Piper PA-24 Comanche, Руководство по обслуживанию

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PIPER COMANCHE SERVICE MANUAL
II - HANDLING AND SERVICING 04/01/09
1B20
(3) The friction drag torque can be determined as follows: Run the nut down to near contact (but
not in contact) with the bearing surface and check the "friction drag torque" required to turn
the nut.
NOTE: Check the friction drag torque by attaching a scale type torque wrench to the nut and
determining the torque required to turn the nut on the bolt. (Before the nut makes
contact with the bearing surface.)
(4) The friction drag torque (if any) shall be added to the desired torque specified in Table II-IIA,
Sheet 1. This final torque should register on the indicator or be the setting for a snap-over
torque limiting device.
(5) Torque requirements do not apply to cross recessed or slotted screws or to fasteners installed
into rivnuts, pressnuts or other nuts not designed to rotate for wrenching at the fastener unless
otherwise specified in the subject chapter/section.
(6) Fasteners listed in Table II-IIA installed into nutplates, and which are accessible to be torqued
at the fastener, must be tightened to the low end of the torque range specified in the appropriate
“shear” column. Torque requirements do not apply if the fastener can not be torqued due to
torque device accessibility.
NOTE: When the fastener is stationary and the nut is torqued, use the lower side of the torque
range.
When the nut is stationary and the fastener is torqued, use the higher side of the torque
range. In this case, ensure one (1) washer is installed under the head as follows:
(a) If the subject chapter/section does not specify the use of a washer under the head,
install one (1) NAS1149 .032 thick washer under the head. If additional washers
are required under nut to adjust for grip length variation as described under
Threaded Fastener Installation in 2-7b: reduce them .032 to allow for the
additional .032 washer now installed under head. Check to ensure threads are not
bearing loads, due to the added .032 washer thickness.
(b) All added washers are to be of the correct diameter, material and finish that
matches the fastener being installed.
(7) Apply a smooth even pull when applying torque pressure. If chattering or a jerking motion
occurs during final torque, back off and re-torque.
(8) When installing a castellated nut, start alignment with the cotter pin hole at minimum
recommended torque, and do not exceed maximum recommended torque. If the hole in the
fastener shank and the nut castellation do not align within this range, change washers and try
again. Do not exceed the maximum recommended torque. If self-locking castellated nuts are
used, include friction drag torque.
(9) Unless otherwise specified in the subject chapter/section, when castellated nuts are used with a
cotter pin on moving joints, the nut shall not be torqued to Table II-IIA values. Nuts shall be
tightened to remove looseness in the joint and then the cotter pin installed.