generally appears when a V-ring packing has been
replaced, but it usually ceases after operation. If
leakage persists after operation, the packing may have
unseated itself and the gland should be readjusted. If
leakage persists after a reasonable adjustment,
disassemble and check the stuffing box walls and the
pistons for scoring, and check the packing for damage.
Leaking packing must be replaced when adjustment
does not stop the leakage. Excessive gland pressure
must not be applied. V-ring packing under pressure
from the gland not only functions improperly or wears
out faster but also applies uncalculated forces on the
ram, shaft, or piston, which may cause improper
operation of the machinery. A clearance of 1/64 to 3/64
inch must be maintained to allow the packing freedom
of movement. When there is clearance between the
body and the gland flange, check the clearance at four
points, 90° apart, to ensure that the packing or gland is
not cocked before installing the gasket.
REVIEW QUESTIONS
Q13.
What is the minimum allowable clearance
between the crosshead and the crosshead
stop?
Q14.
What is the age of all packing based on?
Q15.
What is the shelf life of V-ring packing?
Q16.
When installing V-ring packing, what side
faces the pressure?
SAFETY PRECAUTIONS
LEARNING OBJECTIVES: List the safety
precautions
associated
with
topside
and
deckedge areas. List the safety precautions
associated with the arresting engine below
decks. List the safety precautions associated
with
maintenance
of
aircraft
recovery
equipment.
Safety is not an accident. Safety is the result of
trained personnel knowing their jobs and doing those
jobs to the utmost of their ability. Attention to every
detail, concern over every function, and awareness of
malfunction will nullify the possibility of accident from
improper operational procedures. Mechanical failure
cannot be completely neutralized, but trained personnel
can make such a failure a rarity.
Recovering aircraft involves various inherent
dangers, due to the complex coordination of personnel
and machinery. Personnel engaged in the operation of
the arresting gear equipment must be thoroughly
trained and indoctrinated in the operations. Disregard
for the fundamentals of caution and safety creates
hazards far in excess of the previously mentioned
inherent danger factors.
All operating personnel must understand the
importance
of
accurate
commands,
attention
to
commands, and proper care of communications
systems. The system may be phones, synchro signals,
or lights, and must be operational at the time of use.
Accuracy in making proper settings of gears, indicator
systems,
tension,
and
pressure
tests
must
be
emphatically impressed on all personnel.
The following general safety observations are
arranged according to location, and copies should be
supplied to all applicable stations.
TOPSIDE AND DECKEDGE AREAS
During arrestment, all topside and deckedge
personnel should be aware of all movement on and
about the deck, with strict attention paid to the landing
aircraft. Deckedge control operators should duck below
deck level during pendant arrestment in the event of
pendant breakage or failure that would cause cable
whip or the aircraft to go over the deck edge.
Hook Runners
Hook runners should approach aircraft from the
front and side. This will place them away from danger
of jet blast or broken cable backlash.
Overcrowding
Catwalk personnel should be held to a minimum so
they can exit quickly should they be placed in jeopardy.
Barricade Readiness
Rapid fuel consumption by jet aircraft requires
highly trained, responsible crews for rigging the
barricades. Regular drills in rigging should be held to
reduce rigging time to a minimum.
Walkback
Air in the main engine cylinder or the CRO valve
does not seat properly are the major causes of
walkback. This is an extremely dangerous occurrence,
as the pilots have no control over the aircraft in addition
to being unable to see where they are going, thus the
aircraft
may
go
overboard,
endanger
deckedge
3-60
