Military Aerospace Technology Today is: Oct 10, 2007
Volume: 6  Issue: 1
Published: Feb 21, 2007

Download Who's Who in DISA 2007

Download 2007 VETS GWAC Catalog

Download DISA 2007 Contracts Guide

Download PEO-EIS 2007 Catalog

Military Aerospace Technology Online Archives

This article was Originally Published on May 01, 2002 in Volume: 1  Issue: 2

No 'Black Hawk Down'

Sikorsky begun UH-60 production in 1978, making the earliest delivered aircraft nearly 24 years old. Under helos' rebirth, aircraft will have numerous improvements.

By Rudolph W. Beckert

Print this Article
Send a Letter to the Editor

Sikorsky began UH-60 helicopter production in 1978, making the earliest delivered aircraft nearly 24 years old. UH-60A and UH-60L helicopters are movers of men and supplies for the U.S. Army. Because of its size, performance and survivability, the Black Hawk has multi-mission capabilities, including movement of troops and supplies, search and rescue, special operations, medical evacuation and command and control.

Last year the company signed an Army contract for research, development, test and evaluation (RDT&E) of the UH-60M Black Hawk, which is the beginning of an effort to upgrade as many as 1,200 Army fleet aircraft during the next 25 years. This means that Black Hawks will be in operational use to the year 2040 and beyond. With the RDT&E program underway, two UH-60As and one UH-60L helicopter have already been inducted into the disassembly and inspection process at Sikorsky subsidiary.

The Black Hawk has been employed in every significant U.S. military ground operation from Grenada to Afghanistan, including service in Somalia, featured in a movie this year entitled "Black Hawk Down". It is engaged in a wide range of other tasks, including armed attack, electronic warfare, humanitarian aid, fire-fighting, and executive transport.

Derivatives have been spawned for all U.S. military services and 25 countries worldwide.

The capabilities of this aircraft were not an accident. Its requirements were established during and after the Vietnam War era, and are a direct result of combat helicopter shortcomings experienced during that conflict. The lessons learned in Vietnam included the need to fly faster and farther from higher elevations at higher temperatures while being able to withstand ballistic hits and continue the mission.

Systems would require the ability to continue operation if hit by small-arms fire ranging from 7.62 mm to 23.7 mm. In addition to aircraft hardware, survival of flight personnel became a primary ingredient in the combat design of the aircraft. The flight crew required armored, crashworthy seats.

Redundancies Cited

If mortally hit and high-impact ground contact was inevitable, the helicopter was required to withstand g forces of 20g forward, 20g vertically, and 18g laterally, three times the capability of existing helicopters. This equated to a 38 foot-per-second vertical crash, survivable by flight crew and troops. Reliability of the design would require triply redundant hydraulic and electrical systems, dual engines, an auxiliary power unit, separated dual controls, a self-sealing crashworthy fuel system and other system redundancies throughout the helicopter.

By way of history, these requirements became the specification for the Utility Tactical Transport Aircraft System (UTTAS). Later named Black Hawk, the specification became a production reality that has been maintained since inception. Black Hawk's ability to save lives was experienced in two significant crashes during hostilities in Mogadishu, Somalia. Both aircraft had sustained multiples of hits by small-arms fire and continued their missions, only to be severely damaged by rocket-propelled grenades, unguided explosives capable of extreme damage to the helicopter. In other designs, it would be highly unlikely for anyone aboard to survive the crash impact.

On Dec. 23, 1976, Sikorsky won the UTTAS competition against Boeing Vertol's UH-61 and was awarded a contract for the UH-60A, powered by General Electric T700-GE-700 engines. The Low Rate Initial Production (LRIP) quantity of 15 helicopters began deliveries in October 1978, and by the mid-1980s, production rates in excess of 100 helicopters per year were achieved. In all, more than 1,100 UH-60A helicopters were produced for United States and international militaries.

In 1989, the UH-60L became the production standard. Its upgrade included more powerful T700-GE-701C engines, a transmission system with increased ratings and durability and numerous airframe and subsystem reliability improvements. As a result of this design progress, higher payloads, increased hover weights, and faster forward flight speeds were achieved with an approximate 40 percent reduction in operating and maintenance costs.

Since 1989, more than 1,000 UH-60L helicopters and its S-70 variants have been delivered to the U.S. government and international customers. UH-60L production deliveries are planned for the Army through fiscal year 2007, at which time production deliveries of the new UH-60M are positioned. When naval variants are included, more than 2,500 Hawk family helicopters have been delivered since 1978 and more than five million flying hours have been logged. Under licensed co-production, Mitsubishi Heavy Industries in Japan and Korean Air Industries in Korea have produced an additional total of nearly 200 Hawk-version helicopters.

Upgrade Helos Listed

Under last year's $219.7-million RDT&E contract, the first aircraft scheduled for upgrade is a UH-60A built in 1985 that last served with the 507th Medical Evacuation (Medevac) unit at Fort Hood, TX. It will provide the basis or "proof of concept" for the "A" to "M" element of the plan, and it is hoped that the task can be accomplished on schedule and at reasonable cost.

The second aircraft is a UH-60L from Fort Stewart, GA, built in 1989, and representing an early model of this type. The last is a UH-60A from the Naval Test Pilot School in Patuxent River, MD. This UH-60A was delivered in 1978, the third production helo to roll off the assembly line. It will be upgraded to the UH-60M Medevac configuration. The inducted aircraft were chosen to represent a spectrum of age and configurations with high-time airframe hours.

