H-46 Sea Knight Helicopter Reaches Upgrade Milestone
PHILADELPHIA (October 19, 1998) - The H-46 Dynamic Component Upgrade (DCU) program achieved a milestone recently. The first set of DCU Rotor Heads successfully reached the 1,200 flight hour overhaul interval in September.
"The good news about the DCU program is how it has reduced fleet maintenance actions and eliminated periodic special inspections," said Pete Thompson, program manager at The Boeing Company in Philadelphia. "The data generated from the Age Exploration (Surveillance) program coupled with the laboratory component fatigue test results will serve as the basis for extending the time-between-overhaul interval for DCU rotor heads."
Initiated in 1992 to reduce unscheduled fleet maintenance actions and to eliminate recurring inspections, the DCU kit was designed, developed, tested and delivered within only three years, demonstrating the high priority it received for safety reasons. About 164 aircraft presently have the DCU rotor heads installed. Recent surveillance inspections revealed no surface corrosion or pitting at the 1,200-hour point, due to the use of a new steel in the rotor head dynamic components, 13-8 PH stainless steel, which is 20 times more corrosive resistant than the previously used material. This will effectively reduce the cost of H-46 ownership through the increased inspection interval, Thompson explained.
"The heads were flown by HC 6 in Norfolk, Va.," said Jon Winchester, Navy program manager for Fielded Programs at PMA-226, MCAS Cherry Point, N.C. "Aircraft that accumulated 1,200 hours in about 17 months were primarily performing the Navy vertical replenishment mission. Review of the maintenance record for that period indicated that the rotor heads required no unscheduled maintenance actions during that period."
The Sea Knight is the oldest type / model / series helicopter currently flying in front-line U.S. military service. Yet it remains capable and reliable thanks to modification programs, according to Thompson. The most recent of these programs is DCU. The Dynamic Component Upgrade Program replaces rotor head, flight control and drive system components with new components designed to improve corrosion resistance, increase wear protection and improve component damage tolerance. Recurring inspections and maneuvering limitations are eliminated. The DCU program provides 421 kits, including spares, for about 310 H-46s. The kits include transmission and flight control upgrades in addition to rotor head kits. Total program value is approximately $382 million.
Boeing also has developed larger fuel tanks that effectively double the mission radius of Marine Corps CH-46Es to up to 160 nautical miles. Other recent modification programs undertaken by the Naval Air Systems Command have made the cockpits of all Marine CH-46s compatible with night vision goggles, upgraded the avionics providing a communication and navigation control system, and equipped USMC and USN Sea Knights with provisions for emergency flotation systems. Boeing is currently involved in providing Utility Hydraulic System Upgrade Kits for all H-46s and is developing a new engine control system installation.
The H-46 Sea Knight has enjoyed nearly 35 years of Marine Corps service. From Vietnam to Desert Storm the "Frog" has been the Marine's front line medium-lift assault helicopter and will continue in service until replaced by the V-22 in 2015.
In addition to the Marine Corps' combat assault mission, the H-46 Sea Knight is used by the Navy and Marine Corps for search and rescue, and by the Navy for vertical replenishment at sea and for Special Warfare. Boeing delivered 624 H-46s to the Navy and the Marines from 1964 to 1971. Today the Marines operate 232 H-46Es and 9 H-46Ds. The Navy operates 69 H-46Ds.