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AH-1Z Viper

A four bladed version of the AH-1W was designated the AH-1Z. The addition of the extra blades dramatically improves the performance envelope of the AH-1W. The AH-1W was also to be retrofitted with a Kollsman-manufactured Night Targeting System (NTS). The aircraft was also undergoing a cockpit reconfiguration to allow for easier copilot/gunner access to the NTS. The upgrade of the AH-1W, including the new cockpit, was initially referred to as the Four Bladed AH-1W (4BW) and the upgrade of the UH-1N drive train was initially referred to as the Four Bladed UH-1N (4BN). Collectively, the 4BN/4BW effort constituted the USMC H-1 Upgrades Program.

The Marine Corps planned to upgrade 180 of the AH-1W gunships to the new AH-1Z standard (formerly referred to as AH-1W (4BW)). The first flight was conducted in December 2000, with planned low-rate initial production beginning in February 2002, and deliveries planned to run from 2004 through 2013.

In July 1998, Bell Helicopter competitively selected Lockheed Martin for development of the AH-1Z Target Sight System (TSS). The TSS would provide advanced third generation thermal image processing, eye-safe laser range finding, target designation, and full fire control integration. In August 1998, four AH-1Ws were delivered to Bell Helicopter for conversion into AH-1Z test aircraft. In September 1998, engineers completed a highly successful critical design review of the airframe, which featured a state-of-the-art, computer generated electronic mock-up to convey design details. The design review paved the way for manufacturing development. Also in 1998, the program delivered seven AH-1Ws to the Marine Corps, bringing the aircraft inventory to 201. Additionally, several other improvements for the AH-1W (night targeting system and communications/navigation) continued.

The H-1 upgrade program combined upgrades of two USMC H-1 aircraft: the AH-1W Cobra attack helicopter and the UH-1N light utility helicopter. The common element of the two would be identical twin engines and drive trains, including a new four-bladed rotor previously developed but not fielded. In addition, the AH-1 attack helicopter would gain a new integrated cockpit and night targeting system. The upgrade was intended and expected to extend the life of the two H-1 models well into the 21st century. The AH-1 would contribute to precision engagement and full-dimensional protection.

Bearingless, composite main rotor systems were successfully tested at BHTI in the early 1980's and were standard on the Bell 430 helicopter. Based on the performance of this rotor system, the USMC decided to incorporate it in their new AH-1Z helicopter. This unique rotor system was stated by the manufacturer to provide unprecedented agility, substantially increased speed, a smoother ride, a more stable weapons platform, and excellent reliability. It would also reduce crew fatigue and enhance combat mission effectiveness.

A Sikorsky Bearingless Main Rotor (SBMR) was successfully tested in the 40- by 80-Foot Wind Tunnel test section of the NASA Ames National Full-Scale Aerodynamics Complex (NFAC). The five-bladed 44-foot diameter demonstrator rotor system was designed using existing S-76 composite main rotor blades and a new five-bladed hub, employing design features similar to the rotor proposed for the subsequently canceled RAH-66 Comanche. The rotor was first tested on the Sikorsky Main Rotor Whirl Stand, concluding in August 1991. A Memorandum of Agreement (MOA) was then signed to perform a wind tunnel test at Ames. Under the MOA, Sikorsky performed additional qualification testing and analysis to support the test program. NASA provided technical support during the pre-test effort and then tested the rotor system for a 14-week period during the summer of 1992.

Under the initial 4BW/4BN upgrade plan, fully integrated cockpits would be phased into the development after initial work on the drive system was underway. Initial work would consist of simultaneous design efforts for the 4BW and 4BN. Major modifications would include: a new rotor system with semi-automatic bladefold of the new composite rotor system, a new performance matched transmission, a new 4-bladed tail rotor and drive system, a more effective stabilizer, upgraded landing gear, tail pylon structural modifications and common cockpits.

The remanufacture was expected to add 10,000 flight hours to 4BW/4BN airframes. The 4BW would increase aircraft maneuverability, speed, and payload (ordnance) capability. The fully integrated cockpits would reduce operator workload and improve situational awareness, thus increasing safety. It would provide growth potential for future weapon systems and avionics, which would increase mission effectiveness and survivability. As discrete systems had previously been added to both aircraft, pilot workload had progressively worsened. The cockpits would include integration of on-board mission planning, communications, digital fire control, self navigation, night targeting, and weapons systems in nearly identical crew stations reducing training requirements.

The 4BN/4BW program was instituted in the summer of 1996 by combining several lesser upgrades planned, but not executed by the Marine Corps. Prior to entry into EMD in September, 1996, DOT&E approved the program's alternative LFT&E plan and USD(A&T) approved a waiver from full-up, system-level LFT&E. The AH-1W would be tested full-up, system-level. The H-1 Upgrade ORDs required that both helicopters (the upgraded AH-1W and UH-1N) be tolerant to impacts by 12.7mm rounds and have crashworthy enhancements. Additionally, the drive components of the AH-1W were to be tolerant to 23mm rounds.

The H-1 Upgrade had the most comprehensive and realistic aircraft LFT&E program approved to date. The program would include full-up, system-level testing of an AH-1W and testing of all but the tail (which is common to both aircraft) of the UH-1N. It would explore in detail various potential kill mechanisms related to the expected threat. The LFT&E program was integrated fully into the systems engineering effort and was expected yield a reasonable opportunity to incorporate improvements if deficiencies were found.

