NAVAIR helps Coast Guard arm helos for new mission
US Naval Air systems Command (NAVAIR), March 19, 2003 - PATUXENT RIVER NAVAL AIR STATION, MD By Karen L. Jensen, Naval Aviation Science & Technology Office — The smallest of America’s armed services, the Coast Guard has found its role in national security stepped up in the last two years. With NAVAIR help, it is preparing for heavier homeland security responsibilities.
The key to expanding the Coast Guard’s role in maritime law enforcement is the arming of its inventory of HH-65 Dolphin and HH-60 Jayhawk helicopters. The first step in this process was certification of both airframes for the M240D machine gun.
This is where the NAVAIR partnership kicked in. Lt. Cmdr. Lorinda Couch, HH-65 system manager at U.S. Coast Guard Headquarters, contacted Bob Blevins, NAVAIR’s Coast Guard project coordinator, about designing, installing and testing gun mounts for their helicopters.
“The Navy is the expert in this area,” said Couch, “and NAVAIR had helped us before.”
Because Blevins had spent most of his career working in the NAVAIR rotary-wing community, he had seen many gun mounts installed on Navy helicopters. He knew that the work could easily be done at Patuxent River, with some help from the Naval Surface Warfare Center Crane, Ind.
A team of mechanical engineers at Crane agreed to design a gun mount specifically for the Coast Guard’s needs. Nick Patregnani, from NAVAIR’s Air Vehicle/Store Compatibility Division, signed on as the lead test engineer, and the project began. M240 machine gun mounts were designed and installed on an HH-65B Dolphin and an HH-60J Jayhawk.
NAVAIR aircraft instrumentation experts installed a laser sighting camera to test the design of the mount and stops. As the gun was aimed at the forward, backward, up, and down stops, the camera pinpointed how close the gun projectiles were to the nearest part of the helicopter.
“You want to give the gun as much freedom to shoot as you can,” said Blevins, “but you also want to ensure that there is a safe distance between the gun and the closest point it can come to the auxiliary tank, tail, feathers, blades, and even the pilot.”
Shooting camera pictures with the laser sighting allowed the testers to follow the laser beam and determine the amount of clearance required between the gun and other objects in the aircraft.
The firing tunnel here was used for a dry run of the entire gun system before taking to the air. This phase of the project was a safety buildup to flight testing. The gun was fired down the tunnel to monitor the loads being transmitted into the aircraft, measure vibration levels, and ensure that bullet scatter was within an acceptable range.
“If there are any severe structural problems or defects, they will typically show up in the firing tunnel,” said Patregnani. “This is a good way to uncover any unexpected problems, things that you may not have thought of.”
In addition to checking loads and bullet scatter, it provided the end users of the gun an opportunity to get “trigger time” and gain familiarity with the system before they flew with it.
“One unique aspect of this testing,” Patregnani said, “was that the HH-65 is a commercial aircraft, so it was not built for arming. There was never the intent for that until now. It presented an interesting challenge for us.”
Work on the HH-60J was less complicated because mount positions and other data from the Navy HH-60H, an identical airframe, were already available. Navy and Coast Guard pilots and gunners worked side-by-side during all aspects of the ground and flight tests.
“We work with the Coast Guard personnel until they are autonomous,” said Blevins. “We help them get the right equipment and then train them on how to mount the gun and operate it. At that point, we back out of the picture.”
NAVAIR testing on the HH-60J and the HH-65B, including ground fit checks, ground test firing, captive-carriage-of-fire check flights, and live-fire flight tests, were successfully completed in mid-February. NAVAIR is also adding a flashing blue police-type light and white night-lighting on the aircraft to illuminate the Coast Guard logo.
As many as 170 Coast Guard helicopters could receive the gun mounts, which will be a significant step toward enhancing drug interdiction and port security operations.
Blevins emphasized that the Navy, as the Coast Guard’s sister agency, will help wherever it can with the Deepwater program, which is a major overhaul of Coast Guard assets. The gun mount test is but one example of how the Navy and Coast Guard are collaborating to achieve a national fleet concept for the United States. Future work includes parallel flight certification testing of the C-130J for the Marine Corps and the Coast Guard. Blevins also expects to coordinate Coast Guard usage of the electromagnetic environmental effects, infrared identification, and range facilities at NAVAIR in the near future.
“I feel that I’m helping the Coast Guard do their job more efficiently,” said Blevins. “The Coast Guard gets the benefit of the product, and we can all sleep better at night.”
Aerospatiale HH-65 Dolphin 6542 ( US Coast Guard )
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Aerospatiale HH-65 Dolphin in US Coast Guard
Sikorsky S-70 H-60 in US Coast Guard
NAS Patuxent River