Geekzone: technology news, blogs, forums
Guest
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.




16910 posts

Uber Geek
+1 received by user: 4758

Trusted
Lifetime subscriber

Topic # 225415 17-Nov-2017 17:00
Send private message

I keep meaning to ask someone. Almost always when I fly, which I have done a lot over the years and happened on my flight from CHCH last night, the plane feel like it surges forward for a few seconds, and the engines make a lot of noise. Mid flight or sometimes right before they are landing, on final approach. Doesn't seem long enough to make a material difference to not being fast enough for approach etc.

 

 

 

Was wondering if anyone else noticed and knows why?

 

 


Create new topic
5479 posts

Uber Geek
+1 received by user: 240

Trusted
Geekzone
Lifetime subscriber

  Reply # 1903353 17-Nov-2017 17:00
Send private message

Allow me to introduce you folks to our new travel community: TravelTalk NZ.

 

We hope to see you there!

 





I am the Geekzone Robot and I am here to help. I am from the Internet. I do not interact. Do not expect other replies from me.



3261 posts

Uber Geek
+1 received by user: 531

Lifetime subscriber

  Reply # 1903364 17-Nov-2017 17:25
Send private message

An A320 by any chance?
If the requested speed and the actual speed are too far apart or are diverging, the auto-thrust system aggressively applies power to recover. Effectively 'revving up' and then slowing again. This may happen when the change is as little as 10km/h so as soon as the increase is felt, it is over.
In cruising flight it may be due to the areoplane being asked to speed up by air traffic control. On approach, it may be due to the aircraft reaching its approach speed for its particular configuration of flaps and landing gear. The engines 'rev up' to maintain that speed. In a Boeing the throttles move under the control of the auto throttle system and can be overpowered by the pilots, so they can reduce the movement if it isn't appropriate. In the Airbus the levers do not move with auto thrust changes and so it is more difficult for the pilots to prevent the surge.




Areas of Geek interest: Home Theatre, HTPC, Android Tablets & Phones, iProducts.

 
 
 
 


Try Wrike: fast, easy, and efficient project collaboration software
2549 posts

Uber Geek
+1 received by user: 265


  Reply # 1903370 17-Nov-2017 17:41
Send private message

Also to compensate for the airspeed decrease and flaps being on high attack


2308 posts

Uber Geek
+1 received by user: 1121


  Reply # 1903617 18-Nov-2017 11:28
Send private message

Your sense of motion is not to be trusted when in an aircraft. For example, you shouldn't feel any lateral movement when you're turning. The floor of the aircraft will still feel "down" but if you look out the window the horizon will move up or down. Similarly, slowing down may actually feel like you're dropping, even though the aircraft is flying straight & level. So you may not actually be surging forward. More likely, the nose of the aircraft is pitching up slightly, so that gravity becomes slightly aft of what you believe to be "down". You perceive this as a forward acceleration because the seatback presses against your back a little more.

 

The objective is to be descending at a specific rate whilst maintaining a specific airspeed *and* being on a line that leads to the right touchdown point on the runway. It's a complex juggling act where airspeed, aircraft nose up/down pitch, thrust, lift, and drag all interact, so changing one setting affects multiple things. In addition there's wind speed, which varies with altitude and gusts. So the pilot (human or robot) is continually adjusting thrust and pitch to maintain the desired profile.

 

 

Probably what's happening is that a little extra gust of headwind or a downdraft is pushing the aircraft below/behind the glideslope line. The pilot (perhaps a robot, perhaps human) responds by advancing the throttles and pulling back a little on the stick. Increasing power alone would move back to the glideslope, but increase airspeed. Pulling back on the stick alone would move the aircraft towards the glideslope, but at the cost of a decrease in airspeed. So, if airspeed is right, you need to do both.

 

You feel the stick-pull/pitch-up as a "surge in speed", and hear the engine noise increase.

 

 


Mad Scientist
18257 posts

Uber Geek
+1 received by user: 2312

Trusted
Lifetime subscriber

  Reply # 1903653 18-Nov-2017 12:54
Send private message

It's to adjust the plane's speed and altitude. You don't want to touch the ground a hundred metres too short or too long. It's not a helicopter that can come down vertically if you overshoot or go up vertically if you undershoot, it's a diagonal line that cannot be too steep (impact too hard) or too shallow (too fast).

844 posts

Ultimate Geek
+1 received by user: 115


  Reply # 1903658 18-Nov-2017 13:21
One person supports this post
Send private message

Batman: It's to adjust the plane's speed and altitude. You don't want to touch the ground a hundred metres too short or too long. It's not a helicopter that can come down vertically if you overshoot or go up vertically if you undershoot, it's a diagonal line that cannot be too steep (impact too hard) or too shallow (too fast).

 

 

 

Really?

 

 

 

 


11176 posts

Uber Geek
+1 received by user: 3542

Trusted
Subscriber

  Reply # 1904012 19-Nov-2017 13:14
Send private message

Batman: It's to adjust the plane's speed and altitude. You don't want to touch the ground a hundred metres too short or too long. It's not a helicopter that can come down vertically if you overshoot or go up vertically if you undershoot, it's a diagonal line that cannot be too steep (impact too hard) or too shallow (too fast).

 

 

 

Pull Up! Pull Up! Too Low! Too Low! Terrain! Terrain! Pull Up!






11939 posts

Uber Geek
+1 received by user: 2075

Trusted

  Reply # 1904016 19-Nov-2017 13:27
Send private message

Speed brakes. This are applied to slow the aircraft, when they are retracted, it feels like a surge forward.All to attain the correct air speed on approach. Not used that often but if the wind conditions are variable and the aiircraft doesnt bleed knots as expected, a quick way to adjust the speed  


Create new topic



Twitter »

Follow us to receive Twitter updates when new discussions are posted in our forums:



Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:



Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:





News »

Exhibition to showcase digital artwork from across the globe
Posted 23-May-2018 16:44


Auckland tops list of most vulnerable cities in a zombie apocalypse
Posted 23-May-2018 12:52


ASB first bank in New Zealand to step out with Garmin Pay
Posted 23-May-2018 00:10


Umbrellar becomes Microsoft Cloud Solution Provider
Posted 22-May-2018 15:43


Three New Zealand projects shortlisted in IDC Asia Pacific Smart Cities Awards
Posted 22-May-2018 15:14


UpStarters - the New Zealand tech and innovation story
Posted 21-May-2018 09:55


Lightbox updates platform with new streaming options
Posted 17-May-2018 13:09


Norton Core router launches with high-performance, IoT security in New Zealand
Posted 16-May-2018 02:00


D-Link ANZ launches new 4G LTE Dual SIM M2M VPN Router
Posted 15-May-2018 19:30


New Panasonic LUMIX FT7 ideal for outdoor: waterproof, dustproof
Posted 15-May-2018 19:17


Ryanair Goes All-In on AWS
Posted 15-May-2018 19:14


Te Papa and EQC Minecraft Mod shakes up earthquake education
Posted 15-May-2018 19:12


Framing Facebook: It’s not about technology
Posted 14-May-2018 16:02


Vocus works with NZ Police and telcos to stop scam calls
Posted 12-May-2018 11:12


Vista Group signs Aeon Entertainment, largest cinema chain in Japan
Posted 11-May-2018 21:41



Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.



Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.