Sandel Avionics has introduced vibration-resistant versions of its SA4550 primary altitude and SN4500 primary navigation displays for helicopter applications. The company is offering the displays for retrofit to replace aging electromechanical ADIs and HSIs. The 4-ATI units have the option to be night-vision goggle compatible for both military and commercial applications. Sandel’s patented rear-projection display technology with LED-backlighting is used in both the SA4550 and SN4500, providing 180-deg. viewing angle, bright color renditions and an MTBF of over 10,000 hr, the company says. The vibration-resistant versions of the SA4550 and SN4500 are tested to meet the demanding DO-160E helicopter vibration standard. The SA4550 and SN4500 operate independently of each other and an operator can choose to install the units singly or together as a package.