If you are cruising at FL 290 and cannot contact Boston Center, what frequency should you attempt to contact?

When flying at FL 290 and unable to establish contact with Boston Center, the correct action is to attempt to contact both frequencies, which is why the choice that includes both is the correct one. In cases where there is a loss of communication with a primary air traffic control facility, pilots are instructed to use the backup frequencies that can accommodate aircraft at higher altitudes.

UHF frequencies like 348.7 may have coverage for aircraft operating in certain segments and could potentially give access to air traffic services. Simultaneously, VHF frequencies such as 128.325 MHz are widely used for air traffic control communications and may provide an alternative contact method.

Utilizing both frequencies allows a pilot to maximize their chances of re-establishing communication in a situation where primary contact has failed. It ensures that if one frequency is not working due to equipment issues, the other might successfully establish contact. This approach aligns with aviation protocols designed for safety and effective communication in flight operations.