The rebuilt aircraft will have improved payload, new digital cockpit displays, a strengthened fuselage, new composite spar, wide-chord blades, and more powerful engines. The Army has identified these rebuilt aircraft as "re-capitalized", and each will provide an additional 20 years of service life with lower maintenance costs than exhibited by the current fleet. A fourth UH-60M will be produced as a new aircraft under the program, and will be the test and qualification model for future production of this model type.

The company will disassemble the aircraft, inspect parts, recondition the cockpit, tail cone and tail structures, and ship the rebuilt components and assemblies to facilities in Stratford, CT. There, a newly manufactured cabin and transition section will be fitted with the reconditioned components. Dynamic components will be reconditioned or replaced, and high speed machining will be utilized to reduce cost, complexity and parts count of new airframe components.

All UH-60A aircraft upgraded to the UH-60M configuration will receive an improved durability main gearbox, the standard for the UH-60L. A new glass cockpit with data bus, four multi-function displays, two control display units, a modern flight control computer, and a new avionics suite will be installed. With the new electronics, a narrower instrument panel can be incorporated to significantly improve lower cockpit window visibility.

'Dual-use' Program

The UH-60M will utilize new rotor blades developed under a "dual-use" program. This process capitalizes on development of commercial components that can be used in military systems. Rotor blades are of composite spar construction, replacing the current titanium spar, and are redesigned to add 16 percent more chord. New, composite anhedral blade tips will replace the current aluminum trapezoidal tips.

The new rotor blades provide about 500 pounds more lift than the current blade, improved flight maneuver and speeds that are 15 to 20 knots higher than the current UH-60L. This wide-chord blade has been tested on Black Hawk and is being produced for the civil S-92 helicopter currently undergoing flight certification.

A new T700-GE-701D turbo shaft engine under development by the Army will add more power, boosting payload by about an additional 400 pounds, and will provide a significant improvement in durability. The combination of the improved engine, main gearbox, and resetting the clock on other components will significantly reduce the operation and support costs of the UH-60M when compared to earlier models.

The program faces an aggressive schedule. First flight of the UH-60M is scheduled for 2003. Each of the four aircraft will enter a test and evaluation program that will lead to a production decision by the Army in 2004. With that approval, fiscal year 2004 funds could be released for a planned LRIP quantity of 10 remanufactured UH-60M helicopters, to be delivered during 2005 and 2006. Production quantities for new UH-60M helicopters will be established during the upcoming years, but re-capitalized aircraft will be processed over the next 20 years, ultimately resulting in a total quantity of about 1,200 UH-60Ms.

In an effort to maintain continued operational readiness for the basic UH-60A, the Army will recondition a bridge quantity of about 200 UH-60A airframes beginning in 2003. This process is sometimes referred to as a "service-life extension program". Under an engineering service contract, Sikorsky will identify airframe and dynamic system components that will be repaired or replaced to extend airframe life.

Near 'Zero-time' Planned

New system components will be provided as a kit of parts to Corpus Christi Army Depot in Texas, where the inducted aircraft will be near "zero-timed". This means the airframes will be completely rebuilt, permitting UH-60A operational capability to continue seamlessly until future but ultimate induction of these airframes into the UH-60M upgrade program.

Under the U.S. Army program, the manufacturer will have established a standard upgrade process that applies to almost all Black Hawk models, extending use of the helicopter for 20 or more years. This is especially important to international users that are experiencing high airframe hours, and may be critical to those users that have mission performance requirements that exceed current aircraft capabilities.

Between 1984 and 1994, some 280 UH-60 and S-70A helicopters were delivered internationally, some of which have achieved very high operating hours. These and more recently delivered aircraft are candidates for induction in the upgrade program. As a direct benefit, the international Black Hawk community will achieve reduced operating costs and extended life, avoiding obsolescence or replacement with new aircraft.  L

Rudolph W. Beckert is a consultant for Sikorsky Aircraft Corp., having retired after a career of 38 years. He currently provides consulting services to the helicopter industry through Beckert Consulting, Inc., a company he founded in July 2000.

To Top

Home | Archives | Events | Contact | Advertisers | Subscribe

Defense Consulting & Outsourcing  Military Advanced Education  Military Geospatial Technology  Military Information Technology  Military Logistics Forum  Military Medical Technology  Military Training Technology  Special Operations Technology

Web site by Foster Web Marketing

© 2007 Kerrigan Media International, Inc. All rights reserved. Kerrigan Media International, Inc. ("we," "us") provides publications, information, content, text and graphic material, and other products and services (all and/or any portion of which, are individually and collectively referred to as "KMI Publications"). KMI Publications also refers to web sites, production, processing and communications facilities whether owned, operated or provided by us ourselves or in conjunction with others pursuant to contractual arrangements. KMI Publications are for informational purposes only and your access, use, subscription to or display of any KMI Publications is subject to applicable U.S. law and regulation, as well as certain international treaties. You may access and use KMI Publications and download and print or create only one copy of content or the information in KMI Publications, solely for your own personal use. You may not republish, upload, post, transmit or distribute materials from any KMI Publications, without our prior written permission. Modification of or useof any KMI Publications for any other purpose is a violation of our copyright and other proprietary rights, and is strictly prohibited. All trademarks, service marks, and logos used on or in KMI Publications are either ours or are used with permission.