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More than 70 years after the giant airship went down off the coast of California, a research expedition captures ghostly images of genius from a bygone era.

Sitting inside Western Flyer’s command center three miles off the California coast, you’d never know you were at sea on a research vessel. The room is eerily dark, lit only by the glow of 18 video monitors and computer screens, and bone-chillingly cold to prevent the computer equipment from overheating. Ten of us are bundled into this black box, eagerly awaiting the first video feed from the ocean bottom 1,500 feet below, but so far we’ve seen nothing.

It’s the second day of a weeklong archeological expedition to survey and map the underwater wreck site of USS Macon, the largest aircraft ever built by the United States and the last dirigible ever flown under our flag. Macon crashed three miles off the Big Sur coast in February 1935 following a catastrophic structural failure resulting from a slapdash repair job and a brief but severe rain squall. A powerful gust of wind sheared off the airship’s dorsal fin, puncturing two of its 12 helium gas cells and buckling frame No. 17.5 in the tail section.

It took nearly 45 minutes for Macon to succumb to its wounds as the officers and crew fought desperately to maintain flying trim. When the accident first occurred, the crew dumped every bit of ballast they could find in order to raise the tail section. Then, realizing they’d overcompensated, they vented precious helium as the dirigible yo-yoed from 1,000 to 5,000 feet (near its operational limit), and back.

Eighty-one of the dirigible’s 83 officers and crew survived the plunge and were soon rescued by Pacific Fleet ships. But by then Macon had settled on the stormy ocean surface, collapsed, begun breaking up and sunk. Despite two fatalities, it was a happier ending for Macon’s crew than the crew of its sister ship, Akron, experienced. Akron crashed off the New Jersey coast in 1933, killing 73 of its 76 officers and crew. Ironically, one of two who survived, Lt. Cmdr. Herbert V. Wiley, would become captain of the similarly ill-fated Macon.

Macon lay undiscovered on the ocean bottom for 55 years before the U.S. Navy and Chris Grech, deputy director of marine operations at the Monterey Bay Aquarium Research Institute (MBARI), discovered it in 1990. No one has spent more time exploring the Macon wreck than Grech, who is one of the expedition’s coprincipal investigators.

Small and compact, Grech looks as if he were born to squeeze through the hatch of a tight-fitting submersible, something he has done on more than one occasion. He sits glued to his video monitor watching the descent of Tiburon, Flyer’s remotely operated vehicle (ROV). “This is one of the more significant wrecks on the West Coast,” Grech says. “From an aviation standpoint, it’s quite a time capsule.”

More than half the expedition team is squeezed into Tiburon’s command center, sitting in two rows of high-backed captain’s chairs. The first row is opposite the control deck and occupied by a rotating assortment of ROV pilots; Grech; Ericka Burton, a marine biologist; and Stephen Rock, a professor at Stanford University and director of its Aerospace Robotics Lab.

The second row behind them includes two other co-principal investigators, Bruce Terrell, senior archeologist for the National Oceanic and Atmospheric Administration (NOAA); and Robert Schwemmer, who heads up NOAA’s Maritime Heritage Program for the West Coast. Rock’s graduate student and assorted members of NOAA and MBARI fill out the team.

“This is the first archeological survey conducted in NOAA’s Monterey Bay sanctuary,” Schwemmer says. “The advanced cameras and computer imaging…[will] allow us to better survey and document the Macon’s historic wreckage.”

In an unusual public/private collaboration, a government agency (NOAA) and a private research institute funded by the Packard Foundation and dedicated to advanced research in ocean science and technology (MBARI) have partnered with Stanford University to survey and map Macon’s two principal debris fields. The majority of the expedition will be spent testing a new Stanford software program developed by Rock and his graduate students that will provide the first high-definition photo mosaic of Macon’s wreck site, including its four Curtiss F9C-2 Sparrowhawk fighter planes that sank along with the dirigible and now lie somewhere below us.

