Ask the Captain: Nose up or down? It depends
Question: When an aircraft is descending toward landing, it seems some planes fly down nose pointed downward, and some seem to float down with the nose pointed up. Is this true, and if so, why the difference?
— Submitted by reader Herb Brockert, Holliston, Mass.
Answer: When configured for landing, the position of the nose is determined by whether there are leading edge slats installed. Airplanes with leading edge slats (movable panels on the front of the wing) approach the runway with the nose up, while airplanes without slats approach with the nose down. Examples of the former include the Boeing 737, while the Bombardier CRJ-200 approaches nose down (later-model CRJs have slats).
Good question.
Q: When on final approach, am I correct in stating that the nose is slightly up, throttle at around 70%? If so, what makes the aircraft descend?
— Pete, Seattle
A: In a jet with slats, the nose is slightly above the horizon, and the power is set to give the proper descent rate. When the slats and flaps are extended, the nose being above the horizon does not result in a climb unless the thrust (power) is set to a high setting.
The simple answer to your question is that the weight of the airplane exceeds the lift being produced, consequently the airplane descends.
Q: I had a flight that was supposed to land in San Diego but got diverted to Palm Springs. On approach, the nose of the plane was pointed down, and the plane was going much faster than any plane I've ever seen on an approach to a runway, and I have flown a lot. I was worried that the plane was about to run out of fuel. What do you think may have been happening?
— Pam, San Diego
A: Fuel requirements are carefully calculated before departure. This includes fuel to divert to another airport, then additional reserve fuel. It is very unlikely that there was a fuel consideration.
In the case of your flight, it is more likely the pilots were higher than the normal descent path and corrected for it.
Q: Your recent column “That sinking feeling right after takeoff" had a lot of great information, but I'm wondering if the answer might be incomplete. Doesn't the transfer of the plane's weight from the wheels to the wings also contribute to that feeling?
— Jim in ABQ
A: No, the lift produced by the wings overtraining the wheels is more gradual and is G positive, making you feel like you are being pushed into your seat. The flap retraction causes a net lift loss for a brief time and a reduction in G force, making you feel like the airplane is sinking.
John Cox is a retired airline captain with US Airways and runs his own aviation safety consulting company, Safety Operating Systems.