CHAPTER 3
MK 7 AIRCRAFT RECOVERY EQUIPMENT AND
BARRICADE SYSTEMS
Present-day aircraft normally require the use of
runways that are 5,000 to 8,000 feet long in order to
land ashore. On an aircraft carrier, these same
aircraft are stopped within 350 feet after contacting
the deck. This feat is accomplished through use of
aircraft recovery equipment, including an emergency
barricade that brings a landing aircraft to a
controlled stop by absorbing and dispelling the
energy developed by the landing aircraft. This
recovery equipment is commonly called arresting
gear. Figure 3-1 shows the general arrangement of
a typical Mk 7 arresting engine.
When you complete this chapter you should be
able to do the following:
Explain the operations and functions of the
arresting gear engine systems during recovery
operations.
Describe procedures for removing and
replacing crossdeck pendants.
Identify procedures for attaching barricade
webbing to the stanchions.
Describe procedures for derceving and
rereeving arresting gear engine purchase cable.
Identify procedures for preparing, pouring,
and conducting proof-load tests on wire rope
terminals.
COMPONENT DESCRIPTION
AND OPERATION
The sole purpose of an aircraft carrier is to
provide a means of launching a strike against an
enemy anywhere in the world within the strike range
of our aircraft. After the aircraft complete their
mission, the carrier must provide a means of safely
recovering them The Mk 7 arresting gear provides
this means.
The three major systems that make up the Mk
7 recovery equipment are as follows:
1. Emergency recovery equipment
2. Drive system
3. Engine installation
Aircraft arrestments aboard carriers are
classified as either a normal arrestment or an
emergency arrestment. Simply stated, arrestment is
accomplished in the following manner: the arresting
hook of the incoming aircraft engages a wire rope
cable, called a deck pendant, that spans the flight
deck in the landing area. The force of the forward
motion of the aircraft is transferred to purchase
cables that are reeved around a movable crosshead
of sheaves and a fixed sheave assembly of the
arresting engine. The movable crosshead is moved
toward the fixed sheave assembly as the aircraft
pulls the purchase cables off the arresting engine,
forcing a ram into the cylinder holding pressurized
hydraulic fluid (ethylene glycol). This fluid is forced
out of the cylinder through a control valve that
meters the flow to an accumulator until the aircraft
is brought to a smooth, controlled arrested landing
(see figs. 3-2 and 3-3).
After arrestment, the aircraft’s arresting hook is
disengaged from the deck pendant. A retract valve
is then opened, allowing fluid to be forced from the
accumulator back into the engine cylinder, forcing
the ram out. As the ram moves out of the cylinder,
the crosshead is forced away from the fixed sheave
assembly, pulling the purchase cables back onto the
engine until the crosshead is returned to its
BATTERY position and the crossdeck pendant is in
its normal position on the flight deck.
An emergency arrestment is accomplished in the
same manner as a normal arrestment except that a
barricade webbing assembly transmits the aircraft’s
landing force to the purchase cable instead of a
crossdeck pendant.
We will also discuss the
3-1