“Stanford’s new imaging control system has huge potential,” says Grech. “It’s quite a technical achievement to obtain a large aerial view of a spot underwater.”

Schwemmer and Terrell are along because they hope to use the expedition and Stanford’s photo mosaic to gather enough data to recommend Macon be added to the National Register of Historic Places. Both Schwemmer and Terrell are old hands at this. Schwemmer was part of the NOAA team that recovered USS Monitor, a Civil War ironclad that sank off the coast of North Carolina, and Terrell has been chasing shipwrecks for NOAA for many years.

Macon’s strategic role was to serve as the “eyes of the fleet,” searching for enemy ships across wide sections of ocean and reporting their location. To aid in that role, Macon also functioned as a flying aircraft carrier capable of launching and retrieving five Sparrowhawks from its belly hangar.

As we wait for the first high-definition images of the wreck to reach us from the ocean floor, we can see the water is dark but rich with life. Ocean detritus flies by Tiburon’s cameras, and it looks as if we’re driving in a snowstorm until a curious fish decides to inspect a headlight, does a head plant and dashes off into the darkness.

The three co-principal investigators, Grech, Terrell and Schwemmer, have been up since 6 a.m. overseeing the predive check and then watching and waiting as MBARI’s custom-built robotic explorer, Tiburon, is lowered through the retractable doors of Flyer’s moon pool. The moon pool is situated center ship, and provides easy and protected access to the ocean below.

“It’s an awesome feeling,” Grech says about the opportunity to revisit the Macon wreck site. “All the work trying to find it over the years has finally paid off.”

Western Flyer is a SWATH (small waterplane area twin hull) ship, which means it’s designed like a catamaran with two large pontoons sunk deep in the water. The pontoons make the ship ride high and provide an exceptionally stable platform for ROV dives. Staring at Tiburon’s umbilical cord as it slowly unspools into the moon pool, one is impressed with the technology a well-funded operation like MBARI can bring to bear on a project like this.

It takes about 30 minutes for Tiburon to reach the ocean bottom, and we’ve been sitting patiently for 15. Outside Flyer, the day is filled with brilliant California sunshine, but inside the control room we might as well be locked in a submarine for all the cold and darkness we’ve been subjected to.

It’s hard to appreciate from pictures alone just how large USS Macon was. The giant airship weighed 120 tons, was 146 feet tall and had a diameter of 133 feet. Perhaps the most telling statistic about Macon, though, was its length: 785 feet, longer than three 747s parked nose to tail and just a few feet short of the ocean liner Titanic.

At a total construction cost of $2.5 million, Macon, designated ZRS-5, was the most expensive aircraft built in its day. A rigid lighter-than-air dirigible built by the Goodyear-Zeppelin Corporation of Akron, Ohio, Macon had a light but strong skeletal structure made of duralumin supporting its treated cotton cloth skin. Photographs of the airship under construction make it appear as if it were assembled from a giant erector set.

Macon carried eight internal German-made Maybach VL-II engines, four on each side. Each VL-II delivered up to 560 hp via a 16-foot drive shaft to a propeller mounted on an outrigger. The internal engines made it possible to swivel the propellers in a 90- degree arc, and they were reversible. As a result, the Maybachs could generate both forward and reverse thrust as well as vertical thrust for upward or downward movement.

Another of Macon’s novel features was its ability to recycle water from engine exhaust using condensers. The airship needed the extra water for ballast to help compensate for the weight loss that occurred as a result of fuel consumption.

Like any aircraft carrier, Macon was a self-contained world. Located portside amidships were the crew’s washroom, seven bunk rooms with four bunks each and a small smoking compartment. The officers’ wardroom and two staterooms (with four bunks each) as well as the galley and mess rooms were on the starboard side. The captain had his own cabin right above the control car in the forward part of the airship. All of Macon’s rooms were heated, a necessary luxury given its cruising altitude.

Macon was kept aloft by helium, which is safer than hydrogen because it doesn’t burn. But helium was also scarcer than hydrogen and therefore considerably more expensive. In 1933 there was only one source for helium in the United States, a small plant in Texas, so airships sometimes cannibalized each other’s helium supply to stay operational.

