Rubrica mensile pubblicata on-board sui voli UA; si puo' sempre imparare qualcosa no? 
Captain Mike Bowers is chief pilot at our Newark Liberty International Airport (EWR) hub. This United Hub series is based on our column in Hemispheres magazine, in which Mike answers questions from our customers. This issue’s Q&A focuses on questions about what happens while an aircraft is landing.
Q: On landings, how do you determine whether 'full' flaps are required or not?
A: Flaps are the rear part of the wings that extend and lower during takeoff and landing. It allows us to temporarily change the shape of the wing to develop more lift so we can take off and land slower. The front of the wing has similar devices called slats or leading edge flaps. Generally speaking we land with full flaps so we can touch down at the slowest speed. On takeoff we use a lesser flap setting to accelerate and climb quickly because any additional amount of flaps create drag which would reduce our climb performance. Once airborne we retract the flaps to allow for minimum drag and rely on the higher speed of the air over the wing to create the lift required.
Q: Near the end of a flight sometimes I can tell the plane is decelerating well before the pilot makes the landing announcement. When a plane decelerates - what does that usually mean with respect to how far we are from landing - distance and time-wise?
A: The time and distance varies at different airports based on the amount of other traffic in the area, specifically from other airports near your destination airport. Typically we start our descent from altitude about 120 miles from the airport. That is when you sense the engine power being reduced. The time also varies because we may be required by the air traffic controllers to fly at a lower airspeed to maintain our separation at busy airports. For most airports 20 – 30 minutes is what you can expect.
Captain Mike Bowers is chief pilot at our Newark Liberty International Airport (EWR) hub. This United Hub series is based on our column in Hemispheres magazine, in which Mike answers questions from our customers. This issue’s Q&A focuses on questions about what happens while an aircraft is landing.
Q: On landings, how do you determine whether 'full' flaps are required or not?
A: Flaps are the rear part of the wings that extend and lower during takeoff and landing. It allows us to temporarily change the shape of the wing to develop more lift so we can take off and land slower. The front of the wing has similar devices called slats or leading edge flaps. Generally speaking we land with full flaps so we can touch down at the slowest speed. On takeoff we use a lesser flap setting to accelerate and climb quickly because any additional amount of flaps create drag which would reduce our climb performance. Once airborne we retract the flaps to allow for minimum drag and rely on the higher speed of the air over the wing to create the lift required.
Q: Near the end of a flight sometimes I can tell the plane is decelerating well before the pilot makes the landing announcement. When a plane decelerates - what does that usually mean with respect to how far we are from landing - distance and time-wise?
A: The time and distance varies at different airports based on the amount of other traffic in the area, specifically from other airports near your destination airport. Typically we start our descent from altitude about 120 miles from the airport. That is when you sense the engine power being reduced. The time also varies because we may be required by the air traffic controllers to fly at a lower airspeed to maintain our separation at busy airports. For most airports 20 – 30 minutes is what you can expect.