What is AI173?
AI173 is the flight number for Air India’s non-stop service from New Delhi (DEL) to San Francisco (SFO). Air India is the flag carrier of India and a member of the Star Alliance. Air India operates AI173 three times a week, on Mondays, Wednesdays, and Fridays, using Boeing 777-200LR aircraft. AI173 is one of the longest flights in the world, with a distance of about 12,400 km and a duration of about 15 hours.
What makes AI173 unique?
AI173 is unique because it is one of the few flights that crosses the International Date Line (IDL), which is an imaginary line that runs from the North Pole to the South Pole and marks the boundary between two consecutive calendar dates. The IDL is located mostly along the 180-degree meridian of longitude, but it deviates slightly to avoid dividing some countries or islands.
AI173 crosses the IDL from west to east, which means that it travels from a later date to an earlier date. For example, if AI173 departs from New Delhi on Monday at 4:00 AM local time, it will arrive in San Francisco on Monday at 7:00 AM local time, even though it has flown for 15 hours. In other words, AI173 gains a whole day by crossing the IDL.
Why does AI173 cross the IDL?
AI173 crosses the IDL because it follows a route that takes advantage of the tailwinds from the jet stream, which is a fast-moving air current that flows from west to east in the upper atmosphere. By flying with the tailwinds, AI173 can reduce its fuel consumption, carbon emissions, and flight time. AI173 also avoids flying over Pakistan and Afghanistan, which are considered as conflict zones and require higher altitudes and longer routes.
AI173’s route changes depending on the season and the weather conditions. In winter, AI173 flies over China, Japan, and the Pacific Ocean before crossing the IDL and reaching San Francisco. In summer, AI173 flies over Kazakhstan, Russia, and Alaska before crossing the IDL and reaching San Francisco.
Conclusion
AI173 is the flight number for Air India’s non-stop service from New Delhi to San Francisco. AI173 is unique because it crosses the International Date Line from west to east, which means that it travels from a later date to an earlier date. AI173 crosses the International Date Line because it follows a route that takes advantage of the tailwinds from the jet stream, which reduces its fuel consumption, carbon emissions, and flight time. AI173’s route changes depending on the season and the weather conditions.