Macon was the Navy’s fourth dirigible in its Lighter Than Air (LTA) program. It was preceded by USS Shenandoah, launched in 1923; USS Los Angeles, launched in 1924; and USS Akron, which first flew in 1931 and crashed just one month after Macon’s April 1933 christening.

The Akron crash resulted in aviation’s greatest death toll up to that time and raised significant doubts about the expense and efficacy of the Navy’s LTA program both within the Navy and in Congress. Especially devastating was the death of Rear Adm. William A. Moffett, Navy chief of aeronautics. Moffett had been an early champion of airships and was a driving force behind the Navy’s LTA program. Without the respected admiral’s protection, LTA critics began to circle.

Of the LTA program’s four dirigibles only one, Los Angeles, was not a victim of catastrophic structural failure. But when Macon completed its initial shakedown period at Lakehurst Naval Air Station in New Jersey and was sent west to Sunnyvale NAS in California, there was still hope that the LTA program would prove successful.

Though similar to Akron in almost every detail, Macon had several significant advantages. First, it was 8,000 pounds lighter and 3 knots faster. Macon’s engine radiators were placed inside the airship to streamline it instead of mounted outside as on Akron. And because strut girders obstructed two aircraft hangar positions in Akron, it could only carry three Sparrowhawks compared to Macon’s five.

This is not Grech’s first return to the Macon wreck site since its discovery. He’s been back at least half a dozen times over the past 16 years. However, this will be his longest, most thorough examination of the wreck as well as the first time he’s ever mapped the site using high-definition digital photography, which promises a better way to record and measure the debris field’s decay.

“I’m very concerned about the wreck’s deterioration,” Grech says. “I’ve noticed a lot of it in the airship’s metal structures. In 15 years there’s a layer that’s just gone away.”

People have always known the general vicinity of Macon’s crash site, but its exact location had been a mystery. “We’d made a couple of unsuccessful trips looking for it,” Grech recalls. “But that’s the nature of the beast.”

The mystery didn’t clear up until Commander Wiley’s daughter, Marie, happened to be visiting the Monterey coast on a bird-watching expedition and by chance had lunch at Balesteri’s Moss Landing Restaurant, where she noticed a piece of Macon’s duralumin frame mounted on a wall plaque. Needless to say, her lunch was fortuitous.

“I just happened to see it,” Marie Wiley, now Marie Ross and 75 years of age, recalls, “and of course I immediately recognized it.”

Word quickly spread of Wiley Ross’ discovery and soon reached Grech, who had been searching for Macon on and off since 1988. Grech visited the restaurant’s owners and persuaded them to reveal where the wreckage had come from. The trail led to retired fisherman David Canepa, who had pulled up the wreckage while fishing off Big Sur. At first Canepa was reluctant to give up the location of his prized fishing spot. Nevertheless, Grech coaxed the Loran coordinates out of him, and when the U.S. Navy offered Grech a ride aboard its Sea Cliff submersible, he soon found the coordinates were indeed accurate. After years of searching, Grech found Macon in a matter of minutes.

Marie Wiley was only 4l⁄2 years old when Macon went down, but she still remembers the airship and attributes her fear of heights to running on its catwalks as a child. Her elder brother, a retired naval officer, also has childhood memories of their father stopping Macon over his house and dropping his hat on the front lawn to let them know he would soon be home.

A lot has changed about the wreck since Grech first saw it. Storms have moved large pieces around, and sediment is burying Macon’s skeletal structure (the airship’s skin has long since deteriorated). Nevertheless, many features are still recognizable.

“We don’t have a shipwreck,” says Grech, “we have an airship wreck that’s flattened out…there’s much to be investigated here [but] you have to get underneath the layers. What’s buried tends to be well preserved.”

