The Sherpa is an all-freight version of the Shorts 330 regional airliner with a 5 ft-6 inch square cabin section over an unimpeded hold length of 29 ft. Through-loading is provided via a large forward freight door, and via a full width, hydraullically operated rear ramp door with removable roller conveyors. The C-23 Sherpa is the Army National Guard's answer to missions requiring an aircraft that is capable of faster, higher-altitude and longer-distance coverage than helicopters. The Sherpa comes with a low operating cost due to its simple, robust construction, compared to that of other cargo aircraft.
On November 26, 1996 Duncan Aviation was awarded an $8,000,000 increment as part of a modification to a firm fixed price contract for C-23B, C-23B Plus, and C-23B Plus Alaska life cycle contractor support. Work will be performed in Lincoln, Neb., and was expected to be completed by Sept. 30, 1999. The U.S. Army Aviation and Troop Command, St. Louis, Mo., was the contracting activity.
The objective of the Army aviation modernization strategy is to reduce the size of the rotary and fixed wing fleets to four aircraft types each via the Aviation Restructuring Initiative (ARI). ARI is the vehicle by which the Army intends to accomplish the reduction in fleet size and model types while maintaining the vital capabilities of the fleet. As a product of ARI, Army aviation's overall goal relative to the fixed wing fleet is to reduce the current number of models from 21 to 4. This would include acquisition of the Multi-Mission Medium Tactical Transport (M3T2) [aka Multi-Mission Tactical Transport], currently performed by the C-23 and the C-26.
C-23A Shorts 330
The major military customer was the U.S. Air Force, which bought 18 C-23As for its European Distribution System Aircraft (EDSA) requirement, these being used to shuttle spare parts between the USAFE maintenance and distribution centers and the front-line bases. Based with the 10th MAS at Zweibrücken AB, Germany, the C-23As served from November 1984 until 31 October 1990, when the EDSA program was ended. Four C-23As remained in USAF hands at Edwards AFB, where they were used for the USAF Test Pilots' School, but these have since been retired. Only a few of the C-23A aircraft were used by the Air Force as an all freight regional airliner by Air Force Materials Command. Through-loading is provided via a large forward freight door, and via a full width, hydraullically operated rear ramp door with removable roller conveyors. Eight were diverted to the U.S. Forestry Service, and six were transferred to the Army National Guard, which also ordered 10 more new-build C-23Bs, distinguished by their cabin windows.
On 03 March 2001 a U.S. Air Force Materials Command C-23 Sherpa crashed in a muddy field in Georgia during bad weather an hour after taking off from Hurlburt Field FL. The crash killed three Florida Army Guard crew members, and all 18 Virginia Air National Guard members who were passengers aboard the aircraft. Maj. Gen. Harrison, the Florida National Guard general who convened the investigation, said the primary cause was extreme turbulence and wind shear from a developing thunderstorm. But the formal investigation concluded that the cause of the crash was crew error in loading the plane and a defective weather radar. Investigators believed the aircraft was over its takeoff maximum weight, and loaded with an aft center of gravity. These factors may have caused instability in the bad weather, which caused the plane to break up in the air before it slammed into the ground.
The Collateral Investigation Board found the preponderance of the evidence concluded that the aircraft accident was due to crew error. The board found other factors present but not contributing directly to this aircraft accident. These factors may have influenced the crew's decision making process and aircraft performance. This is normally the case in most aircraft human factor accidents. The board did find the preponderance of the evidence directed the board toward the crew's failure to properly load the aircraft. In particular, the crew's failure to properly manage the weight and balance of the aircraft resulted in an 'out-of-CG' condition that exceeded the aircraft design limits, rendering the aircraft unstable and leading to a violent departure from controlled flight. Once the aircraft departed controlled flight, the rapid onset of significant G-force shifts rendered the crew and passengers incapacitated and unconscious and led to a structural break-up of the aircraft in flight. This ultimately resulted in the aircraft impacting the ground, killing all on board.
This was the third C-23 accident/incident involving aft center of gravity and two of those accidents involved auto-pilot operations. Two of these three accidents resulted in deaths and one involved an uncontrolled decent of 10,000 feet.
US Army Aviation Technical Test Center (USAATTC) has a C-23A aircraft which has been modified to acquire various electronic sensor data in support of the Program Executive Officer (PEO) Intelligence and Electronic Warfare Programs. The Sherpa (C-23A) is owned by Aviation Technical Test Center (ATTC), Ft. Rucker, AL. Originally under the sponsorship of PM, Airborne Reconnaissance Low (PM ARL) and currently being transitioned to PM NV/RSTA, it acts as a UAV surrogate for payload testing. The C-23A Sherpa, with its on-board workstation and capability to carry observers, is ideal for real-time evaluations of various sensor and target detection/recognition systems.
C-23B Shorts SD-360
The C-23B Sherpa aircraft is a light military transport aircraft, designed to operate efficiently, even under the most arduous conditions, in a wide range of mission configurations. The C-23B Sherpa was similar to the C-23A, but with cabin windows. It is a C-23A modified with larger wings, bigger engines, 6-blade propellers, and inward opening doors to provide airdrop capabilities. The large square-section hold, with excellent access at both ends, offers ready flexibility to perform ordnance movement, troop & vehicle transport, airborne/airdrop missions, medical evacuation and is suitable for conversion to other specialist duties such as maritime or land surveillance.
