Sea Dragon helicopter: Troubled past, uncertain future

By Mike Hixenbaugh
The Virginian-Pilot


The Navy started making plans in the late 1990s to retire the most powerful and crash-prone helicopters in its fleet.

By then, several of the service’s MH-53E Sea Dragons – the only U.S. helicopter capable of towing a specialized sled through water to detect and clear mines – were approaching the end of their planned service lives, and Navy leadership needed to make a decision: Invest a significant amount of money to keep the helicopters flying, or develop a replacement.

They chose the latter.

But a plan to outfit a smaller helicopter to hunt underwater mines fizzled. New technology didn’t work as designed. Shipping lane security threats increased after 9/11, along with demand for the Sea Dragon’s unique capabilities. And as a result, retirement of the Cold War-era aircraft got pushed back from 2008 to 2012, and then from to 2012 to        sometime next decade.

Over time, “the Navy slowly but surely kind of forgot” about the Sea Dragon community, Capt. Todd Flannery said in an interview with The Virginian-Pilot last fall, a year after a spate of crashes overseas prompted the service to take a hard look at the program.

The Navy found systemic problems: Maintenance was being conducted haphazardly. Standard operating procedures were being skipped. Only a few Sea Dragons were ready to fly at any given time, and among them, a third weren’t even equipped to perform the core mine clearing mission.

The squadrons had developed their own ways of doing business, Flannery said last fall, essentially “finding ways to do more with less.”

“It was a failure of many things,” said Flannery, the commander of Helicopter Sea Combat Wing Atlantic. “It was a failure of leadership. It was a failure of maintenance. It was a failure of operations. There were just many things that came to a head that led to this.”

Last year, the Navy committed millions of dollars to turn things around. It upgraded the aircraft with night vision technology and new sensors to detect mechanical problems. It added dozens of maintenance personnel. It  beefed up pilot training. And it tapped Flannery, a career SH-60F Seahawk pilot, to implement leadership and cultural changes at the service’s two helicopter mine countermeasures squadrons, HM-14 and HM-15. Both are based at Norfolk Naval Station.

The investments of attention and money were paying off, Flannery said in October. The Sea Dragon community still had a long way to go, but it was back on the right path. “We’re not there yet by a long shot,” he said at the time.

Then last month, another Sea Dragon went down, this time closer to home. The watery crash on Jan. 8 off the coast of Virginia Beach killed three of five crew members. The Navy is investigating what caused the accident.

The deadly mishap rocked the close-knit Sea Dragon community. It also attracted attention to a specialized naval helicopter program that had  grown used to flying under the radar.


The MH-53E Sea Dragon, a variant of the Sikorsky-built Marine Corps CH-53E Super Stallion, joined the Navy’s fleet in the mid-1980s. Since then, no Navy helicopter has crashed at a higher rate.

Sea Dragons have been involved in 6.5 serious mishaps for every 100,000 flight hours since 1984, a rate more than three times greater than the rest of the service’s helicopters. Last month’s crash in the Atlantic Ocean was the 15th involving a Sea Dragon and the eighth to result in fatalities.

The helicopter’s demanding mission might have something to do with its below-average safety record, according to former pilots and aircraft maintainers. The Sea Dragon relies on three massive turbo shaft engines to drag a sled roughly the size and weight of an F-250 pickup truck through the water.

Unlike the Marine version, which is primarily used to transport troops and supplies, the Sea Dragon operates under constant stress while towing the sled, usually flying low and taking up a continuous saltwater mist that causes its airframe and components to rust more quickly.

The Navy acknowledges that the Sea Dragon mission is labor-intensive, but the helicopter was designed to pull against 25,000 pounds of sustained tension and never comes close to that while conducting mine sweeps. Flannery said the mission shouldn’t be blamed for its safety record.

For every hour in the sky, the Sea Dragon requires an average of 35 hours of work on the ground – down from more than 50 hours a decade ago, thanks in part to more efficient techniques – making it the most maintenance intensive helicopter in the fleet.

It’s also among the oldest. Originally built to last about 6,000 flight hours, several Sea Dragons have eclipsed that mark. Sixteen of the Navy’s 28 Sea Dragons have had a key bulkhead replaced, extending their service life to 10,000 flight hours.

A number of mechanical and design problems have surfaced over the years.

At least five times over the past three decades, the Pentagon has grounded its entire fleet of Sea Dragon and Super Stallion helicopters. The first mass grounding came in 1984, following a Marine helicopter crash. In 1987, they were grounded again after engineers found a design flaw in the gearbox of the helicopter’s No. 2 engine.

The entire fleet was grounded again in 1992 when a deadly crash in Jacksonville, Fla., revealed a problem in the main rotor assembly.

The fourth mass grounding came in 1996 after a new Super Stallion crashed during a test flight near a Sikorsky factory in Stratford, Conn., killing four crew members. A defective part at the base of the rotor called the swashplate duplex bearing was blamed in that accident.

