Tronair 01-0597-0000, Operation & Service Manual, Page: 15 / 21

INS-1582
Towbar Usage Instructions
11/2003 – Rev. 03
- 5 -
USAGE PROCEDURE (continued)
Type Of Coupler:
Damage to the towbar or aircraft can result while towing with the following type of couplers:
- Lift Head - Vertical Side Swing Latch
- Standard Duty Latch - Swivel Hook
These types of couplers are known to cause binding and failure in the eyebolt. Indicators of eyebolt binding are wear on the
outside diameter of the eye and indentations on the inside diameter. The failure will begin at the head of the eye.
See Figure 6.
Figure 7 illustrates a pintle hook arrangement that is known to eliminate
eyebolt binding. Tronair recommends using this type of hook on your tug.
Eyebolt and Pintle Pin Size:
Damage to the towbar or aircraft can result by towing or pushing an aircraft
with an incorrect size eyebolt or pintle pin. A correct size eyebolt will make
contact with the pintle pin. A gap between the eyebolt outside diameter and
the coupler face plate should be easily seen. An eyebolt which is too large
will cause the eyebolt to make contact with the face plate of the coupler.
When the eyebolt is too large for the coupler, a gap between the inside
diameter of the eyebolt and the coupler face plate will be seen.
See Figure 8.
To ensure proper towing and pushing, check to make sure that the pintle
pin diameter is not too large for the eyebolt's inside diameter.
Approximately a one-half inch (1/2") gap between the pin diameter and the
eyebolt should be seen. If any of these conditions are not met, please
contact Tronair for information to obtain a new coupler.
Towing Angle:
Damage to the towbar or aircraft can result from pushing an aircraft while
maintaining too sharp of an angle between the tug and the towbar. Contact
between the towbar weldment and tug must be avoided. It is recommended
that the angle between the tug and towbar not exceed 90º.
See Figure 9.
FIGURE 9
FIGURE 8
FIGURE 7