President Roosevelt called December 7, 1941 a “date that will live in infamy,” an apt description . Over 2,500 people were killed, another thousand were wounded and the Pacific naval fleet was crippled. For the crew of one Pan American flight, the attack forced them to do what hadn’t been done before: Fly a commercial flight around the world.

The plane was a flying boat, registration NC18602 and called California Clipper before being renamed Pacific Clipper. At 106-feet-long and with a wingspan of 152-feet, it was one of the largest aircraft of its day. a crew of 10 transporting up to 74 passengers.

had an advantage in the early decades of aviation. Runway infrastructure back then was still developing. And in wartime, runways could be bombed out. For flying boats, so long as you had a body of water you had a runway. Flying boats also often had greater range than land-based aircraft, making them better for crossing oceans.

On December 7, NC18602 was headed to Auckland, New Zealand after having left San Francisco six days before. Onboard was a crew of 10 with 12 passengers. Auckland was supposed to be the final leg of the trip before returning to base, the Pan Am Historical Foundation.

In the morning hours the radio delivered a message informing the crew that Pearl Harbor had been attacked. The crew was instructed to implement Plan A.

The Captain was veteran Pan American pilot Bob Ford, and he knew exactly what to do, the Washington Post. He pulled a sealed envelope from his jacket. Inside were instructions that the crew was not to let the advanced aircraft fall into enemy hands.

Once the plane touched down in Auckland and the passengers disembarked, the crew faced a challenge. They were instructed to strip the plane of identifying marks, then fly west. Their destination: New York City.

They would have no help and radio silence along the way. Ford secured $500 ($8,922 in today’s money), and that would be all of their cash for the trip. They didn’t have charts and instead navigated using an atlas and by the stars.

The Washington Post a number of the flying boat’s landings. Java was short on aviation fuel, so the flying boat’s reserve tanks were filled with auto gas. Ford used the avgas for departure, then switched to the auto gas at altitude, letting the engines run hotter. Just before landing in what is now Sri Lanka, the Boeing 314 even encountered a submarine, Washington Post:

The Homeric odyssey continued as the plane flew on to Ceylon, now Sri Lanka. Just before landing there, Ford eased his plane below the clouds — only to discover an enemy vessel about 300 feet below him.

“All of a sudden there it was, right in front of us, a submarine!” Ford later recalled. “We could see the crew running for the deck gun.” He quickly pulled back into the clouds and avoided the incoming enemy fire.

And when the Pacific Clipper left Ceylon, the number three engine failed, requiring the crew to turn back, conduct repairs, then try again the next day.

The crew were also warned not to fly over Arabia, the Pan Am Historical Foundation , but they did it anyway. Luckily, Pacific Clipper flew over cloud cover for several hours. When cloud cover did break, the plane was right over the mosque at Mecca, where overflights were banned. Ford recalled seeing people running out and presumably firing at the aircraft. But if they were, they didn’t have anti-aircraft guns.

Getting from Congo to Brazil was a test of endurance for the aircraft and its crew. It required a nonstop 20-hour, 3,583-mile flight across the Atlantic. It was a flight that set a record for longest non-stop flight in Pan Am history.

When all was said and done, NC18602 had flown 209 hours and traveled 31,500 miles. The flying boat made 18 stops over 12 different nations and visited all but two of the world’s continents. In getting home safely, the crew also set records, including the first round-the-world commercial flight and longest continuous commercial flight.