Accoridng to DOT&E, the AH-1Z attack helicopter demonstrated a doubling in payload and a 20 percent increase in range and endurance over the AH-1W aircraft during 2003 testing. The digital cockpit enhanced pilot situational awareness and reduced workload in some areas. However, poor targeting performance of the newly installed Targeting Sight System (TSS) degraded mission effectiveness and increased pilot workload. Problems with TSS stability, focusing, target loss during field-of-view changes, and anomalous TSS behavior must be resolved before this aircraft can be considered operationally effective.

A decision had been made to produce the UH-1Y portion of the program as new aircraft, rather than as conversions from existing UH-1Ns. Program officials were studying the feasibility and cost of also building the AH-1Z's new. A date for that decision had yet to be determined as of mid-2005.

In May 2006, the Navy initiated the program's fourth major restructuring effort, resulting in an approximate 18-month delay in the full-rate production decision (expected for July 2008 as of March of that year), a reduction in production quantities from 47 to 38 (UH-1Y and AH-1Z) in FY06 to FY08, and the extension of low-rate production. At the same time, the contractor had failed to meet the commitments of an increased production rate. Program officials stated that the prime contractor's delivery schedule was a key risk that could affect the UH-1Y initial operational capability. The prime contractor had experienced challenges with supply chain management, manufacturing standards, and built-in quality, affecting program schedule and resulting in aggressive training timelines with little margin. If the planned September 2008 initial operational capability was not met, the program may face an acquisition program baseline breach and risk undergoing a fifth restructuring. Additionally, the contractor's earned value management system was decertified. The program expected recertification during spring 2008.

The program office reported to the Government Accountability Office for a March 2008 assessment that it had all 2,611 AH-1Z drawings, a measure of design stability. The program did not track data for critical process control in manufacturing, but utilized postproduction quality metrics. The H-1 upgrades program was approved for Low-Rate Initial Production Lot 4 in July 2007 and currently had 34 aircraft on contract (UH-1Y and AH-1Z). The program reported that three AH-1Z had been delivered to date. Program officials reported that the third AH-1Z and fifth UH-1Y were delivered in October and November 2007, respectively. The program was undergoing its fourth major restructuring, which had delayed the expected full-rate production decision by 18 months, then expected for July 2008.

An operational test report identified performance issues with key technologies that would need to be resolved prior to initial operational capability. For example, the program's target sight system continued to experience a high failure rate, which could affect the AH-1Z's readiness for fielding. Further, flight restrictions were in effect for both the AH-1Z and UH-1Y during operational test and evaluation due to the poor performance of the helmet-mounted sight displays (HMSD), a key weapon system upgrade. The visual sharpness of the HMSD did not support shipboard landings at night, depth perception cues were misleading, and HMSD components were not reliable. The program reported designed improvements were being tested to address these challenges.

The program office was using FY07 funding for preliminary engineering for new AH-1Z airframes. The program had experienced significant delays and cost growth in the manufacturing of initial production aircraft, leading to 140 percent cost growth and 36 percent schedule growth by the time of the 2008 GAO assessment. The cost growth experienced by the program was due primarily to revised estimates for labor, material, and tooling based on manufacturing performance data from development and initial production aircraft. The program reported that requirements changes in previous years had also contributed to cost growth.


Turkish Government officials announced on 21 July 2000 that the Bell Helicopter Textron KingCobra had been selected as the winner to fulfill its attack helicopter requirements. Bell would subsequently enter into negotiations as to specifics of the program and applicable agreements. The KingCobra was the Turkish variant of the AH-1Z being developed for the US Marine Corps. Along with wheeled gear, the KingCobra incorporated significant mission equipment to be provided by Turkish defense industries.

The newest version of the Cobra Attack Helicopter was equipped with state- of-the-art avionics, power train and weapons systems. This combination of modern technology and Bell Helicopter reliability and ruggedness was said by the manufacturer to make this third generation Cobra the most cost effective and modern attack helicopter available in the world at the time.

The initial Turkish requirement called for 50 aircraft at a cost of approximately $1.5 billion (US) with a possible build-up to 145 aircraft. Bell Helicopter Textron would be the primary sub-contractor on the program with Tusas Aerospace Industries Inc. of Ankara, Turkey acting as prime contractor. Additionally, there wiykd be numerous other sub-contractors that will provide the armament, avionics and engines.

On 2 June 2000 Turkish Prime Minister Bulent Ecevit said that Turkey had postponed a decision on a massive $4.5 billion tender to build 145 strike helicopters.

Prior to the Executive Committee's decision dated May 2004, Tusas Uzay ve Havacilik San. AS was selected as prime contractor. In order to determine foreign company, proposals from Agusta (Italy), Bell (USA), Boeing (USA), Eurocopter (France) and Kamov (Russian Federation) were received. Contract negotiations with two companies in the short list, Bell and Kamov, were executed. The last status of the project was discussed at the Executive Committee's meeting dated 14 May 2004, and it was evaluated that the proposals of subject firms did not meet the expectations related to price, delivery schedule, contracts terms and conditions for technical & administrative issues. Based on this, bid was been cancelled and it was decided to accept a new bid for a new project model. SSM had begun to make preparations on the new project model which aims also to meet requirements in a shorter period and to use in-country capabilities and use its best effort to publish Request for Proposal (RFP) as soon as possible.

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Page last modified: 07-07-2011 02:26:49 ZULU