Figure 4-58.—Tensioner cylinder assembly location.
Bridle Tensioner Limit Switches
There are two limit switches in the bridle tensioning
system. Both switches (fig. 4-57) are located in the
aftermost trough cover, and they are actuated by a cam
on the bridle tensioner piston rod support. One switch
is actuated when the tensioner is fully aft (full in) and
the other is actuated when the tensioner is fully
extended (full out). The fully aft limit switch, when
actuated,
allows completion
of the RETRACT
PERMISSIVE circuit. This prevents retraction of the
grab and shuttle into an extended bridle tensioner. This
limit switch is also part of the MANEUVER AFT
circuit. This circuit ensures that the tensioner piston is
fully aft, allowing the grab latch to remain locked to the
shuttle in an aircraft-launch-abort situation.
The fully extended limit switch, when actuated,
prevents completion of the MILITARY POWER circuit.
This guards against mispositioning of a bridle- or
pendant-launch type of aircraft. This limit switch may
be removed on installations without an installed bridle
arrester and holdback cleat.
Holdback Cleat Installation
The holdback cleat installation provides a means of
holding the aircraft in place during bridle tensioning
with bridle- or pendant-launched aircraft. It is installed
in the deck directly behind the bridle tensioner. Cutouts
along the entire length of the cleat permit attachment of
different-length aircraft. When the catapult is inactive,
the slot in the holdback cleat is covered with a slot seal.
A link, coupled to a holdback unit attached to the
aircraft, is inserted into the appropriate cutout. All other
cutouts are filled with filler blocks to prevent the link
from dropping into the wrong cutout when the aircraft
is maneuvering forward into launching position. When
the catapult is fired, a tension bar or ring in the
holdback unit breaks, releasing the aircraft. A retaining
block is inserted in the cutout with the holdback link to
prevent ejection of the holdback link from the deck
cleat during aircraft launching.
Bridle Arrester System
The bridle arrester system absorbs the
momentum of the bridle, which may weigh as
forward
much as
200 pounds, arrests it without causing damage to
aircraft or injury to personnel, and retains it on board
when the aircraft becomes airborne. For description and
operation of the bridle arrester system, refer to
NAVAIR 51-5-27.
Aircraft Weight Confirmation Unit
The aircraft weight confirmation unit (fig. 4-59)
provides a visible five-digit readout of the aircraft
weight during day and night catapult operations. The
first and second digits are adjustable from zero through
nine; the third digit is adjustable to either zero or five;
and the fourth and fifth digits are fixed at zero. It is
4-46
