A U.S. Air Force C-17A Globemaster III returned to Christchurch, New Zealand, after receiving a notice warning of potentially hazardous space activity. The aircraft had departed Christchurch International Airport on Tuesday at 9 a.m. local time and landed back at the airport at about 11:30 a.m., Defense News reported, citing New Zealand Civil Aviation Authority and U.S. Pacific Air Forces statements as well as flight-tracking data.

The aircraft was flying toward Antarctica on what a Pacific Air Forces spokesperson described as a routine resupply mission scheduled for this time of year. Flight-tracking data cited in the report identified the aircraft by the call sign ICE28. After the warning was issued, the C-17 returned to Christchurch.

The warning followed notification from the Russian Air Traffic Management Corporation to New Zealand’s Civil Aviation Authority. The Russian agency advised the CAA of a planned missile launch and an associated potential hazard to international airspace within New Zealand’s Oceanic Flight Information Region, the CAA said.

The CAA responded by establishing a danger area and issuing a Notice to Airmen, or NOTAM, to alert aircraft operators to the potential hazard. The authority said the notice did not prohibit aircraft from entering the area. Operators make decisions based on the information available, according to the CAA.

NOTAMs provide information about potential hazards to support operational decisions and flight planning. The CAA described the issuance of a NOTAM after receiving such a hazard notification as normal practice for airspace authorities and air traffic service providers.

The relevant Oceanic Flight Information Region covers roughly 30 million square kilometers over parts of the South Pacific Ocean, Southern Ocean and Tasman Sea. The CAA said much of the region lies over international waters, where New Zealand has limited control over activities.

Christchurch is used by U.S. and New Zealand defense forces for operations and logistical support connected to Antarctic science programs. The Pacific Air Forces spokesperson called the city “the gateway to Antarctica” and said both countries conduct operations and logistical support from Christchurch in support of those programs.

The flight took place during the period associated with the U.S. Air Force’s annual Winter Fly-in, or WinFly. The period generally occurs toward the end of August and delivers teams, equipment and cargo to McMurdo Station and Scott Base in Antarctica ahead of the research season. The Pacific Air Forces spokesperson described the flight as a routine resupply mission but did not characterize it as directly part of WinFly.

Operation Deep Freeze supports the U.S. Antarctic Program, which is managed by the National Science Foundation and enables continuous scientific research in the region. A 2012 Air Force release cited in the report said a C-17 delivered more than 300 passengers and 230,000 pounds of cargo to Antarctica during that year’s WinFly.

The C-17A Globemaster III is a cargo aircraft capable of transporting troops and cargo to main operating bases or forward bases in deployment areas. It can also perform tactical airlift, airdrop and aeromedical evacuation missions.

In this case, the aircraft’s scheduled trip ended with its return to Christchurch after the space activity warning. The incident illustrates how a hazard notification within an oceanic flight information region can affect an ongoing military logistics flight without formally closing the area to aircraft.