Attitude indicator has emergency battery backup

 - January 30, 2007, 10:38 AM

Mid-continent Instruments (, based in Wichita, has been marketing its 4300 series electric attitude indicator since the middle of last year. What makes the instrument notable is its lead-acid cell array battery backup, which provides up to 60 minutes of operating time in the event of an electrical failure in the aircraft. The 4300 is designed for either primary or standby attitude indication and can be connected to 14V or 28V systems. In the standby role, it provides double redundancy with its available battery power.

If electrical power is interrupted to the instrument, an amber annunciator light blinks to prompt the pilot to switch to battery power within 60 seconds. The system was purposely designed this way so the battery pack would not discharge if the aircraft master switch were inadvertently left on after landing. Internal emergency lighting is also available as an option. The battery automatically recharges from the aircraft electrical system.

The backup battery pack is designed to be replaced at three-year intervals or on condition (there is a battery-test function incorporated into the unit). Mean time between failure for the gyro itself is 7,500 hours and it’s certified to TSO-C4c. It installs with a single plug. A Mid-continent spokesman said the company has received inquiries from several Hawker operators about making a 2.5-inch version of the 4300 series. He said it could replace the IA804 standby gyro, which costs approximately $10,000–as much as $13,000 with a backup battery option.

Suggested retail price of the 4300 series with the battery pack is $4,450.