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Plane Answers: Route planning, shunning reverse-thrust and side-sticks
Welcome to Gadling's feature, Plane Answers, where our resident airline pilot, Kent Wien, answers your questions about everything from takeoff to touchdown and beyond. Have a question of your own? Ask away!Vivian asks:
Hi Kent,
I enjoy your column very much and I have a pretty basic question. How exactly is a route for a particular flight planned? I recently flew ORD-DEL and we went to the North Pole and then due south through Asia. Wouldn't a route through the Atlantic and over the middle east be a more direct route?
Believe it or not, flying from Chicago to Delhi will normally take you very close to the North Pole. Imagine using a piece of yarn over a globe to trace the route.
But an easier method is to go to this site and put in the three-letter codes yourself to see the great circle route depicted. Here's the ORD-DEL example:
These routes, which are often made up of waypoints every few hundred miles, change every day to take advantage of the winds. Our dispatchers look at the shortest "wind distance" which they will usually use, subject to ATC approval. To fly over the pole, crews have to have special training and the airline has to be approved for this kind of flying.
These flight plans are filed with the FAA a few hours before the departure, so it is possible for the winds or weather to change the eventual route of flight.
Alex asks:
Hi Kent,
I was on a 757 about a year ago and I noticed that when we landed at our destination the thrust reversers weren't used. I asked for a seat close to an engine because I like to see the thrust reversers deploy but it didn't happen that day.
I thought that maybe there was something wrong with an engine but the flight crew didn't mention anything so I lingered around the gate to see if a maintenance truck would pull up to the plane but that didn't happen either.
Someone told me that maybe it had something to do with noise abatement, but it was about 5 or 6pm.
Can you think of any other reason why the thrust reversers may not have been used?
Hi Alex,
Great question.
There are a few airports–Manchester, England comes to mind–that restrict the use of thrust reversers early in the morning or late at night.
But I suspect that wasn't the case on your flight. I'll let you in on a little secret.
Occasionally, if a pilot touches down early enough on the runway and the point at which we plan to exit is a ways down field, we'll consider NOT using any reverse thrust. Usually, however, we'll do this by opening the reverser blocker doors, but not adding thrust to stop the aircraft.
Why, you ask?
Because we're vain. Passengers tend to think it was a smoother landing if we avoid following up a nice touchdown with the noise and shake associated with the reverse thrust.
So there you go. Vanity!
Marius asks:
Does it take a lot of force to advance the throttles and yoke or can you hardly feel them at all?
And would you prefer a sidestick to yoke?
The throttles on the 767 are rather stiff. Most of the other Boeing aircraft have throttles that move back and forth rather smoothly, with little or no resistance.
Each airplane has a different 'feel' on the yoke (control wheel). Some are rather heavy, like the 757, and some are light, such as the A300.
The A320 and later Airbuses have a side-mounted stick. I can't tell you what it's like to fly this type of stick, since I've only flown Boeings and the MD-80, but I really would like to give it a try.
One interesting thing about the Airbus side sticks; they aren't interconnected between the captain and the co-pilot. So when you move one side stick, the other one doesn't move.
If the captain pushes full down and the co-pilot pulls full back, the inputs cancel each other out.
The yokes on Boeing aircraft move together, so it does give you an idea what the other guy is doing when they're flying.
Do you have a question about something related to the pointy end of an airplane? Ask Kent and maybe he'll use it for next Friday's Plane Answers feature.
Filed under: Plane Answers
Reader Comments (Page 1 of 1)
VP Oct 17th 2008 7:58PM
Thank Kent for taking time out of our busy schedules to answer my question in such great detail. Maybe i can catch one of your flights sooner rather than later. Too bad your airline doesn't have a big presence here in ATL.
Bob Oct 18th 2008 5:16AM
"Because we're vain. Passengers tend to think it was a smoother landing if we avoid following up a nice touchdown with the noise and shake associated with the reverse thrust."
LOL!
Greetz Bob - http://www.torrentbug.com
gail Oct 19th 2008 9:37PM
I asked my pilot boyfriend SFO Mike is he ever indulged his vanity by not using reverse thrusters. He told me his airline prohibits it! NOT because they wouldln't like their pilots to show off now and then in the name of passenger satisfaction; reverse thrusters save heat on the brakes.
Chuck Sweet Oct 3rd 2009 11:17PM
Hi Kent--I worked for PNA and Western in Anchorage(1964 till 1983),and remember Wien air very well.I was so sorry to see the day Wien went out of business,and Reeve air as well.I just discovered your articles today,and am so glad I happened across them.Was Noel Wien your grandfather,or great grandfather?I never met him,but Merle K."Mudhole" Smith of Cordova airlines,and Bob Reeve sure wakens some fond memories.I am enjoying your writings very much,so keep up the good work Sir.
D2D Nov 9th 2008 12:57AM
Vanity can play a part, and sometimes, reversers are just not necessary. Landing on a 11 or 12 thousand foot runway, with an exit planned at the end means if you use the reversers and don't disarm the autobrake, ATC may require you to exit the runway since you'll be at a walking pace half-way down the runway and thus potentially obstructing traffic behind you.
Or, if you land on the north runways in Vancouver (YVR), noise abatement requires minimal use of reverse, regardless of time of day.
The third option is that they didn't work on that particular aircraft on that particular flight. Thrust reversers are generally not required to stop the aircraft, and performance charts often do not consider the stopping power that reversers provide in their calculations. Just reversers may provide "bonus" stopping power. So if the reversers don't work for some reason, the aircraft can still be dispatched safely.
Gail is right though too, TRs save brakes. Autobrakes target a specific speed reduction in feet per second per second, so if the reversers are providing speed reduction, the brakes will not need to work as hard.
Kent Wien Nov 9th 2008 12:59AM
Well said, D2D. Thanks for adding some more detail to my answer.