Aircraft wheels consist of two forged half-wheels (called Hub Assembly) made of light alloy. They are attached together with bolts which are made of high tensile steel and self-locking nuts. An O-ring seal is used between the two half-wheels to prevent air leaks.
The wheels are equipped with:
- Taper roller bearings with protective seals,
- Drive keys for the brake rotor disks,
- Fuse plugs which deflate the tyre in the event of excessive brake overheat and thus protect against tyre burst because of excessive pressure,
- One standard inflating valve which can be replaced by a valve with an incorporated pressure indicator (PSI type), and
- A provision for installation of a transducer for the tyre Pressure Indicating System (this is an optional system, not in all aircraft).
Tyre Mounting on Aircraft Wheels
Currently, most of the airliners using TUBELESS RADIAL TYRE, So let’s go through tubeless tyres mounting procedure.
A new O-ring seal with the correct part number should be used at each tyre change following the wheel manufacturer’s specifications.
Check for word “TUBELESS” on sidewall.
Check for word “RADIAL” on sidewall.
Do the proper inspection and make sure tyre is clean inside.
Clean the bead base with a cloth dampened with denatured alcohol then allow the bead seat area to dry.
Align red balance dot on the tyre with wheel valve or wheel heavy point (if indicated on the wheel). If no red dot appears on the tyre, look in the liner for a balance pad and align this area to the valve or heavy spot on the wheel. If no balance pad is in the tyre, then align the tyre serial number to the valve or heavy spot on the wheel.
Be sure that wheel bolts are properly torqued per the wheel manufacturer’s maintenance manual.
Inflate tyre to rated pressure in a safety cage using dry nitrogen.
After 12 hours of stretch period, re-inflate the tyre to rated inflation pressure with dry nitrogen.