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Tuesday, May 1, 2012

From Avionics Magazine: Snake Pit Superior

An AH-1Z Cobra with the Aviation Combat Element of the 11th Marine Expeditionary Unit hovers above the USS Makin Island in the first shipboard deployment of the attack helicopter. Photo courtesy U.S. Marine Corps

Editor’s Note: The following excerpt from “Snake Pit Superior” by Frank Colucci originally appeared in the April 2012 issue of Rotor & Wing sister publication, Avionics Magazine. A link to the full text can be found at the bottom of the page.

Aboard the amphibious assault ship Makin Island, the Bell AH-1Z completes the U.S. Marine Corps H-1 helicopter upgrade and gives the 11th Marine Expeditionary Unit a truly integrated light attack helicopter element. The four AH-1Z attack and three UH-1Y utility helicopters in their first combined sea deployment share avionics, dynamics, engines and structures to reduce supply, maintenance and training burdens. Just as important, the Northrop Grumman Integrated Avionics System (IAS) in both aircraft reduces crew workload and increases situational awareness with common hardware and software. The improvements are game-changers, especially in the tandem-seat attack helicopter that long kept pilots in the back with reduced visibility and co-pilot/gunners up front with reduced functionality.

According to H-1 program manager Marine Col. Harry J. Hewson at the Naval Air Systems Command, “We’re finding in the AH-1Z there’s a role reversal. The front-seat pilot is doing all the flying. The rear-seat pilot is working the weapons.”

Identical front and rear cockpits in the Zulu Cobra are built around color multifunction displays (MFDs) with flight symbology, moving map, communications, weapons management and subsystems pages. Sidesticks with Hands-On-Collective-and-Stick (HOCAS) controls call up display pages and reduce pilot hand and eye movements for weapons selection, flare and chaff dispensing, radio frequency selection, and other functions. Hand-held mission grips enable either pilot to control the multi-sensor Target Sight System (TSS). Optimized Top Owl helmets show pilots targeting, navigation, and flight symbology, and slave the TSS to the user’s line-of-sight. One Marine pilot in the Zulu systems working group compared the legacy AH-1W SuperCobra to the new AH-1Z: “It’s like going from a VW Beetle to a new Lexus.” Current plans remanufacture 131 AH-1Ws into Zulu Cobras and build 58 new AH-1Zs through 2019.

Marine Cobras have evolved from the 9,500-lb AH-1G first delivered in February 1969 to the 18,500-lb AH-1Z declared operational in February 2011. The fourth-generation AH-1W introduced in 1986 today watches over Marines in Afghanistan with an Elbit-Kollsman night targeting system and Hellfire and TOW missiles. Piecemeal developments nevertheless gave the Whiskey Cobra a high-workload cockpit. “There were some fairly significant shortcomings in the AH-1W,” acknowledged Hewson. “The AH-1W was very much a federated cockpit. It had a lot of systems scabbed-on that did not interact with other systems on the aircraft. It was up to the pilot to turn things on and move things around.”

By one count, an AH-1W front-seater needed 52 switch actions to arm, select, program and launch a Hellfire missile. Different front and back cockpits complicated crew coordination. The Whiskey Cobra back-seater could fire weapons but could not program Hellfire laser frequencies or use the original day-only weapons sight. While the back-seater had no long-range visionics, the front-seater no head-up display (HUD) to aim rockets. Either pilot in the Whiskey Cobra could use an antiquated mechanical helmet tracker to aim the Cobra gun, but one crew member had to be talked-on to targets spotted by the other.

Even with the Mil-Std-1553B databus on the AH-1W, the rudimentary fire control system could not use data generated elsewhere on the helicopter. “Information exchange between the navigation system and the fire control was limited,” observed Hewson.

Aircraft survivability suite likewise bridged stand-alone subsystems. With an APR-39 radar warning receiver display only in the aft cockpit, the front-seater who heard a warning had to ask the pilot for threat location.

For the full version of this story, please visit www.aviationtoday.com/av

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