C-23 Sherpa
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.
Only a few of the C-23A aircraft are 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.
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 In the Alaska Army National Guard the UV-18As have been replaced by the C-23B+.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 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 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.
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 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. 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.
On 03 March 2001 a 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.
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.