Though Grech and his co-principal investigators are here to survey and photograph the site, they also hope to locate Macon’s control car and tail section, which have never been found. They could be in an undiscovered debris field or buried in sediment beneath the midsection. Or they could be lost in one of the many deep underwater canyons that line this part of the Monterey coastline. The wreck site has two major debris fields, but recent side-scan sonar imaging suggests there may be a third debris field still unexplored as well as several “points of interest” that Grech and the team want to investigate.

Like most naval ships, Macon had a redundant command-and-control system. The control car was near the bow and housed the rudder and elevator controls, the altimeter and airspeed indicators, the rise and fall indicators and an engine order telegraph system that enabled the captain to relay commands to the engine room. Divided into three compartments, the control car had a bumper on its underside to soften landings and a staircase that lowered from its rear compartment (where a defensive machine gun installation was also located) to permit officers a quick exit upon landing. A second control cabin, located in the lower stabilizing fin at the ship’s tail, was a backup. However, the stern went down first on Macon, and nobody has seen its tail section in more than 70 years.

The LED readout on the control panel nears 1,500 feet when Grech coolly announces he has Macon wreckage on his screen. Immediately, all heads in the room crane to see what Grech is seeing. There, illuminated by Tiburon’s blazing lights, is a large section of duralumin girder lying on its side on the ocean floor. Next to it, a tangle of cables snakes off into the darkness. Tiburon hovers in place for a few minutes and then begins moving methodically across the ocean bottom in a grid pattern. It’s not long until we see our first clearly recognizable piece of wreckage, a giant Maybach engine with its drive shaft in place and what could still be remnants of its Allison gearbox.

The atmosphere in the control room is calm and professional, but an unmistakable thread of electricity runs just beneath the surface. The big, burly ROV pilot sits relaxed at his station, casually palming Tiburon’s control stick as if it were a video game device. On the monitors Tiburon slowly hovers over the ocean floor while Grech illuminates the Maybach engine with two red laser dots and takes a reading.

The morning is spent grazing through debris field B. Macon’s girders lay helter skelter across the bottom, but we locate several more Maybachs and what looks like the galley stove before we hit pay dirt: the four Curtiss Sparrowhawks.

Amazingly, all four biplanes sit upright on the bottom, wings and tails intact, their distinctive yellow paint scheme and red, white and blue Navy stars clearly visible on their topmost wing. Two even sit nose to nose as if they’d decided to have a quick tête-à-tête before taxiing for takeoff. Grech and the others plan to make a close inspection of the Sparrowhawks over the next couple of days to see if they can identify each plane from its individual color scheme.

As we zoom in for a closer look, there’s no mistaking their giant skyhooks, the big metal catch mechanism welded to their topmost wing. These were designed to snag Macon’s trapeze in mid-flight so the Sparrowhawk could be hoisted inside the hangar in the airship’s belly. None of the Navy’s two flying aircraft carriers ever lost a plane, which was a better record than the sea-based carriers could claim, though the Sparrowhawks also had an optional tail hook for carrier landings.

The Sparrowhawks’ aluminum frames have kept the fighters in pretty good shape, though some of their wings have gaping holes where the yellow fabric has deteriorated. Although Macon could carry five Sparrowhawks (one suspended on the trapeze), it normally operated with four aircraft, and there were four on board the day of the crash. Records indicate that the crew tried to jettison the aircraft but were unsuccessful, so they went down with the airship.

“The fact that they were landing airplanes on airships during the 1930s blows me away,” Grech says shaking his head. “It’s a very unique period in aviation history, and there’s a lot of people who don’t know anything about it.”

The ocean bottom is lousy with fish. Red and white thornyheads, sablefish and Pacific hake swim lazily across our view screen, and one fish is even nestled in the open cockpit of a Sparrowhawk. We can also see the marine-encrusted instrument panel in one Sparrowhawk as well as another’s flying stick. Most still have their engines, but the propellers appear to be missing and there’s no sign of the twin .30-caliber Browning machine guns housed in their engine cowlings, though the gunsight on one plane is clearly visible.

