The Big Sky
Sitting in the windowless control room at Boston Center, we were isolated from the outside world. We'd focus on our tasks for up to two hours, and then routinely be relieved by another controller so we could leave the room. It was then that we could take a short break, and walk outside to get a breath of fresh air. Sitting in an airliner seat, with few if any breaks for fourteen, fifteen, or even eighteen hours takes isolation from the outside world to a new level!
Soon after the Millennium, we began seeing what I called "long ranger", or ultra-long endurance airline flights at Boston Center. They'd depart from a New York metro airport, travelling through our sectors to exotic destinations such as Mumbai, Singapore, and Hong Kong. Heavy with fuel, they'd request an initial altitude lower than most other eastbound international flights, because they were just too heavy with their required fuel to operate like the flights destined to Europe (less than half of the distance and time en route). Due to their weight, their rate of climb was slower than most European-bound jetliners too. Another operational item to remember was that after their long trip, there was little leeway with altering their route of flight, as their tight fuel reserves allowed for few amendments. Here's a little bit of history of long-ranged flights.
Currently, the longest scheduled airline flight in the world connects Singapore's Changi International Airport with Newark's Liberty International. As scheduled, it takes the Singapore Airlines Airbus A340-500 jetliner a few minutes shy of nineteen hours to complete the trip of 8,280 Nautical Miles (NM). The airliner carries maximum fuel, at the expense of about one third of its possible passenger and cargo capacity. There's obviously extra flight crew members aboard to handle the "flight time restrictions" placed upon the operator too. There are a few factors that can make the trip a bit longer or shorter, including polar weather... that's right, polar weather. Upper wind patterns dictate what route an ultra-long range flight will file. Sometimes, the most efficient route of flight from Liberty International to Changi is following a Great Circle route via the North Pole. My simplistic explanation of the reason for polar travel is this: the aircraft pretty much flies north and then south, and lets the earth, which is travelling "eastbound", to spin under the airplane and allow it to travel westward without really heading in a westerly direction. If the winds were right, the flight would depart Newark and fly over Albany and Plattsburg NY, then over Montreal in Canada before turning slightly northeastbound until it was near the North Pole. It would then turn southbound and overfly central Russia before arriving in the western Pacific area.
With any long-range flight, the jetstream winds can play havoc with a schedule. Upper winds are generally stronger in the winter than in the summer in the Northern Hemisphere, and normally travel from west to east. On a long-endurance flight near the North Pole between Newark and Changi, the headwinds can easily add two extra hours of flying time in one direction when compared to the reverse trip. Polar weather contains other hazards too. Radiation exposure from the sun is much higher near the North Pole and there have been instances where flights have deviated from their preferred tracks to avoid areas that were affected by strong solar flare activity. Radiation is a health risk for humans, and can wreak havoc with sensitive electronics in navigation and communication equipment. Another problem with polar routes is severe cold... colder air temperatures than systems can handle. A result of super low temperatures is that trace water found in jet fuel forms ice crystals that can clog fuel line filters, causing an engine to shut down in flight.
Some of today's longest-ranged airliners include the four-engined Airbus A340-500, and Boeing's new 747-8 Intercontinental, as well as Boeing's twin-engined 777-200LR (LR for "Longer Ranged"). There are trade-offs with passenger seating, cargo capacity, and fuel carried when talking about the longest duration each aircraft can fly, so it is difficult to compare specifics. Generally speaking, the ultra long range Boeing 777-200LR and Airbus A340-500 can exceed 9,300 NM each. Boeing's new 747-8 Intercontinental can fly some 8000 NM, while the 787-800 twin can fly up to 8,200 miles non-stop. The massive Airbus A380-800 has a published range of 8,300 NM. What do these numbers mean? Fourteen to fifteen hour flights can "comfortably" be flown in any one of these jets, and the ultra-long seventeen to nineteen hour flights are possible with the noted Boeing 777 and Airbus 340 versions. Interestingly, a Boeing 777-200LR on a test flight established a non-stop endurance record of 11,664 NM over 22 hours and 42 minutes in 2005, but of course the jet was mainly empty except for a handful of people and plenty of fuel.
Long ranged airliner flights aren't something new; Zepplin airships flying between Germany and South America had an endurance of over 100 hours aloft, but never needed anywhere near that time to cross the Atlantic during the 1930s. Propliner ultra-long ranged flights include a pre-World War II Lufthansa FW-200 Condor flight of over 24 hours between New York and Berlin, and TWA's L-1649 Starliner (a Lockheed Constellation version) trip of slightly more than 23 hours over the North Pole between London and San Francisco. During World War II, Australia's Qantas operated a Consolidated PBY flight that varied between twenty eight and thirty three hours that covered over 4000 non-stop miles. The aptly named journey was called "The Double Sunrise" flight between Australia and Sri Lanka and was accomplished more than 200 times between 1943 and 1945.
Commercial airliners aren't the only ones with extraordinary endurance. The Gulfstream G550 corporate jet has a range of 6750 NM, the newer G650 anticipates 7000 NM. Bombardier's Global Express XRS boasts a range of 6325 NM. Both Boeing and Airbus have converted airliner airframes into business jets too; Boeing's BBJ1, a 737 variant, can fly 6200 NM, and Airbus's A-319ACJ can travel 6517 NM with a somewhat similar load. Of course, with air refueling a standard feature in many military aircraft today, many transports and bombers are limited by the endurance of their crews, not fuel capacity.
Apart from the slower rates of climb and odd routing (why go "north" when your destination is in the Southern Hemisphere?), these long ranger flights operated like any other aircraft. One thing in the back of my mind was that the pilots you spoke with on your frequency were either in for a long trip sitting in their seat, or were getting close to their destination after a very long trip. I was sure thankful that I could look forward to a quick stretch and a breath of fresh air in an hour or so, not half a day.
By Ken Kula