OH-58D Kiowa Warrior
The OH-58D Kiowa Warrior is a two-seat, single-engine, four-bladed single main rotor light helicopter with a low light television, thermal imaging system, and laser range finder/designator incorporated into an above the rotor Mast Mounted Sight (MMS). It is designed to operate autonomously at standoff ranges providing armed reconnaissance, command and control, and target acquisition and designation under day/night, hot, and adverse weather conditions. The Kiowa Warrior can designate targets for precision-guided munitions carried by Apache helicopters, other airborne weapons platforms, or ground based systems. Using the Airborne Target Handover System (ATHS), the Kiowa Warrior is capable of rapidly providing adjustment of conventional artillery or handing targets to other airborne weapons platforms equipped with digital receiving equipment. The Kiowa Warrior is armed with Air-to-Air Stinger (ATAS) and Air-to-Ground (ATG) Hellfire Missiles, 2.75 inch rockets, or .50 caliber machine gun. The ATAS provides the Kiowa Warrior with a mid-range defensive and offensive air-to-air capability against threat aircraft. ATG weapons capability provides defensive and suppressive fire against ground threats and the ability to service high priority targets. Multipurpose Light Helicopter (MPLH) kits provide multi- mission flexibility for limited troop transportation, emergency medical evacuation, external cargo, and rapid deployment relocation.
The first Kiowa Warrior was delivered to the Army in May 1991. It is replacing selected AH-1 Cobra attack helicopters (those that function as scouts in air cavalry troops and light attack companies), and OH-58A and C Kiowas in air cavalry troops. The OH-58D Kiowa Warrior is fielded in air cavalry armed reconnaissance units and attack battalions of selected contingency divisions. The Kiowa Warrior provides the Army with a versatile, lethal, deployable aircraft capable of seeing, fighting, and surviving in all types of terrain, adverse visibility, and battlefield environments, day or night.
The Kiowa Warrior program consists of three parts: a modification effort which upgrades existing OH-58A airframes to the OH-58D Armed Kiowa Warrior configuration, the OH-58D(I) retrofit effort to convert existing unarmed OH-58D Kiowa Warrior aircraft to the armed configuration, and the the OH-58D(R) system improvement effort to upgrade and incorporate safety enhancements on production and fielded aircraft. The prime contractor for the airframe production efforts is Bell Helicopter Textron, Inc., located in Ft. Worth, TX. The three primary Government Furnished Equipment (GFE) subsystems include the Mast Mounted Sight (MMS), Control Display System (CDS), and the T703-AD-700 engine. McDonnell Douglas Aerospace-West, located in Huntington Beach, CA, is the contractor for the MMS. The CDS contractor is Honeywell, Inc., located in Albuquerque, NM. The engine contractor is Allison, located in Indianapolis, IN. Supporting these three parts of the program are various tasks including Training Devices, Special Tools and Test Equipment (STTE) development and production and field support.
The OH-58D is arguably one of the most demanding cockpit workload intensive aircraft in the Army's inventory. The scout/attack mission it performs requires much of its flight profile in extended hovering modes at NOE altitudes, in the presence of terrain flight obstacles such as trees or rocks. The cockpit division of duties typically requires the pilot in the right seat to fly the aircraft, while the left seat pilot operates the Mast Mounted Sight and other aircraft systems. This often requires the left seat pilot to be totally focused heads-down inside the cockpit and thus unable to assist the pilot in detecting drift. In many of these scenarios, both pilots are at times heads-down in the cockpit. The design of the OH-58D is such that the pilot has no flight control aids to assist in maintaining a stabilized hover with the exception of the heading hold mode. The aircraft is equipped with a hover display page on the Multifunction Display, with velocity vectors and other aids to assist the pilot in detecting drift; however, many pilots fail to use these and other aids, such as the ANVIS Display Symbology System (ADSS), as aids to assist them in detecting and avoiding drift.
