69

Very little to go on (non-pilots are lousy at classifying turbulence) but my best guess is that you experienced moderate turbulence. If it was severe, your description would have been something more like this: I couldn't focus my eyes to see. Someone who wasn't belted down was flung violently against the ceiling, then slammed to the floor. The ...


62

Turbulence is reported on a scale of light, moderate, severe, and extreme. The full definitions are available in the FAA Aeronautical Information Manual. As experienced in the cabin, For Light Turbulence, "Occupants may feel a slight strain against belts or shoulder straps. Unsecured objects may be displaced slightly. Food service may be conducted and ...


50

I agree with @Simon that, given your description, you were in moderate turbulence, and as such you were not at risk. You mentioned that the flight attendants looked terrified, which implies that you were able to see their faces, which might mean they were up and about? If so, you were not in severe turbulence. In severe turbulence the flight attendants are ...


37

There are a few ways that pilots are aware of potentially turbulent areas. Eyesight The most obvious way is just by looking outside and observing the sky. Large billowing clouds, called cumulus clouds, indicated pockets of unstable air (the clouds are rising because the air under them is as well). If the pilots must fly through these clouds then its a ...


28

The cabin is rigidly attached to the fuselage, with bolts. But in a way the cabins do have suspension: from the wings riding on air. Elasticity of the wing construction material acts like a spring. Load it with a vertical gust, and it will bend upwards, then spring back. The wing bending experiences damping forces from the surrounding air, proportional to ...


26

Most of the time the turbulence we experience is termed "chop", which is akin to what you experience on a boat on the lake -- bumps but no real altitude deviations. With altitude deviations we'll call it "turbulence". Within these broad categories we'll qualify them with "light", "moderate", "severe" and "extreme" in reports to ATC and other aircraft. ...


26

Turbulence can be quantitatively expressed as Eddy Dissipation Rate (EDR). EDR can be calculated from available onboard measurements, however it is not yet common for aircraft to have software to calculate the EDR. Originally it was thought to have EDR reported over ADS-B, but it did not become a part of the current specifications. It might be in the next ...


23

In a word, it's called "Turbulence" and in cloud, it is caused by differing air density. Sciencey bit: The sun warms the earth and causes the air to rise. As warm air rises, it cools at the wet adiabatic lapse rate. Inside of a cloud, this rate is much slower than outside of it. Clouds are more dense than dry air, and the water vapour inside a cloud is not ...


23

It's very likely that the 787 would have less problems with turbulence than the DC-8 did. The wings of the Boeing 787 are more flexible than the DC-8, and that flexibility will damp the immediate impact of turbulence. More important, the Boeing 787 has a gust alleviation system that reacts to turbulence by counteracting the induced accelerations using the ...


22

Turbulence is described using the following qualitative descriptions [Source]: Informally, you can use a g-meter to quantify turbulence, at least in the up-down direction, but I don't know of any particular values that equate to various types of turbulence


21

Air turbulence is very much the same as the currents of a river. When a parcel or stream of air moves differently than the area around it, you get turbulence as you transition between them. An example would be if you are outside on a windy day but stand behind a tree to "get out of the wind". If you step out from behind the tree, you will feel a sudden "...


19

In the US it is an offence under federal law. A loose 180lb/80kg projectile inside an aircraft is a threat to other passengers during turbulence, in the worst cases of passenger misbehaviour cabin staff can and have forcibly restrained passengers and/or diverted to a nearby airport to have the passenger deplaned and sometimes arrested. Seven Ways to Get ...


19

What is turbulence? Turbulence is random and stochastic Each realization of a turbulent flow is unique and fluctuations in velocity are very irregular in space and time. dissipative Turbulence cannot maintain itself and will decay into laminar flow without energy input from the environment (e.g. mean shear in the velocity field or buoyancy). Reducing ...


13

Some large aircraft (maybe all?) have a minimum and maximum turbulence penetration speed. For the 747-100 and -200 aircraft the minimum was 270 knots and the maximum 320 knots IAS. I forget the mach equivalents. Those same aircraft had a turbulence mode on the autopilot that reduced the sensitivity to pitch and roll deviations. However, many pilots (...


13

You're correct that the structure may induce separation under some conditions. However, the effects are unlikely to be significant given the (publicly) available data on the concept. From the available images, the deck is quite small, with a seating capacity of only two. Image from gizmag.com Also, it is located at some distance in front of the vertical ...


