PRECISION BEARINGS AND SPECIALISED TOOLS MEET THE DEMANDS OF TODAY’S LANDING GEAR TECHNOLOGY

When we hear the familiar request from the flight deck ‘Cabin crew…prepare for landing’ we know its part of the preparation for the arrival of a passenger plane to its destination and one of the critical stages of any flight. What goes up…must come down (safely and smoothly) and perhaps something we take for granted is the performance and reliability of today’s aviation landing gear technology.

Regarded by some aviation experts as ‘mechanical marvels,’ landing gear is literally a ‘big deal’ in terms of size and cost. For example, it’s estimated by the world’s leading airline manufacturers to represent around 20% of total aircraft maintenance and around 7% of the total weight of the aircraft. For example the maximum take-off weight of an Airbus A320 (one of the today’s biggest selling aircraft with over 16,000 flying) is approx. 83,000 kg (183,000 lb) of which around 5500 kg (12125 lb) is the weight of the landing gear.  

Typically landing gear is made by speciality suppliers to the aviation industry who then supply to the major manufacturers, mainly because landing gear and shock absorption is regarded as a field of science on its own compared to other parts of aviation technology.

A key component of modern landing gear systems are specialist bearings with the common applications being landing gear struts and actuators. Precision bearing specialists CARTER MANUFACTURING are approved aerospace bearing suppliers to industry leading landing gear manufacturers and are accredited to ISO9001 incorporating the requirements of AS9120 with flow down from AS9100. Where required their bearings include AS9120 Aerospace First Article inspection reports for traceability of all raw materials and special processes along with full dimensional analysis.

One of the main issues with landing gear components, either when installing or maintaining, is their size and the risks associated when moving them to different departments.

Special, customised aerospace portable bearing tools are available from Carter to alleviate the pressures, such as clearance restrictions including anti-rotation features which have been proven over decades of experience from thousands of successful projects. Using a portable set of tooling can allow for the safe removal, installation and testing of the bearings without having to move the component.

In most landing gear systems the bearings are usually situated at the end of a very long and heavy tube with limited access which means special fixtures need to be designed to ensure the component is square and secure to the hydraulic press, or vertical milling machine. This issue can be overcome by using the portable tools. For example, a staking force for a 4” OD bearing would be around 50,000 lbs, while the swaging force for portable tools is so low it can be simply applied by hand with a wrench.

Carter’s swaging tools are precision engineered to suit specific landing gear bearings helping to reduce operational risks and reduce costs by minimising the possibility of damaging expensive bearings and housings. If the customer doesn’t want to use portable tools (or the application dictates a different approach), drill press style swaging tools are another option providing a better option than anvil staking tools because the swaging force required is a fraction of the overall staking force and will drastically improve the quality of the swage.   

Carter also supports projects using their proprietary bearing application software to validate theoretical bearing performance and they can also provide detailed reports which better educate customers and validate mission critical decisions.

More at:  https://www.carterbearings.co.uk/bearings/custom-aerospace-bearings    ENDS.