Inadvertent drift at a hover and subsequent contact with obstacles in the flight path is an all too familiar and recurring accident scenario in the OH-58D Kiowa Warrior. A review of the Army Safety Center data base indicates, that between FY94 to FY01, the Army has recorded 5 Class A, 1 Class B, and 11 Class C accidents as a result of inadvertent drift and contact with obstacles. These accidents have resulted in four fatalities, three non-fatal injuries, and a combined injury and aircraft damage cost of over $40 million.
The most common scenario is drifting laterally or rearward during OGE hover, and striking the tail rotor or main rotor with an obstacle such as a tree, a rock or even another aircraft. Most of these scenarios involve simulated weapons engagements, transmitting digital reports, or situations requiring the crewmembers to be focused inside the aircraft, such as aerial observation. Crew experience ranged from SIP's with thousands of hours, to pilots with very little time. Avoiding inadvertent drift in the OH-58D requires positive coordination between the crew and use of onboard systems to assist in drift detection.
As with most aircraft, the KW flight accident rate changes considerably from one year to the next. The KW accident rate peaked during FY90-91, as operations built toward Desert Shield/Storm. The KW rate has risen progressively from 1995 through 2001, and currently is the highest in the last decade. In response to this upward trend, the Commanding Generals of the Aviation Center, Aviation and Missile Command, Program Executive Officer-Aviation, and the Safety Center collectively chartered KW Aviation Safety Investment Strategy Team (ASIST) to analyze operational experience and develop a coordinated proposal to enhance KW safety.
FORSCOM's OH-58D helicopter fleet is experiencing a significant shortage below documented requirements as aircraft are inducted without immediate replacements into the Safety Enhancement Program (SEP). A FORSCOM representative from FMMC-HT (CW5 Covell) participated/monitored the induction process at Ft Bragg of the first three of 12 OH-58Ds to be inducted from FORSCOM units in FY99. All of the candidates to receive SEP upgrades are the older OH-58Ds in XVIII ABC units. Some of the SEP upgrades are R3 engines/ FADEC, crashworthy seats, and Supplemental restraints (airbags). FORSCOM was short three OH-58Ds going into the program. There are no float or rotatable pool support the program. Get well dates (100% fill) for some units is not expected until after conclusion of the SEP program in FY07.
As of FY03, the Kiowa Warrior was an Acquisition Category II program with an Army acquisition objective of 411 Kiowa Warriors. Due to attrition, at that time the fleet inventory was 373 aircraft.
According to the DOT&E, concerns have surfaced regarding the impact of weight growth on the aircraft's power margin, endurance and autorotation performance, and the impact of several important Interim Statements of Aircraft Qualification restrictions on the operational utility of the Kiowa Warrior. To address these and other concerns, the Army is executing a Safety Enhancement Program (SEP) for the OH-58D Kiowa Warrior that incorporates an improved engine with full authority digital electronic control, crashworthy crew seats, air bags, improved master controller processor, and data modem. The intention of the SEP is to improve engine reliability and crew crash protection, reduce pilot workload during emergency maneuvers, and provide additional digitization capabilities. Current funding for the SEP will modify 301 of the required 354 aircraft. There is an unfunded Army requirement of approximately $90 million for the additional aircraft. The SEP began in FY98. As of December 2003, the upgrade is complete on 192 aircraft.
The DOT&E reports that the Kiowa Warrior is making steady progress in integration testing of its latest control and display system (CDS-4) with the improved data modem, the tactical internet, and fire control systems. Testing results reflect no significant issues. In Operation Iraqi Freedom, SEP-modified aircraft and the addition of engine barrier filters (EBFs) greatly increased the operational effectiveness, suitability, and survivability of Kiowa Warrior units. Prior to the fielding of EBFs, Kiowa Warrior units were experiencing engine failures in sand and dust environments in as little as seven hours of operation. About the best that units could expect the aircraft to operate, without engine failure related problems, was 300 hours. The engine is designed to last between 1,500 and 1,750 hours between overhauls depending on the model. EBF fielded units are experiencing no incidents of engine or compressor erosion and are getting full 1,500- 1,750 hours out of their engines. As a result, units are able to focus more on their mission.
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