as necessary, to apply pressure against the cy−
clic stick to relieve the right hand loads and conserve strength for land−
ing. Use collective friction to prevent unwanted collective movement and
associated power change. Be prepared to respond to any emergency re−
quiring the use of collective pitch.
F
Actuate the trim switch thru all positions, several times if necessary, as
this will generally re−establish trimming capability. When restored, trim
to a near neutral position and land as soon as practical avoiding further
trimming.
F
If trim runaway is to the full forward position, accomplish landing into
the wind and do not hover downwind.