Configured as a troop transport, the Sherpa provides comfortable, air-conditioned seating for 30 passengers, features "walk about" headroom, a removable latrine unit, and has a 500 lb capacity / 345 cu. ft. baggage compartment located in the nose of the aircraft. Additional space for a 600 lb capacity optional baggage pallet is provided on the rear ramp of the aircraft.
During airborne operations, the aircraft accommodates 27 paratroopers. Optionally, it can be outfitted to handle up to 18 stretchers plus 2 medical attendants. The airplane meets Army Short Take-off & Landing guidelines (STOL), can operate from unpaved runways and is equipped with self-contained ground handling equipment. Operational experience with this remarkable aircraft has proven it to have low maintenance costs and low fuel consumption.
On December 8, 1994 Duncan Aviation, Incorporated, Lincoln, Nebraska, was awarded a $5,474,459 modification to a firm fixed price contract for C-23B aircraft life-cycle contractor support. Work was performed in Lincoln, Nebraska, and was expected to be completed by September 30, 1999.
C-23B+ Shorts SD-360
The Short 360 derivative was modified by replacing the rear fuselage of the Shorts 360, with its single tall fin, with the twin tail and rear loading ramp of the Short Sherpa. The modified Short 360 was designated C-23B+ and C-23C. The C-23 multi-role utility airplane is the only cargo airplane in the Army, and is organized into 4 theater airplane companies. Each company has four detachments. The detachments are all located in different states. Each detachment has two aircraft. In the Alaska Army National Guard the UV-18As have been replaced by the C-23B+. Requirements exist to standardize C-23B/B+ systems to include global positioning systems, high frequency radios, airdrop equipment, aeromedical evacuation, and engine upgrades. A few of these aircraft are used as all-freight regional airliners by Air Force Material Command.
The Army National Guard has procured 44 C-23B/B+ Sherpa light cargo aircraft to support theater aviation, cargo, airdrop, and aeromedical evacuation for both state and federal wartime missions. This medium utility transport aircraft entered Army service in 1985. The Army National Guard aviation received three C-23B Sherpa production aircraft in Fiscal Year 1996.
The aircraft can carry up to 30 passengers in airline-type seats, along with palletized cargo, four small pallets, and do airdrop of those pallets, or 18 litter patients plus their medical personnel. It has a range of a thousand miles, cruises up to two hundred knots, and it's square because most of the things the Army has are square rather than round. It has six-and-a-half feet of headroom. It is unpressurized, but if it flies above 10,000 feet for an extended period of time, the crew wears oxygen masks. The Sherpa has a crew of three, but sometimes flies with four man crews if there is a need for two flight engineers.
The grey, 30-foot long Sherpa, begins life as a Shorts 360 Airliner. The Shorts Aviation Company is located in Belfast, Northern Ireland, and is one of the oldest aircraft builders in the world. The airplanes are then sent to Clarksburg, West Virginia, where each is remanufactured into an Army Sherpa. The West Virginia Air Center (WVAC) operated by Bombardier Defence Services Inc. provides Contractor Logistics Support (CLS) for the C-23 Sherpa aircraft operated by the United States Army National Guard (USARNG) and the US Air Force. This entails support of C-23B and C-23B+ aircraft located at 19 different bases in the USA, Puerto Rico and the US Virgin Islands. Additionally, the company provide CLS to the fleet of C-23A aircraft operated by the Air Force Test Pilot School at Edwards Air Force Base CA.
On November 03, 1994 Shorts Brothers PLC, Northern Ireland, was awarded a $36,000,000 modification to a firm fixed price contract for remanufacture of eight SD-360 fixed wing aircraft into C-23B+ aircraft. Work will be performed in Bridgeport, West Virginia, and is expected to be completed by May 30, 1996. Contract funds will not expire at the end of the current fiscal year. This is a sole source contract initiated on June 22, 1992. The contracting activity is the U.S. Army Aviation and Troop Command, St. Louis, Missouri (DAAJ09-93-C-0656).
The C-23C is a modified C-23B aircraft with cockpit upgrade for compliance with global air traffic management requirements. The U.S. Army Aviation and Missile Command, PEO for Aviation (AMCOM) (Huntsville, AL) awarded M7 Aerospace L.P. (San Antonio, TX) a 10-year, $309.2 million, firm-fixed-price contract (W58RGZ-05-C-0124) to perform Life Cycle Contractor Support (LCCS) for C -23C Sherpa cargo aircraft. Under the contract, the company will provide maintenance services, logistical support and management processes to maintain a total of 43 C-23C aircraft, a boxy twin-engine turboprop built in the 1980s by Ireland's Short Brothers, plc, and which now belong to the National Guard. C-23 is the military designation for the Shorts SD-360. M7 Aerospace's principal subcontractor is L-3 Communications Vertex Aerospace LLC (Madison, MS).The contract was competitively procured through solicitation W58RGZ-04-R-0523, which was issued on June 18, 2004, and called for competition limited to small businesses only (NAICS 336411). Proposals were due on August 3, 2004. A total of three offers were received.
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