The Longest Flight With No Alternate Airports Requires Perfect Fuel Calculations

Making sure the fuel supplies are more than adequate is crucial when flying the longest route in the world with no alternate landing site.

Say you’re driving on an Interstate, probably somewhere in the Western United States where there are long stretches of highway and nothing else.

You notice the fuel warning light come on and you wonder where and how far to the nearest gas station. As you worry about running out of fuel, one thing you know – you’re safe on the ground, even if the engine coughs to death after exhausting the final fumes.

Now transfer the low fuel scenario to an airplane flying from the West Coast to Hawaii. That’s the longest stretch – nearly 2,500 miles – for a plane with no alternate landing options. Nothing but the blue sky above and the bluer Pacific below.

Even with commercial airlines moving to twin-engine aircraft, flying extended distances such has the mainland to Hawaii remains safe. Aviation rules call for aircraft and flights to be ready for emergencies if one of the engines becomes disabled. Running out of fuel with nothing but water for 360 degrees is not acceptable.

In April this year, a United Airlines flight bound for Honolulu from San Francisco had to pull a U-turn two hours into the flight. Stronger than expected headwinds influenced the pilots to make an overly cautious – and smart – decision to not risk a disaster.

“When the headwinds are greater than what were expected, and are going to be sustained for four or five hours of flight, you’re simply not going to be able to land with your legal minimum of fuel,” ABC aviation expert John Nance said. “It doesn’t mean you’re going to run out, but it means you’re not going to be legal. That’s when you have to turn around.”

Safety rules require commercial flights to have enough fuel to reach the intended destination, hold for 30 minutes and then have another 45 minutes of fuel to land at alternate airport. (If you’ve been on a flight diverted from your original destination, you know the drill.)

In 1989, a Trans World Airlines jumbo jet developed a fuel leak on a flight to Hawaii. The leak was discovered when it was too late to turn back. Instead of landing in Honolulu, the plane made it safely to the closest airport – Hilo International Airport on the island of Hawaii. The plane reportedly had four minutes of fuel remaining when its wheels hit the tarmac.

Check out this historical account of the harrowing and heroic early days of attempts to fly from the West Coast to Hawaii.