Installation of NVIS aircraft lighting modification for a Sikorsky S-61 Helicopter. Night Vision Imaging System (NVIS) modifications are required to maximize visual acuity and safety while operating an aircraft with night vision goggles (NVGs).

ASU offers nearly 40 STCs covering more than 80 makes and models of rotary and fixed-wing aircraft. 

An alteration that will keep you running more efficiently for longer – reducing maintenance costs and increasing reliability. This modification replaces the original NiCad batteries found in the S-61 fleet. Unlike the original NiCad batteries, the new sealed lead acid batteries are not affected by thermal runaway. Therefore, the battery temperature warning system is disabled. This kit consists of two installations. The forward installation is in the forward avionics bay at the original battery location while the aft installation is in the original location for auxiliary battery. Each battery is a 24-volt, 42-ah RG-type valve regulated lead acid battery. The batteries provide power for limited ground operation and engine starting when external power is not available. The alternate battery is connected in parallel with the primary battery to the essential DC bus through a separate battery relay. This modification also removes the nose vibration absorber which is a common source of maintenance issues. This battery modification will make your S-61 safer, more reliable and reduce maintenance costs.

Reduction in fuselage length by fifty inches (from station 110 to station 160).