The bomber issued a 7700 code, known as Squawk 7700, which is an international signal for a general emergency or distress. Multiple reports indicate the emergency occurred as the bomber was returning to a base in the west of England. The aircraft departed from RAF Fairford in Gloucestershire on Monday evening and returned shortly after 09:00 GMT on Tuesday. It was observed circling at approximately 10,000 feet just east of Southampton before beginning a steady descent.
Flight spotters believe the 7700 code was issued due to a loss of cabin pressure while the aircraft was flying over the Solent, but the reason for the distress signal has not been confirmed. The US Air Force has been approached for comment.
The bomber is part of the US task force currently deployed at a RAF base in the UK. RAF Fairford is capable of hosting all three kinds of long-range bombers in the USAF—the B-1, B-2, and B-52—due to its long runway.
The B-52 has been used by the USAF since the 1950s, and the B-52H variant is known for its ability to carry a huge payload of missiles in excess of 30 tonnes and its longevity. According to manufacturer Boeing, the majority of the USAF's B-52H bombers were delivered in the 1960s and are expected to operate into the 2050s.
The arrival of USAF bombers at RAF Fairford has drawn crowds of plane enthusiasts to the area. People living in the nearby village of Down Ampney say the noise of the bombers taking off is so loud it causes houses to shake and sets off car alarms.
This deployment comes amid broader military agreements, as the UK government announced on 1 March that it has agreed to allow British military bases to be used for 'defensive' strikes on Iranian missile sites.