You take a Philippine Airlines non-stop flight from Manila to Los Angeles on board a Boeing 777-300ER. You depart Manila and arrive in Los Angeles according to schedule and you noticed the trip duration was 12 hours. However, on your return flight from Los Angeles to Manila using the same aircraft (B777-300ER), you noticed that the flight duration was 15 hours and 30 mins? I shall now explain why PAL flights from Manila to US are shorter (in terms of flying time) than the other way around.
The flight utilized the same aircraft type (B777-300ER), didn’t stop anywhere, and just flew from Los Angeles to Manila without any diversions. Why was the Eastbound flight 3 hours shorter than the westbound flight?
The same thing goes for Manila to New York flights. Utilizing an Airbus A350-900, PR126 Manila to New York takes 15 hours and 33 minutes. PR127 from New York to Manila utilizing the same aircraft takes 16 hours and 50 minutes!
These do not only happen in PAL Manila – US flights but on all flights around the world as well.
The reason why PAL westbound flights, the US to Manila, take longer than eastbound (Manila to the US) is due to the rotation of the Earth.
How the Earth’s rotation affects travel time
The Earth rotates on its axis at about 0.0005mph, but at the surface of ang Equator, the rotational velocity is about 1,040 from West to East. The Earth only rotates in one direction and that is West to East. It may seem like an aircraft moving from East to West should take shorter than that moving West to East since the Earth’s rotation is like “pulling” the destination closer. This is not the case though. There are other factors.
Not only does the surface rotate, but the atmosphere also goes with it as well. This influences the wind patterns above the Earth, also known as high-altitude jet streams.
A rotating object has a force perpendicular to the axis of rotation known as the Coriolis force. This force pushes winds to the east in the northern hemisphere and the west in the southern hemisphere. The strength of this force is relative to the surface speed rotation of the Earth.
The winds are also affected by solar heating which flows from areas of high pressure to low pressure. Combined, these effects produce jet streams that move from west to east, but with a bouncing pattern. The jet stream can vary in strength, altitude, and routing over time and which are usually strongest when closer to the poles.
Jet streams
Airlines study the jet stream patterns every day for which they decide which routes to take. If an airplane flying from Manila to the US over the Pacific Ocean can piggyback on a strong tailwind moving Eastward, it will take that route even if they would have to fly a long physical distance. Flying with the jet stream not only allows for faster flight duration but also saves on fuel. The time difference is indeed huge. However, the US to Manila (Westward) flight paints a different picture as it flies against the jet stream. This takes more fuel and longer flying time, hence, airlines constantly look for a route to avoid some of the effects of this jet stream.
Below is a comparison of two PAL flights, PR102 and 103. PR102 flew from Manila to Los Angeles and the other is PR103 which flew from Los Angeles to Manila.
Both utilized the same Boeing 777-300ER aircraft on January 20 but PR102’s flight time was 11 hours 24 minutes whereas PR103 took 14 hours and 52 minutes. Notice that the Eastbound flight from Manila to the United States flew closer to the pole whereas the Westbound flight from the United States to Manila flew closer to the equator. PR102 flew along with the jet stream whereas PR103 flew against the jet stream moving westward.
Stopover at Guam
Before the Boeing 777-300ER came into service with the airline, PAL used the classic Boeing 747-400 to fly the same route. The trip from Manila to the US was non-stop even at full load. The trip back to Manila however was different. There are times the flight would have to make stopovers in Guam to refuel and sometimes, none. PR103 during that time would depart Los Angeles from around 7:00 pm to 8:00 pm which include a stopover at Guam before landing in Manila. If PR103 would be delayed until 10:00 pm or so Los Angeles time, there is a huge chance that the 747-400 would not be making a refueling stop in Guam as the route to be taken would not encounter strong tailwinds.
Again, this does not only go for PAL flights but for all flights around the world, regardless of which country, route, and destination. Some were just wondering why PAL flights from Manila to the United States were shorter in terms of flight time as compared to the return flight.
First love never dies. I fell in love with airplanes and aviation when I was a kid. My dream was to become a pilot, but destiny led me to another path: to be an aviation digital media content creator and a small business owner. My passion for aviation inspires me to bring you quality content through my website and social accounts. Aviation is indeed in my blood and blog!
