Incident Overview
On 1 August 2015, the crew of a Boeing 787-800 encountered difficulties when attempting to establish communication over the North Atlantic (NAT) MNPS airspace. After reaching the limit of VHF communication coverage, air traffic control instructed the crew to contact the next sector on HF frequency. Although the crew received transmissions from both other aircraft and ground stations correctly, they were unable to establish two-way communication with the controller.
Communication Attempts
The crew made multiple attempts to contact ATC using both onboard HF radios and all available frequencies. Following standard procedures, they relayed their position report to an air traffic control center through another aircraft. Upon entering the next air traffic control sector, the crew successfully established HF contact using one radio, while the second remained inoperative. The remainder of the flight proceeded without further communication issues.
Aftermath
After consultation with the aircraft manufacturer, a decision was made to replace both HF radios and the antenna coupler. The investigation concluded that the cause of the incident was a malfunction of the onboard HF radios and/or the antenna coupler.