UV-18A Twin Otter

In 1963 the Low-Cost Plane Design Committee of the Association of Local Transport Airlines (ALTA), the trade association of the local service airlines, had issued a report calling for a new aircraft designed specifically for low-density air service-a so-called "DC-3 replacement." In 1964, Pratt & Whitney of Canada, an engine manufacturer with a history of successful aircraft engines, announced a new turboprop engine, the PT-6, which was highly suitable for aircraft in the 12,500-lb commuter category. The availability of an appropriate engine, along with the impetus of the ALTA report, contributed to the development of two new twin-turboprop airplanes in the 15- to 19-seat range that were well suited to commercial low-density markets: the Canadian DHC-6 Twin Otter, made available in 1966 and designed primarily as a general-purpose bush airplane; and the Beech 99, first produced in 1967 for the corporate and air-taxi market. By 1970, commuter operators had purchased 134 of these two aircraft, representing about 75 percent of the over-15-seat aircraft in the commuter fleet.

The UV-18A 'Twin Otter' is the military version of the DeHavilland DHC-6 with optional float and ski fittings. The aircraft have crew and passenger oxygen systems and a navigation/communication package which gives it an all-weather capability. It has a cruise speed of 150 knots, a service ceiling of 25,000 feet and a range of 700 miles. Designed to replace DHC-3, DHC-6 made its first flight on May 20, 1965. This general-purposed civil and military transport, used by regional airlines in Alaska and other areas with short or rough runways, entered production early in 1966. By September 1982, over 800 DHC-6 were built, and by the end of production in 1988 a total of 844 aircraft were built for various military and commercial customers.

Airlift support for the US Air Force Academy cadet parachuting program is provided by three UV-18B aircraft which carry a pilot, copilot and up to 17 jumpers. These Twin Otters are the only three owned by the Air Force. In the MSAG Antenna Test and Evaluation conducted 25-31 August 1998 in Marina CA, the NPS/CIRPAS UV-18A Twin Otter provided the surrogate UAV function during a test and evaluation of the MSAG ITT Antenna under development by the Joint Projects Office. Imagery from the Twin Otter was received by the multi- source capable antenna based at the CIRPAS facility in Marina. In the Alaska Army National Guard the UV-18As have been replaced by the C-23B+.

Because the DeHavilland DHC-6 Twin Otter is a highly maneuverable aircraft which can be flown slowly (80-160 knots/150-300 km/hr) and in tight circles, these aircraft are considered extremely versatile survey airplanes. The US Geological Survey (USGS) utilizes the NOAA Twin Otter as a platform for aerial surveys of coastal areas before and after major tropical storms. Combining oblique video and 35 mm photography, the scientists can assess the coastal erosion caused by major meteorological events. The video camera is mounted on a tripod secured to the covering of the belly camera port, and the aft section of the door on the left side is removed to facilitate photography. Scientists working in the aft section of the aircraft are required to don safety harnesses and secure the harnesses to the aircraft during the entire flight. A global positioning system (GPS) data drop located in the rear of the aircraft on the right side provides researchers with continuous latitude/longitude information. Additionally, a scientist with a 35 mm camera continually photographs the shoreline from the left bubble window. To accomplish this mission, the aircraft must be flown at 100 knots ground speed and at 500 feet above ground level. The auxiliary fuel tank may be present or absent, according to the endurance requirements of the project.

The Twin Otter is a safe, stable platform for offshore low level marine animal surveys. In the past, the NOAA Twin Otters have been utilized to assess populations of many species of pinnipeds, cetaceans, fish, and sea turtles. The aircraft is routinely flown at 90-110 knots during survey flights and is highly maneuverable enabling smooth execution of steep turns. HF radios allow for communications when the aircraft is a long distance from the shoreline. While most animal surveys are flown during the day and under visual flight rule conditions (VFR), the aircraft is equipped for flight into instrument meteorological conditions (dual VOR, dual ADF, dual GPS, DME, color weather radar) and icing conditions (pitot heat, prop deice, wing and horizontal stabilizer deicing boots, engine intake deflectors).

In 2000 a quick Reaction audit was requested by the USPFO on the transfer of 1.18 million dollars of UV-18 Fixed Wing aircraft parts to the Navy in exchange for the Navy's purchase and delivery of UH-60 helicopter fuel tanks. The various agreements negotiated and transfer actions taken, were performed outside normal operating procedures, without USPFO approval. Agreements were not negotiated IAW DODI 4000.19 and NGR 5-2. Disposition procedures in AR 710-2 were not followed and a contracting officer was not used to obtain the Fuel tanks IAW the FAR. The UV-18 parts were given to an agent of the Navy without following standard procedures, obtaining proper approvals, or using any documentation for the disposition. The UH-60 fuel tanks were also not certified by the Army as air worthy. In one week the Navy's agent created a company, loaded the parts on a truck, sold $650K of the parts to a company in Canada, and purchased a new airplane with the proceeds. As a result, the ARNG lost control and accountability for the parts, missed out on a reimbursable opportunity and created numerous legal issues that are currently being investigated by CID and DCIS. The final audit product provided investigators and command with a tool for focusing an investigation, addressing regulatory violations and avoiding similar situations in the future.