The performance of three Loran-C airborne receiver/computer systems was investigated during flights in the U.S. Northeast Corridor to determine the feasibility of using Loran-C signals and equipment to navigate V/STOL vehicles in that area. Flight tests were conducted in a C-130 and DC-6 fixed wing aircraft, and a CH-47C helicopter. Tracking radar was used on several of the flights to determine the airborne Loran-C equipment accuracy. Oscilloscope photographs of the received signals and strip chart recordings of the received 50 kHz to 150 kHz spectrum were used to establish the Loran-C signal, noise, and interference conditions throughout the Northeast Corridor. Test results showed that existing Loran-C signals and the systems did establish aircraft positions from the ground to operating altitudes in the Northeast Corridor. However, the equipment interfering signal rejection ability and reliability were not adequate for immediate operational use. (Author).

This report presents the results of a comprehensive flight test evaluation of a production airborne Loran-C navigator. The test were performed on a FAA approved helicopter route in the Northeast Corridor, at NAFEC in Atlantic City, New Jersey and in the Gulf of Mexico. The test aircraft used were United States Coast Guard HH52 and HH53 helicopters. The test period was from June 1978 to January 1979. The test plan and test objectives were developed jointly by the United States Coast Guard and the Federal Aviation Administration and Systems Control, Inc. (Vt), Champlain Technology Industries Division. The flight test profiles and procedures were developed for the following reasons: (1) to assess the ACceptability of Loran-C navigation in the operational ATC environment of the Northeast Corridor; (2) to determine the system use accuracy for Loran-C for enroute, terminal and non-precision approach flight; (3) to evaluate the Loran-C navigator performance in several offshore missions. The primary conclusions of this flight test evaluation were: the navigator was acceptable in the operational environment of the Northeast Corridor for both enroute and point-in-space approaches; the navigator satisfied AC 90-45A crosstrack accuracy requirements for enroute, terminal area and non-precision approaches; the production navigator satisfied alongtrack AC 90-45A accuracy requirements for enroute and terminal area, but not for non-precision approaches; the navigator performed acceptably during all phases of offshore testing. (Author).

The Transportation Systems Center, Langley Research Center, the Federal Aviation Administration, and the Agency of Transportation, State of Vermont conducted a program sponsored by the Research and Special Programs Administration of the Department of Transportation to evaluate LORAN-C as a supplement to existing navigation aids for general aviation aircraft, particularly in mountainous regions of the United States and where VOR coverage is limited. This report highlights results obtained in completing 215 non-precision approaches and 104 flights. The flights, initiated in the summer months, extend through four seasons and practically all weather conditions typical of northeastern U.S. operations have been experienced.