UK F-35 Accident Probe Highlights Broader Carrier Concerns

sunken F-35

A sonar image shows the sunken F-35 lying intact and inverted on the Mediterranean Sea floor at a depth of 6,600 ft.

Credit: UK Defense Ministry

The UK’s first loss of a Lockheed Martin F-35 was an ignominious one.

A bright-red engine intake blank—designed to protect the aircraft’s engine from foreign objects and prying eyes—ended up blanking the engine in another way: It prevented air from reaching the fans as the F-35B registered ZM152 made its takeoff run on the deck of the HMS Queen Elizabeth in November 2021. 

Rather than launch into the sky, the aircraft belly flopped over the ship’s ski jump into the Mediterranean Sea. The pilot, realizing the peril of the situation, aborted the takeoff and ejected from the aircraft, landing back on the deck, his parachute snagging on the ramp’s lighting.

As the F-35 floated in the sea along the 60,000-ton ship, the large, spongy intake cover, which had eluded inspection from ground crews prior to flight, emerged from the wreckage drifting in the sea.

  • Accident occurred on final leg of HMS Queen Elizabeth’s first deployment
  • Lack of personnel numbers, fatigue hindered UK F-35 operations

But as simple as the cause of the accident was, the incident—the subject of a long-awaited report finally published on Aug. 10—has also raised significant questions about the UK’s approach to embarked operations, personnel readiness and training, equipment resource management and even the security of the UK Joint Strike Fighter program, making no fewer than 46 recommendations.

The accident happened just after the ship, with UK and U.S. F-35s embarked, reentered the Mediterranean Sea on its final leg of the ambitious Carrier Strike Group 2021 deployment to the Asia-Pacific region, the first operational task of the UK’s Carrier-Enabled Power Projection capability. 

The air intake blank formed part of a set of protective equipment called “red gear” that is fitted to the sensitive parts of the aircraft when not flying. This equipment would generally be fitted to the aircraft “to protect aspects of the aircraft from espionage” when the ship was in port but not normally when the ship was at sea because the intake blanks could be blown out by modest winds or aircraft launching nearby—and there had been numerous accounts of that happening, the report stated. But the crew was not always logging when such equipment was fitted or removed, the report stated.

Part of this lapse was due to a lack of resources, the report found. The 617 Sqdn., then and still the UK’s only frontline F-35 unit, was deployed on the carrier with 113 personnel. By comparison, U.S. Marine Corps squadron VMFA-211 took 255, despite having just two more aircraft than the British unit.

Furthermore, to deploy those 113 people, the 617 Sqdn. had to borrow from the UK’s F-35 training unit, 207 Sqdn. This lack of personnel, plus UK demand for a baseline flying rate associated with so-called surge operations, resulted in significant levels of fatigue.

Those flying rates, the report stated, resulted in decreased opportunities for fresh air and recreation for those personnel without routine access to outside spaces, further contributing to fatigue. Some witnesses described the Queen Elizabeth carrier as “the largest submarine in the Navy.” 

Personnel often needed treatment for heat stress; temperatures on the flight deck frequently exceeded 40C (104F). Although the squadron aimed to rotate personnel to avoid the heat, “the length of time required to attend aircraft during see-offs meant personnel often exceeded this guidance,” the report stated. 

The report also asserted that commanders needed to better understand “safety and security requirements for a fifth-generation platform,” noting that the introduction of special access programs, such as the F-35, had “elevated security thresholds” and placed “extra strains on safety.”

Some of these issues are being addressed. Commanders told Aviation Week last summer that more personnel would be deployed with squadrons during embarked operations, in response to the accident report’s findings (AW&ST July 11-24, 2022, p. 18).

The aircraft sank shortly after the incident, and a £2.63 million ($3.3 million) search-and-recovery operation for the wreckage located the aircraft several weeks later intact and upside down on the seabed, at a depth of 2,000 m (6,600 ft.).

In his closing remarks in the report, Air Marshal Steve Shell, director general of the UK Defense Safety Authority, said the UK’s Lightning Force—the joint Royal Navy-Royal Air Force organization operating the F-35—had not yet reached a “critical mass,” with squadrons unable to support one another’s deployments without infringing on their own operations.  

“Until critical mass is reached, defense must recognize the trade-offs between readiness, growth and safety,” Shell said. He added that with UK F-35 operations increasing and the government wanting to expand carrier deployments, the accident was a “timely reminder to take stock and ensure we are giving the Lightning Force the best chance of success.”

Tony Osborne

Based in London, Tony covers European defense programs. Prior to joining Aviation Week in November 2012, Tony was at Shephard Media Group where he was deputy editor for Rotorhub and Defence Helicopter magazines.