USAF Stratotanker Squawks 7700 Emergency Near Doha

The fight for control of the Strait of Hormuz flared up Monday and into the overnight hours, with IRGC forces reportedly striking multiple commercial vessels and a UAE oil refinery.

The one positive development: with U.S. forces on heightened alert, two U.S.-flagged merchant ships successfully transited the maritime chokepoint as Project Freedom began, marking the first visible move by the U.S. Navy to unfreeze the world's most critical energy corridor.

U.S. Central Command, or CENTCOM, said its aerial assets in the Hormuz area were busy on Monday, with helicopters and other aircraft combating IRGC forces to ensure the safe transit of the two ships.

Flight-tracking website Flightradar24 reported early Tuesday that a U.S. Air Force Boeing KC-135 Stratotanker, a military aerial-refueling aircraft, squawked "7700" after operating in a tight pattern near the Hormuz chokepoint.

"A U.S. Air Force KC-135 is squawking 7700, flying in the direction of Doha," Flightradar24 wrote on X.

A US Air Force KC-135 is squawking 7700 flying in the direction of Doha. https://t.co/wxldcwLX1g

For more information on ‘Squawking 7700’ please see https://t.co/nW7vZ4JgMF pic.twitter.com/AYffNcZGKt

— Flightradar24 (@flightradar24) May 5, 2026

Flightradar24 had no additional information on why the KC-135 crew squawked 7700. Some possible reasons include:

• Mechanical failure

• Engine problems

• Fire or smoke

• Medical emergency

• Loss of pressurization

• Fuel emergency

• Other serious onboard problems

Separate but notable, UBS analyst Dominic Ellis provided clients with energy market commentary following the overnight Hormuz chaos:

Brent Down From Intraday Highs, Though Up 7% Relative To Monday's Low The fragile ceasefire in the Persian Gulf seems to be on the verge of collapse after Iran responded to Project Freedom, the US effort to restart transit through the Strait of Hormuz, by launching attacks on commercial vessels and energy infrastructure in the region.

Brent is down from the intraday high over $114/b but remains close to $113/b, up almost 7% relative to Monday’s low.

The US denies Iranian claims that a US navy vessel was hit, but acknowledges damage to a South Korean cargo vessel. The UAE blamed an Iranian drone attack for a fire in the Fujairah Oil Industry Zone, concerning given the role Fujairah plays in allowing some regional oil exports to bypass the Strait of Hormuz.

Maersk said on Tuesday that one of its vessels, the US-flagged Alliance Fairfax, was successfully escorted through the Strait of Hormuz by US military assets, part of a US convoy involving at least one other US-flagged merchant vessel according to US Central Command.

It remains to be seen whether this was a one-off or evidence that the Iranian ability to disrupt flows via the Strait has been seriously degraded.

Oil could rapidly retreat below $100/b if it appears that the Iranian stranglehold on the Strait has been weakened, but even intermittent attacks on shipping would keep the geopolitical risk premium elevated and the volume of tanker traffic well below the level required for the oil S/D balance to normalise.

The next few days will be crucial – keep an eye on shipping data in the UBS Hormuz Tracker.

CENTCOM and U.S. officials have not provided any details so far on the KC-135's emergency or what caused it.