Test Team Pushes, Expands H-1 Envelope

The Air Test and Evaluation Squadron (HX) 21 conducts flight envelope testing of the UH-1Y Venom aboard USS Mesa Verde (LPD 19). (U.S. Navy photo)


Flight test at sea occurs often, but while embedded in a forward deployed unit? That’s taking flight test to a completely different level.

Atest team from Air Test and Evaluation Squadron (HX) 21 reached that level in May as they met the challenge of conducting testing required to expand the flight envelope for the UH-1Y Venom helicopter onboard San Antonio-class amphibious landing dock ship USS Mesa Verde (LPD 19).

“It all got started when a deployed fleet pilot, Maj. ‘Rudy’ Neagle, reached out directly to the HX-21 pilots asking if they could help expand the UH-1Y wind envelope,” said Kristen Finnegan, the test team’s lead engineer.

The flight envelope refers to the conditions in which an aircraft can safely operate. The UH-1Y helicopters had been operating within the restrictive generic wind envelope for six-to-seven years.

As Neagle—the aviation combat element LPD detachment officer-in-charge (OIC) from Marine Medium Tiltrotor Squadron (VMM) 365 (Reinforced), 24th Marine Expeditionary Unit (MEU)—began researching the limited flight envelope, he was looking for the lessons learned from other pilots who had faced similar challenges.

“It had not occurred to me to conduct testing on Mesa Verde while deployed,” he said. “I was looking for information to mitigate risk while flying outside the wind envelope.”

According to Neagle, during the first two months of deployment aboard Mesa Verde, about half the night sorties had to be canceled due to wind. In one instance, during the first week of May, a scheduled vertical replenishment (VERTREP) between Mesa Verde and a replenishment-at-sea (RAS) ship was canceled because of high winds outside the UH-1Y’s flight envelope.

“We launched the UH-1Y, and then the two ships came alongside, connected all their guidelines and fuel hoses,” but had to break away in order to recover the helicopter once the wind picked up, Neagle said. The RAS was ultimately completed without the VERTREP.

This and similar occurrences caused Neagle to begin his quest to increase the wind limits. As they looked at flight schedules, it became apparent that UH-1Y flights were frequently on the edge of the wind envelope and canceled as a result.

Neagle said they used the canceled VERTREP to highlight the wind problem and get the ship’s leadership behind fixing it.

Neagle reached out to other H-1 detachment OICs to see how they had tackled the wind problem. His initial research led him to contact HX-21, which developed a test plan and received approval from the H-1 program office to proceed.

“This was the first time I had performed flight test with a deployed unit,” said Marine Corps Maj. J.M. Kennedy, an HX-21 project officer and developmental test pilot. “It was a very unique and dynamic environment.”

The operational environment required the members of the test team to be more flexible and to have a fluid schedule.

“We needed to integrate with the missions assigned to VMM-365,” Kennedy said.

For Eric Becker, a test engineer with HX-21, the opportunity to test and live alongside the end user brought the job into focus.

“It was a great opportunity to see how our work impacts the fleet and how it translates directly into their ability to meet the mission,” he said. “While we were testing, the operational guys were fielding communications about real-world operations happening close enough that it wasn’t even over the horizon. These are the people we work for. And that is a pretty good feeling.”

The test team wasted no time in analyzing their data upon returning to Naval Air Station Patuxent River, Maryland. Within nine days, it had completed a data review of more than 20 hours of flight test data and released an Interim Flight Clearance allowing the UH-1Y to operate in a newly defined wind envelope aboard San Antonio-class LPDs.

“The expanded envelope benefits both the Navy and the Marines in the fleet,” Neagle said. “It benefits the Navy due to the increased flexibility in driving the ship during flight operations. They have more room to maneuver with a larger wind envelope. It benefits the Marines because HX-21 has tested the performance of the aircraft at greater wind envelopes on each spot, providing assurance to the aircrew of the UH-1Y’s performance in those conditions.

“There were many people that had to jump through hoops to turn this event around as quickly as they did. This was a team event between the Mesa Verde, 24th MEU ACE and HX-21. The credit really goes to the HX-21 team that was able to pull off all the test plan approvals and get to the ship before it left port.”

Written by Program Executive Office Air ASW, Assault & Special Mission Programs Public Affairs

The test team from Air Test and Evaluation Squadron (HX) 21 conducted flight envelope expansion testing onboard USS Mesa Verde (LPD 19) this summer. From left are Maj. Joe Kennedy, project pilot; Josh Marvin, lead dynamic interface engineer; Staff Sgt. Forest Pike, crew chief; Kristen Finnegan, lead dynamic interface engineer; Maj. Don Underwood, project pilot; Maj. Camille Lampert, project pilot; Amanda Wirz, test engineer; Erick Becker, test engineer; Justin Marut, test engineer; and Maj. Patrick Flores, dynamic interface project officer and detachment officer in charge. (U.S. Navy photo)