12

Turbulence can be caused by a variety of different weather patterns. The one you describe in TX as "an area of dense clouds and lightning so thick that there was no visibility outside the windows" is probably a thunderstorm. Inside the cockpit, the pilot has a weather radar system that tells her instantaneously where the densest area of precipitation is, ...


12

Lift is created by accelerating air downwards. The same goes for wake turbulence: The vortices form at the boundary between the downward-moving strip of air (wake) from surrounding air that tries to fill the void left by the wake. Friction will eventually dissipate the kinetic energy of the wake, but in case of heavy aircraft the motion will continue for ...


12

I looked up the flight on Flightradar24.com. The descent starts at 16:10 UTC and ends at 16:29 UTC, going from 38.000 feet to 24.000 feet. So, the aircraft descended 14.000 feet in 19 minutes. 14.000 divided by 19 makes roughly 750 feet per minute, which is a relatively normal descent rate for airliners. The cause for this is probably an ATC instruction. ...


10

When I was in training, we had specific explanations on the effects of the different levels of turbulence. Light turbulence: Pilot's point of view: Turbulence that momentarily causes slight erratic changes in altitude and/or attitude (pitch, roll and yaw). Passenger's point of view: Occupants may feel a slight strain against seat belts or shoulder straps. ...


10

The answer you are referring to explains how radar is used to fly through a squall line whilst avoiding the most turbulent areas. Conventional weather radar cannot detect wind speed or turbulence directly, it only detects solid and liquid objects above a threshold size. The most turbulent areas of thunderstorms are also those areas that contain the most ...


10

@PeterKampf's answer is (as usual) perfectly fine in and of itself. I would add another way to look at it, more focused on the vortices you were interested in. One way of looking at the airflow is to imagine it is simply made of two opposite vortices. Here is how it starts: the downash created by the wing provokes the creation of two wingtip vortices, easy ...


10

Before jumping to conclusions, let's look at the numbers: The duration was about 10 seconds, the altitude excursions was 500 ft. There is no way we can derive a 15g acceleration from that. It could have been, for example, a 3g acceleration over 2 seconds, resulting in 200 feet excursion, followed by 0.2 seconds coasting after which the pilots levelled ...


9

The elasticity of the fuselage does indeed dampen the load factors from gusts somewhat. Therefore, gust-induced accelerations are a little higher over the wing than in the forward or rear fuselage. If the gust causes a pitching motion, this creates its own accelerations which adds to the bumps from the vertical accelerations. Elevator deflections cause ...


9

The short answer is that radar cannot directly observe the wind. What radar can detect is the velocities of small particles lofted into the air. This is done by measuring the doppler shift of the energy returned to the radar. The radar can only detect the component of velocity toward or away from the radar. The radar doesn't have to diagnose turbulence ...


8

At night time and with a broken radar.... The above mentioned methods are good but the ability to plan ahead and perhaps even give you that brief whilst we are on the ground is due to the fact that we always carry the latest Significant Weather (SIGWX) charts that cover our route. Here's what one looks like (view in new tab): You can find a legend for ...


8

TL;DR clouds and a Doppler radar in the nose registering uneven air. If the plane flies into clouds then there will get some turbulence because at the boundary the air will change, especially in thunderclouds. Clear air turbulence is more devious as it happen in clear air (like it says in the name), these are detected by instruments on the plane like a ...


8

The cross-wind limit is 35-40 knots for most aircraft with gusts allowed to perhaps 45 or so. The head-wind limit is slightly higher, but not much. Knot is nautical mile per hour. Nautical mile is 1.852 km, that is 1.15 mile (and for those who prefer metric, knot is just a bit over ½ m/s). So wind more than 40 miles/hour may interrupt airport operations and ...


8

China is well known for having very strict air traffic control, who often are reluctant to give pilots the flexibility to deviate around bad weather or try a different - smoother - flight level (as I've experienced first-hand). That can lead to aircraft in Chinese airspace encountering more turbulence than in other parts of the world. Secondary to that, ...


8

I cross that pass on my commute twice a week in my VariEze at altitudes between 5500 and 11500 ft depending on winds and clouds. There's nothing to be particularly nervous about, there's rarely any noticeable turbulence if you're at 7500 or higher. You can check the Sandberg AWOS and forecast winds aloft, and ask L.A. Center or Bakersfield Approach for ride ...


7

Turbulence affects aircraft in the same way whether it is banked or not. The difference however would be the end result of the turbulence. For example, if an aircraft were to encounter turbulence strong enough to roll the aircraft 20 degrees to the right, the end results would be a 20 degree bank if starting from level, but 45 degrees of bank if they ...


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