Photo: A CH-53D Sea Stallion lands aboard USS Boxer (LHD 4) during tests to expand the aircraft's wind envelope. The tests were highly successful, with the wind envelope expanded to double the original specifications. Photo by Kurt Long.
The Marines’ older heavy lifter, the nearly 30-year old CH-53D Sea Stallion, recently had its capabilities expanded to operate from the Navy’s newest class of multi-purpose amphibious assault ships.
Test pilots, enlisted crew and flight test engineers from NAVAIR flew to Hawai’i and California and performed wind envelope tests on the Okinawa, Japan-based helicopters, where the lack of wind envelope data imposed severe restrictions on how the aircraft could be used aboard LHD-class ships.
With wind conditions just right, three Marine test pilots put the Sea Stallions through their paces and expanded the wind envelopes for the aircraft aboard LHD class ships—more than doubling the existing envelope and achieving an instant impact.
“The fleet was immediately able to use the information we provided,” said Marine Maj. Rich Marigliano, one of the test pilots. “The day the information was received, the same day they were able to launch a mission they would not have been able to launch before. Those ‘53Ds would not have been able to launch without this test.”
The tests were carried out in early September aboard USS Boxer (LHD-4) and were done with support from Marine Aircraft Group 24. The opportunity for the test arose when Boxer was tasked with transporting Sea Stallions from Hawaii to California for pre-deployment exercises.
Over the course of six days, Marigliano, Marine Maj. Hank Vanderborght and Marine Sgt. Tom Dungan, with support from Marine Cpl. John Carnley of HMH-363, flew 29 hours and conducted 129 shipboard takeoffs and landings. Half of the testing took place under nighttime conditions, with 65 percent of that time spent in low light level conditions.
The daytime flight envelope was more than doubled, while the nighttime envelope with night vision aided flight was significantly increased as well. The envelope is now one of the most flexible aboard LHD’s with wind speeds of up to 45 knots off the bow.
“The engineers were extremely excited, they have never seen a test get as much data or progress as much in one test period,” Marigliano said. “We got more data in one day than most tests get in a weeks time.”
He attributed the wealth of data to the wind conditions prevalent during the testing.
“The winds were remarkably strong and conducive to these tests,” Marigliano added.
Based on an airframe dating back to the early 1960s, the CH-53D was never tested for suitability aboard the LHD class ship because it was not anticipated that the aircraft would still be in service when the LHDs were rolled out.
Although now classed as a medium lift platform, the ruggedness, versatility and capability of the aircraft keeps it in service alongside its replacement, the CH-53E Super Stallion.
Vanderborght said the Super Stallions are heavily used around the world which is placing a strain on the fleet . Because the Sea Stallions are able to handle so many of the same missions, it seemed like a good fit to make them available to take on some of that load.
“We need to have the CH-53D helping out with the global war on terrorism,” Vanderborght said.
Marigliano added that when the CH-53Ds are put into action it will not only give the CH-53Es relief, but will also free them up for deployment to other areas where they are needed.
Vanderborght said that the test team’s mission was to find exactly where the limits were for the CH-53D and how the aircraft can most effectively be deployed within those limits.
“A couple of times, we found those limits,” he said.
To perform the test, the aircraft would start in a particular spot within the general wind envelope, and from there it would be pushed to the edges and beyond to see how far it could go.
The first four days of testing were performed near Hawaii in high wind conditions, while the last two days took place off the coast of California in lower winds, allowing the test team to discover how the aircraft handles under a variety of weather conditions.
“It was really exciting for us, this is the kind of testing we anticipated doing when we were going through Test Pilot School,” Marigliano said.
-Story by Bryan Jaffe