After more than 750 hours and 500 flights, the test team for the CH-46E Sea Knight helicopter recently completed its final mission as the helicopter, affectionately known as the Phrog, prepares for retirement in 2016.
The test team, based here at Naval Air Station Patuxent River, completed the final flight Oct. 9.
Part of Air Test and Evaluation Squadron (HX) 21, the “Mighty Battle Phrog” Test Team was established in 2008 to improve survivability and viability of the CH-46E. HX-21 covers the entire spectrum of ordnance-related operations, including weapons safe jettison separation, delivery and accuracy, night thermal imaging systems, helmet mounted night vision and head-up display systems, target sighting systems development, and stores jettison validation.
“The Phrog is the workhorse of the Marines and every pilot that has ever flown one has a special affection for the aircraft,” said Don Mueller, test team project officer. “To be able to extend the life of this aircraft, so that it could keep the Marines flying meant a lot to us. We all loved flying and working on this aircraft. We are going to miss it.”
Employed in every conflict since Vietnam, the CH-46E is a medium-lift, tandem-rotor cargo helicopter used by the Marine Corps to provide all-weather, day-or-night assault transport of combat troops, supplies and equipment.
The helicopter has seen several rebirths. Flight testing of the Sea Knight was thought to be complete in 1996, however, in February 2007 “urgent needs” from the fleet and changes to the MV-22B Osprey delivery schedule – the CH-46E’s replacement – pushed modifications and upgrades to the existing helicopters, delaying its retirement by a decade. Though targeted again for retirement in 2016, at least 16 Phrogs are being acquired by the U.S. State Department for diplomatic missions.
“The Phrog test team at HX-21 was an indispensable contributor to the enduring warfighting capability of the H-46,” said Marine Corps Lt. Col. David Walsh, the program manager for the Specialized and Proven Aircraft Program Office, which supports the CH-46E. “The team’s professionalism and fleet-focused approach benefited not just the H-46 community, but Marine aviation as a whole.”
Flight testing to improve survivability and to increase payload capability of the aircraft began in earnest in 2008, with initial efforts primarily benefitting the H-46 community. However, the team’s success and ability to quickly deliver results garnered the attention of other organizations, which leveraged its expertise.
The team supported test verifications for the MH-53 helicopter, provided operational test support to Naval Sea Systems Command for its new ship-borne chemical and biological sensor system and participated in two Marine Aviation and Tactics Squadron exercises.  The group was also tapped to provide supplementary fleet squadron training and to improve the H-46 trainer.
Other projects completed by the team included evaluation of three separate missile countermeasures systems, aircraft health monitoring, high-frequency radio upgrades and wireless and replacement intercommunication systems. The wide range of tests benefited not only the CH-46E community, but the H-53, V-22, H-60 and H-47 communities as well, Mueller said.
“Of all of the aircraft in today’s Navy/Marine [Corps] fleet, the Phrog has the lowest maintenance man hour and cost-per-flight hour,” Mueller said. “To be able to meet the many emergent requirements the flight test team was faced with, we had to quickly plan, test and get the results back to the fleet. We were able to accomplish this because our test team consisted of a small group of maintainers and engineers who were dedicated to the aircraft.”

NAVAIR press release