MARINE CORPS AIR STATION MIRAMAR, Calif. -- It is an aircraft with more than four decades of service in the Marine Corps.

With protruding side wheels and a nose-up attitude on the ground, the CH-46 Sea Knight helicopter has the appearance of a frog ready to hop - some would say it certainly does, especially when moving forward on the deck.

Since the Vietnam era, the "Phrog" as it is affectionately known, can best be described as a flying bus. Lifting troops and cargo to and from the front lines, it can carry up to 25 combat-ready Marines while remaining airborne for more than two hours on internal fuel tanks.

"The current CH-46E is a very resilient, combat-proven aircraft," said 1st Lt. David C. Nicol, pilot, Marine Medium Helicopter Squadron 165, Marine Aircraft Group 16, 3rd Marine Aircraft Wing. "It has some unique features that distinguish it from other helicopters, but it is best known for its ability to provide assault support and medium-lift requirements. What has made it so useful is it's high maneuverability being able to quickly drop off Marines and equipment into combat zones more easily than other aircraft."

Distinctive in appearance, the tandem-rotor, twin-piloted Sea Knight has six rotor blades, each measuring more than 25-feet long. With the blades fully spread, the 16-foot, 8-inch tall aircraft is more than 84 feet long. Its twin-turbine General Electric engines can propel the aircraft in excess of 160 miles per hour to a ceiling of 10,000 feet with a maximum take-off weight of more than 24,000 pounds. In combat, it carries a crew of five: a pilot, co-pilot, crew chief and two aerial gunners each manning an M2 .50 caliber machine gun mounted to either side.

Performing combat logistical support, casualty evacuation, search and rescue, as well as special operations missions for the Marine Corps, the CH-46E allows for increased agility and handling qualities in strong relative winds from all directions, according to www.boeing.com/rotorcraft/military/ch46e.

The CH-46E has served in all combat and peacetime environments, and can be found just about everywhere the Marine Corps flies, from the stable shores of the United States across the open seas to the more unforgiving climates of Asia and Africa.

Although generally regarded as reliable, the Marine Corps has been looking to replace the aging CH-46E with a faster, longer range and greater carrying capacity airframe.

"The original airframe is old, but everything else on the aircraft is new since over time, safety and capability upgrades have continued to allow safe and effective operations until the "Phrog" is eventually replaced by a new aircraft such as the Osprey," said Nicol.

The MV-22 Osprey, a helicopter fixed-wing hybrid with a tilt-rotor design of the Bell-Boeing team, has been selected as that replacement and is slated to begin operational testing in Bern, N.C., according to a recent Boeing press release.

In the wake of such developments, Marine "Phrog" pilots are already looking to the future.
"Some 46 squadrons are preparing to stand down in anticipation of switching over," said Nicol . "The CH-46 is a great combat-proven aircraft, but we're open to progress with the prospect of the Osprey."

For the Marine Corps, the operational testing is an important first step in the development of a long-term commitment to MV-22. Marine Tilt-rotor Test and Evaluation Squadron 22, the first MV-22 test and operational squadron, recently passed the Osprey with "flying colors" after completing their operational evaluation July 13.

While the days of the Marine Corps' CH-46E may at last be numbered with the advent of a faster, longer-range aircraft designed for the 21st century battlefield, it nonetheless continues to serve faithfully for the Marines.