excess of 10 percent over the rated capacity is applied.
Hoisting Restrictions
For example, the safety valve on a 10-ton jack will
There are many restrictions to hoisting for each
bypass fluid at 11 tons of pressure.
type of aircraft. Most hoisting restrictions are the same
Axle Jacks
as for jacking aircraft. If you violate any of these
restrictions, there is a good chance that you will have an
Use axle jacks for raising one main landing gear or
accident, damage the aircraft, or injure someone. The
the nose gear of an aircraft for maintenance of tires,
restrictions generally concern aircraft gross weight and
wheels, and struts. There are four different types of axle
configuration. Some of the considerations are access
jacks and many different sizes (lifting capacity in tons).
(stress) panels on or off, external stores on or off, and
The smaller hydraulic axle jacks are normally squadron
wings, folded or spread.
or unit permanent custody equipment. That means your
There are many factors that can affect the safety of
outfit is responsible for making sure the jacks are load
the aircraft and personnel during hoisting operation.
tested at the support equipment (SE) division of
For details on restrictions and for the proper installation
the Aircraft Intermediate Maintenance Department
of any sling, consult the applicable MIM. Don't forget
(AIMD) before being put into service, and annually
that many squadrons have their own local standing
thereafter. Special inspections include 13-week inspec-
instructions for hoisting aircraft that contain additional
tions at AIMD SE, but a load test is not required every
safety precautions and restrictions. You must know
13 weeks. A record of maintenance, inspections,
these precautions and restrictions as well.
technical directives, and load testing is kept on OPNAV
Prior to carrier operation, aircraft hoist points are
Form 4790/51.
inspected for serviceability and easy access in an emer-
All model designations for axle jacks begin with
gency. For details on how to accomplish this inspection
the letter A, for axle, such as A10-1HC. The number
on your aircraft, consult the applicable MIM.
following the A shows the jack capacity in tons, such as
Q1-34.
What are the four types of aircraft slings?
10 for a 10-ton jack. This is followed by a dash (-) and
Q1-35.
What is the most common type of aircraft
the specific jack identification number. Then comes
lifting sling used today?
two letters that show the type of jack (HC = hand
carried, HS = horseshoe, TB = T-bar, and OR =
Q1-36.
What types of slings do not contain flexible
outrigger). The four types of axle jacks are discussed in
components?
the following text.
Q1-37.
What manual covers load testing and
inspection information for aircraft slings?
HAND CARRIED.--These axle jacks (fig. 1-26)
are portable, self-contained units, with single or double
Q1-38.
How often should inspection and lubrication
of aircraft slings be accomplished?
AIRCRAFT JACKING
LEARNING OBJECTIVE: Recognize the
procedures for the safe raising and lowering of
aircraft by the proper use of aircraft jacks.
Identify the various types of jacks presently
found in the naval inventory.
The following text will familiarize you with the
various types of jacks, their use, and general safety
procedures. You will become familiar with jack
identification, preoperational inspections, and jacking
procedures.
JACK IDENTIFICATION
All aircraft hydraulic jacks are either axle or
airframe (tripod) jacks. These jacks use standard,
authorized aircraft hydraulic fluid. They have a safety
bypass valve that prevents damage when a load in
Figure 1-26.--Hand carried axle jack.
1-29
