Maintenance-Free Accumulators Flying High

Cessna, now a division of Textron Aviation Inc., has been synonymous with private and corporate aircraft for generations. Cessna’s latest entry into luxurious corporate aircraft is the Citation Longitude, which holds up to 12 passengers and has a maximum range of 6,297 km, with maximum cruising speed of 882 km/hr. Featuring a wingspan of 67 ft. and length of just over 73 ft., the Longitude offers complete touchscreen control of navigation and communication systems with the next evolution of Garmin’s G5000 flight deck.

As with all aircraft this size and larger, the Longitude makes extensive use of hydraulics for controlling flight surfaces and many other functions. The hydraulic components and systems incorporate the most advanced technology available for compact design, light weight, and, of course, reliability.

Like many hydraulic systems, accumulators are needed for a variety of hydraulic functions, such as storing hydraulic energy and shock and vibration control. However, piston and bladder accumulators, which are widely used throughout the hydraulics industry, prove less than ideal for aircraft. That’s because piston seals must be replaced periodically and bladder accumulators come with their own set of limitations.

To circumvent these challenges, Textron Aviation specifies metal bellows accumulators from Senior Aerospace, Sharon, Mass., in the Cessna Citation. These proprietary, maintenance-free accumulators hold a gas charge within a hermetically sealed, welded-diaphragm metal bellows; no elastomeric seals are used. Thanks to proprietary gas-analysis software, Senior’s engineers were able to create an efficient design that met the Longitude’s specification requirements.

The Longitude represents Cessna’s first aircraft to incorporate all-metal bellows accumulators. The accumulators on the aircraft are used in the main hydraulic system; inboard, midboard, and outboard spoilers; emergency parking brake; and nose wheel steering.

Technicians responsible for maintaining the Longitude will have fewer components to routinely service because Senior’s maintenance-free accumulators are designed to last the life of the aircraft. The accumulators will never require recharging or seal replacement, as is common with conventional piston and bladder accumulators. 

For more information on Senior Aerospace’s welded-diaphragm metal-bellows accumulators, call (888) 235-5697, or visit www.metalbellows.com.