Macon’s primary role was as a scout ship, and the Sparrowhawks were initially intended to be used as defensive weapons to protect it from attack. But after Macon was repeatedly “shot down” during fleet exercises it became clear to Commander Wiley that the dirigible should stay safely hidden in the clouds and let the Sparrowhawks do the scouting. Perhaps the greatest achievement of Macon’s more than 50 flights was when it managed to survey 172,000 square miles of ocean during one 36-hour operation, an impossible feat for a destroyer.

We’ve left the Sparrowhawks for the time being and moved into another part of the debris field. Over the next couple of days Grech will conduct a guided tour of the ship’s galley, parts of its officers quarters, an aluminum chair, a metal cabinet, a table and a set of drawers that look like they could have once held navigation charts. Some parts of the airship are more recognizable than others, but it is still thrilling to glide silently over the great ship’s bones and figure out what went where.

We return to the Sparrowhawks repeatedly and eventually locate five of the eight Maybach engines as well as Macon’s mooring receptacle. Numerous fuel tanks, which were thrown overboard during the crash to lighten the airship, litter both debris fields and have imploded from the ocean pressure.

The Macon crash was determined by a naval court of inquiry to be the result of inadequate repairs to the airframe following a previous structural failure over Texas. Commander Wiley was cleared of any blame, and it was suggested that the Navy’s Bureau of Aeronautics had rushed Macon into service to counter mounting criticism and demonstrate the effectiveness of its LTA program.

It should come as no surprise that Commander Wiley had made his fair share of enemies trying to prove Macon’s strategic value. For instance, some Navy higher-ups wanted Wiley court-martialed for “misapplied initiative” after Macon surprised President Franklin Roosevelt aboard the light cruiser USS Houston. Roosevelt was in the middle of the Pacific traveling from Panama to Hawaii and was not expecting to find any U.S. naval aircraft so far from home. But that was exactly the point Wiley wanted to make.

A Sparrowhawk was dispatched to drop two waterproof mail packages for the president. Unfortunately, both packages missed the deck of Houston and landed in the ocean, but that did not stop Roosevelt from cabling, “Well Done…Fine Performance and Excellent Navigation.” Ironically, Houston was one of the ships that rescued Macon crewmen after its fatal crash less than a year later.

The death of Macon spelled an end to the Navy’s LTA program. Though it would continue experimenting with blimps until 1962, the Navy never built another rigid airship.

After five days exploring the ocean bottom, Grech is finished as well and reels Tiburon aboard Western Flyer. The expedition has achieved everything it had hoped to, including identifying each Sparrowhawk based on its personalized color scheme, though there is still no sign of Macon’s control car or stern section.

Stanford University’s photo mosaic software has performed flawlessly, and the expedition now has gigabytes of digital data mapping every inch of Macon’s known debris fields. The expedition’s high-definition photo mosaic will help scientists better understand the airship’s debris dispersal and the rate of the site’s deterioration, key steps to eventually preserving the wreck.

As Flyer heads north, it’s clear this won’t be Grech’s last trip to the airship wreck. The expedition has been successful, but there is more to learn about the last giant that ruled our skies. When the NOAA and MBARI teams finish analyzing the data, Grech is confident there will be at least a dozen good reasons to return. “I’m really an optimist that we’ll be back,” he says, adding that he hopes the expedition will spawn a lot of interest and initiative both among the public and in government circles.

In the meantime, Macon’s final resting place remains a well-guarded secret to prevent treasure hunters and salvagers from picking the wreck over.“There are no other airships like this,” Grech says admiringly.“It’s the last intact airship wreck in the world.” He wants to preserve the old girl’s dignity, even in death.

After seeing her for the first time, you’d have to agree.


John Geoghegan is a director of the SILOE Research Institute in Marin County, Calif. For further reading, he recommends The Airships Akron & Macon: Flying Aircraft Carriers of the United States Navy, by Richard K. Smith.

Originally published in the May 2007 issue of Aviation History. To subscribe, click here