US Air Force KC-135 Tanker Vanishes Over Strait of Hormuz After Distress Signal

Key facts

• KC-135 Stratotanker issued 7700 distress signal over Persian Gulf near Iran.
• Aircraft took off from Al Dhafra Air Base in UAE, lost signals over Qatar.
• Two H125 helicopters launched from Al Udeid Air Base in Qatar after disappearance.
• Incident occurred on second day of Operation Project Freedom, launched May 4.
• Iran has controlled the Strait of Hormuz since late February.
• US military lost a KC-135 in March in an Iranian attack in western Iraq.
• Strait carries 20% of world's seaborne oil; traffic down over 90% since war began.

Distress Signal Over the Persian Gulf

A Boeing KC-135 Stratotanker, a US Air Force aerial refueling aircraft, broadcast a 7700 squawk code—the international general emergency signal—while flying over the Persian Gulf near Iran on Tuesday, according to flight tracking data from Flightradar24. The plane had taken off from Al Dhafra Air Base in the United Arab Emirates and was operating in support of ongoing military operations when its signals were lost over Qatar. Flight tracking data show the aircraft flew in a circular pattern for a period before beginning its descent for landing. The exact cause of the emergency remains unclear, and no official confirmation has linked the incident to hostile action. on the disappearance, citing Flightradar24 data, but Tehran has issued no statement indicating involvement.

Search-and-Rescue Response Underway

Shortly after the tanker disappeared from radar, two H125 light utility helicopters lifted off from Al Udeid Air Base in Qatar, suggesting a search-and-rescue operation was initiated. Al Udeid, the US military's primary air hub in the Gulf region, sits roughly 500 kilometers northwest of the Strait of Hormuz. US Central Command had not confirmed the incident as of publication. The US military has also not issued any statement on the status of the plane or its crew.

Operation Project Freedom and Rising Tensions

The disappearance occurred on the second day of Operation Project Freedom, a US-led guiding mission launched by President Donald Trump on May 4 to push commercial vessels through the Strait of Hormuz. Iran, which has controlled the waterway since late February, had warned the United States one day earlier to stay out of the strait. Iranian Foreign Minister Abbas Araghchi dismissed the operation as “Project Deadlock,” warning Washington and Abu Dhabi against being “dragged back into quagmire.” The incident came hours after Iran denied responsibility for a strike that set Fujairah’s oil port ablaze on Monday.

Previous Losses and Fleet Vulnerabilities

The US military has already lost multiple tankers during the current conflict. On March 12, a KC-135 went down over western Iraq following a mid-air collision with a second tanker in friendly airspace, killing all six crew members. In March, the Islamic Resistance in Iraq, an umbrella group of Iran-backed armed factions, claimed responsibility for shooting down a KC-135, saying it acted “in defence of our country’s sovereignty and airspace.” Defense experts have repeatedly flagged the KC-135 fleet’s limited battlefield connectivity as a liability in contested zones. The aircraft largely lacks secure beyond-line-of-sight communications, leaving crews with limited situational awareness of threats in the area, as in March.

The KC-135 Stratotanker: A 60-Year-Old Workhorse

The KC-135 Stratotanker is a military aircraft powered by four turbofan engines mounted under swept wings, used primarily for aerial refueling. It has a cargo deck above the refueling system, allowing it to carry both passengers and equipment, and can transfer fuel to other aircraft mid-air. The aircraft has been part of the US Air Force’s operations for more than 60 years. Based on Boeing’s 367-80 design, which also led to the development of the commercial Boeing 707, hundreds of KC-135s remain in service with the US Air Force, Air National Guard and Air Force Reserve. The tanker allows fighter jets, bombers and other military planes to stay airborne longer and travel greater distances, and also supports aircraft from the US Navy, Marine Corps and allied countries.

Strategic Stakes in the Strait of Hormuz

The Strait of Hormuz carries roughly 20% of the world’s seaborne oil supply. Commercial traffic through the waterway has collapsed more than 90% since the Iran war began, with prediction markets placing the odds of a full reopening before June at below 40%. The loss of a US military aircraft in this volatile region—on the heels of a major operation to assert freedom of navigation—underscores the high stakes and the fragility of the current situation. With no official confirmation of the tanker’s fate, and both the US and Iran remaining silent on the cause, the incident risks further escalating tensions in a waterway critical to global energy supplies.

The bottom line

• A US Air Force KC-135 Stratotanker issued a distress signal and disappeared from radar over the Strait of Hormuz on Tuesday.
• The incident occurred on the second day of Operation Project Freedom, a US-led mission to reopen the waterway to commercial traffic.
• Two search-and-rescue helicopters were launched from Al Udeid Air Base in Qatar.
• The US military has not confirmed the incident, and no cause has been established; Iran has denied involvement.
• The KC-135 fleet has been flagged for limited battlefield connectivity, and the US has lost multiple tankers in the current conflict.
• The Strait of Hormuz, through which 20% of global seaborne oil passes, has seen traffic drop over 90% since the war began.