What happened
On October 21, 2015, a Boeing 787-800 was operating in the North Atlantic (NAT) MNPS airspace when the crew encountered a significant communication failure. The crew was unable to establish radio contact using either of the aircraft's two HF radio sets. While the transmissions from the aircraft were illegible, the Selective Calling System (SELCAL) functioned correctly, allowing ground stations to alert the crew of incoming calls.
Due to the loss of HF capability, the crew maintained contact with Air Traffic Control (ATC) using satellite communication (Satcom) in accordance with established procedures. Other critical surveillance and communication systems, including ADS (Automatic Dependent Surveillance) and CPDLC (Controller Pilot Data Link Communications), remained fully operational throughout the flight.
The investigation
The investigation, conducted by the operator, focused on determining the source of the radio failure. Following consultations with the aircraft manufacturer, it was determined that the failure was localized to the specific aircraft involved. The investigation led to the decision to replace both HF radio units and the antenna coupler.
Findings
- The primary cause of the communication loss was a malfunction of the onboard HF radio stations and/or the antenna coupler.
- The failure was isolated to a single aircraft, as no similar incidents had been reported by other operators of this aircraft type at the time of the investigation.