US Airlines No Longer Operate the Boeing 747 (arstechnica.com)

An anonymous reader quotes a report from Ars Technica: On Wednesday, Delta Airlines flight 9771 flew from Atlanta to Pinal Airpark in Arizona. It wasn't a full flight -- just 48 people on board. But it was a milestone -- and not just for the two people who got married mid-flight -- for it marked the very last flight of a Boeing 747 being operated by a U.S. airline. Delta's last scheduled passenger service with the jumbo was actually late in December, at which point it conducted a farewell tour and then some charter flights. But as of today, after 51 long years in service, if you want to ride a 747 you'll need to be traveling abroad.Ars Technica recalls the history of the Boeing 747 in its report, mentioning that although no U.S. passenger carriers still operate the big bird, several hundred remain in service with other airlines around the world.

Comments

Re:747 not the Only One

[known_coward_69]

Not even the 787. Soon the 727 or 737 along with the baby airbus planes will have long range engines capable of long distance flight. Used to be you needed a 747 to go from NYC to Rome or London. Now it's your average tiny plane with hourly or several flights a day which can be rescheduled if not enough tickets are sold.

Re:That's nice, I guess

[Luckyo]

Literally, nothing. It's not that the aircraft is outdated. It's that it's very concept of large, heavy, four engine aircraft is outdated in civilian use.

Large four engined aircraft are significantly more expensive to operate compared to two-engined variants, while having much higher requirements of the airfield, making their potential flight destination list much smaller. Their primary advantage actually had to do with certain regulatory framework, which requires aircraft flying over oceans to have certain amount of flight time on minus one engine (i.e. case of engine failure). Essentially they are required to be always in range of an acceptable airfield if one engine dies. Modern twin engined aircraft like A350 and 787 have incredibly high range on one engine, meaning they are cheaper to operate on the same route while being acceptably reliable for regulatory agencies.

Add to this the fact that primary model of civilian aviation due to this change has largely shifted from hub model (large hub with large long range aircraft, from which small aircraft service nearby smaller airfields as connection flights) to point to point model (smaller twin engined aircraft are economical to operate directly to said small airfields, bypassing the hubs entirely) and you see why age of jumbo jets is slowly passing. It's not just that they are being replaced by other aircraft on the same routes. It's that route structure itself is changing.

Re:747 not the Only One

[AK Marc]

Funny how unrelated things change everything.

Computers changed the hub model. Before computers, linking 3 hops for hundreds of people was impossible. So if you flew everyone into a hub at 11 a.m., then out of the hub at 1 p.m., you had a 2 hour window, and could get anyone from anywhere to everywhere.

With early computers, you could have more flights, and more complex connections. Today, with more powerful computers, you optimize passengers, not routes, and we learn that mesh routes are best, and the demand/sales is analyzed to predict where to put planes to minimize costs for a passenger (remember, a old hub style required two flight, unless you lived in, or were flying to, a hub). Also, as you fly mesh routes, you cut travel time, which increases demand.

Hub makes sense for flying from US to Europe, where you fly JFK to Heathrow, But within a market, hubs are dying.

Re:That's nice, I guess

[Solandri]

That's mostly correct. 2 engines are more efficient than 4 engines (for the same amount of total thrust). That's why the 777 beat the A340 into a bloody pulp in the market, and why the airlines demanded Airbus redesign the A350 when it was first proposed. Airbus tried to make it a 787 competitor, but the airlines really wanted a 777 competitor, so convinced Airbus to make the A350 larger (only the largest capacity 787 matches the smallest capacity A350). Likewise, 1 engine is more efficient than 2 (leaving me to wonder if in the future, airliners will operate on a single engine during cruise, with the second engine used only for takeoff and as a backup).

However, back in the 1960s and 1970s when the 747 was introduced, there were some other factors favoring 4 engines.

• This was pre-Arab oil embargo. Fuel didn't cost as much, so fuel efficiency wasn't as high a priority.
• Engine design hadn't progressed to the point where you could generate enough thrust for such a large plane with just 2 engines. Heck, the DC-8 and 707 (introduced just a decade before the 747) were 4-engined planes despite having the passenger capacity of a modern 737 or A320. And the much smaller 727 was three engines. The big technological leap was the transition from a turbojet to a turbofan. A turbojet relies on throwing the exhaust gases backward at high velocity to generate thrust. A turbofan uses part of the exhaust gases to spin a ducted fan blade which pushes non-exhaust air backward to generate thrust. Basically the same thing as a turboprop (a propeller driven by a jet engine, instead of a piston engine), except the propeller is ducted. IIRC, nowadays close to 90% of the thrust comes from the bypass fans, only about 10% from the exhaust jet.
• In older days, many airport facilities weren't as modernized. A plane which suffered an engine failure might not be able to have it repaired at the destination. It would have to fly with the failed engine back to an airport with a modern repair facility. You can't do that with a twin-engine plane without violating safety regulations, but you can with a 4-engine plane. Pilots of the DC-10 and L1011 (tri-jets) would frequently leave the #2 engine (located up in the tail) running at certain airports which didn't have the facilities to jump-start that engine if the built-in starter failed. Nowadays, most airports even in developing countries are modernized enough to maintain and repair most engines, at least well enough for the plane to fly to a better repair facility on two engines.
• Older airport runways weren't as luxuriously long as at modern airports. In the event a plane has a reject (abort) a takeoff due to an engine failure, a twin engine plane only has 50% of its thrust available for reversing and slowing the plane down. A 4-engine plane has 75% of its thrust available for slowing down, so can safely take off on a shorter runway.
• As you mention, ETOPS, or how far a twin-engine plane could safely fly with one failed engine, didn't exist back then. It was simply considered too dangerous to fly a twin-engine passenger plane out past its glide range over the sea.