The swashplate adjusts the angle and tilt of the blades on the rotor to move the helicopter. The faulty bearing was inspected and replaced across the fleet.

Four years later, the same part was singled out after a Sea Dragon went down off Corpus Christi, Texas, killing four sailors and wounding two.        After that crash, the Pentagon ordered every Sea Dragon and Sea Stallion grounded and equipped with a new system to monitor temperature and vibration of ball bearings in the swashplate. The monitors warn pilots if friction is building to the point of failure.

In 2001, Kaydon Corp., the Michigan-based company that supplied Sikorsky with the swashplate, admitted in federal court that employees falsified inspection records while testing the parts. Although denying it was to blame for any crashes, the company agreed to pay surviving family members an undisclosed amount, according to court records.

A 2005 lawsuit against Sikorsky also resulted in payouts to the families of fallen crew members. Frank Fleming, a New York aviation lawyer and former Marine helicopter pilot, filed the case on behalf of four sailors killed when their Sea Dragon caught fire and crashed in southern Italy.

The blaze started in the aircraft’s No. 2 engine, which Fleming argued was a recurring problem Sikorsky had learned about and ignored more than a decade earlier. Sikorsky denied the allegation. It settled the case out of court.

After researching the case, Fleming said he wouldn’t rule out flying in a Sea Dragon. But he might hesitate.

“Safety is a broad and flexible concept,” he said.

Overall, he thinks the helicopter he flew in Vietnam, a Sea Dragon predecessor, was safer.

By the time Fleming won a settlement for his clients, the Navy had begun to rework the plans to retire its mine-clearing workhorse.


During the first Gulf War, the Navy’s fleet of Sea Dragons found and destroyed dozens of underwater mines. Two decades later, mine warfare remains high on the service’s list of strategic priorities.

In 2011, when Iran threatened to choke off the Strait of Hormuz with submerged mines, the Navy sent two additional Sea Dragons to Bahrain, doubling the number it keeps in the region. The following year, the helicopters played a central role in a massive international mine hunting exercise in the strait, which serves as main supply channel for much of the world’s oil.

There are other ways to clear mines – the Navy has used everything from surface ships to specially trained dolphins – but airborne mine-hunters offer a special set of capabilities.

The Sea Dragon – the only military helicopter specifically designed to clear mines – can respond more rapidly to threats and sweep faster and closer to the shore than surface ships. Dragging a sled from above also helps keep sailors out of harm’s way.

But keeping the maintenance-intensive Sea Dragons flying doesn’t come cheap. In the late 1990s, top brass began planning to replace the Sea Dragon with a more flexible and cost-effective option: the MH-60S Seahawk. The Navy envisioned equipping the smaller and far less powerful helicopter with a special mine-clearing kit and planned to begin        deploying them on aircraft carriers and amphibious assault ships in 2005.

That never happened, and the Sea Dragon retirement was pushed back.

Around 2007, the Navy said it would instead deploy the mine-hunting Seahawk aboard its new fleet of littoral combat ships, envisioned as a fast-moving mothership for mine-hunting helicopters and a host of unmanned underwater vehicles.

But last year, the Pentagon’s Director of Operational Test and Evaluation announced that the MH-60S was not powerful enough to tow the minesweeping and sonar equipment, forcing the Navy to scrap the plan.

And so the Sea Dragons fly on with no concrete plan for when the program will end.

After the crash last month, Flannery told reporters he had no concerns about the long-term safety of the helicopter.

“The Navy is taking appropriate steps to ensure the viability of the MH-53E until its services are no longer required,” Flannery wrote in an email this week.

Bill Arnold, a retired Navy captain, was among the first pilots to flythe Sea Dragon and served as the commanding officer at HM-14 in 1989. Back then, the Navy was still building new Sea Dragons, the program was well-funded and morale was high, Arnold said.

For the past decade, the community has operated under a cloud of uncertainty.

“I can tell you that once the Navy has decided an aircraft is going away, they quit putting money into it and quit putting emphasis in it,” Arnold said. “That has a big impact. You tell a community you’re going away, where do you think the best pilots are going to go?”

Another change that affected the community: As the Navy prepared to wind down the program, the service consolidated its five HM squadrons to just two and placed them under the command of air wings that include several other types of helicopters.

Sea Dragon aircrewmen – the enlisted sailors who operate the mine-clearing equipment – used to spend multiple tours at various HM squadrons spread across the country, and were trained to maintain their own aircraft, Arnold said. Since consolidation, Arnold said most aircrewmen spend one tour working on Sea Dragons before transferring to        another airframe.

“We used to have an entire wing that was all aerial mine countermeasures,” Arnold said. “Then you lose that identity and that backing, and soon the culture suffers for it.”

About the reporting: This story is based on numerous sources, including archived newspaper articles, federal court records, information from the Naval Safety Center, Naval Air Systems Command, Naval Air Force Atlantic, as well as interviews with Navy officials, former pilots and aircraft maintainers.

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