N635CK

N635CK is a Sikorsky S-61R operated by CROMAN CORP. SkyMeter has tracked 44 flights totalling 161 hours of airtime via ADS-B. Service window in our records spans 359 days. The Sikorsky S-61R has a maximum takeoff weight of 22,050 lb, medium wake category.

About the Sikorsky S-61R

The Sikorsky S-61R is a twin-turbine heavy-lift helicopter that emerged in the 1960s as a civilian derivative of the legendary HH-3 Jolly Green Giant, itself a stretched and modified version of the S-61 Sea King. While the military HH-3 became famous for combat search-and-rescue missions in Vietnam and dramatic Apollo astronaut recoveries, the commercial S-61R found its niche in demanding utility roles where its combination of power, payload capacity, and rear loading ramp proved invaluable. Powered by two General Electric T58 turboshaft engines producing 1,500 shaft horsepower each, the S-61R can lift external loads exceeding 8,000 pounds and operate effectively in challenging environments from offshore oil platforms to remote logging sites.

What distinguishes the S-61R from its naval sibling is the boat hull deletion in favor of tricycle landing gear and a hydraulically operated rear ramp, transforming it into a true aerial truck capable of loading vehicles, cargo pallets, and oversized equipment. The type's robust construction and redundant systems made it a workhorse for operators requiring heavy-lift capability without the operating costs of larger helicopters like the S-64 Skycrane. Maximum cruise speed reaches approximately 140 knots with a never-exceed speed of 138 knots, and the type can maintain a hover out of ground effect at weights up to 19,000 pounds under standard conditions.

Today the S-61R remains in limited commercial service, primarily with specialized operators performing firefighting, heavy-lift construction support, and utility missions where its unique combination of cabin volume, external lift capacity, and rear-loading capability still offers advantages over more modern designs. The type's rugged reliability and proven track record in extreme conditions have given it remarkable longevity, with some airframes accumulating over 20,000 flight hours across five decades of operation. SkyMeter has tracked flights across airframes and operators, with the largest observed operator.