Turbulence is experienced to varying degrees on just about all flights. Below is an example of what to expect and an explanation of what is actually happening and how pilots react.
I was once on a flight over Africa where there was a lengthy delay before take-off owing to thunderstorms over the airport. We encountered a further huge storm en route to our destination, and despite diverting around it, we experienced severe turbulence.
Boisterous drunks on board quietened up before becoming quite ill, and in addition to the seat-belt lights being kept on the whole way, the cabin crew were ordered to their seats by the captain.
Initially it was quite fun, but the fun stopped after a short while. It was definitely a white-knuckle roller-coaster ride.
Turbulence gives one the impression that the aircraft is flying out of control, but it is not. The aircraft may feel as if it is going to come apart. Again, it will not do that.
Pilots try to avoid turbulence, largely for the sake of the passengers. Cargo planes regularly fly through turbulence that passenger planes avoid, and they do not fall out of the air.
As uncomfortable as it was, the plane was never in any danger. Not even if it had been struck by lightning, which commercial aircraft are designed to be able to cope with. Your plane will almost always be under control of the autopilot when going through turbulence. The autopilot has a special setting for turbulence in which it makes fewer, and more gentle corrections. This relies on the tendency for aircraft to self-correct from most random flight changes resulting from air movements.
As with anything else, turbulence varies in extent and intensity. There is a four-point scale for it:
- Light. You can feel it, but you can walk around okay and the seatbelt lights remain off.
- Moderate. It is still possible to walk and the cabin crew continue their duties but the seatbelt lights are put on.
- Severe. What I experienced in my tropical flight above. It is unusual. Cabin crew are commanded to their seats.
- Extreme. This is very rare because of all of the precautions taken to avoid it.
So, what are the real dangers associated with turbulence?
1. Loss of altitude when you are close to the ground. If you are close to the ground and you get pushed down, the plane could hit the ground. Thunderstorms can cause this and aircraft will not take off when a storm cloud is over the airport. The pilot may divert the flight to a different airport to ensure safety, or the plane may be put into a holding pattern in a safe part of the sky until the weather in the region of the landing field has improved.
2. Gusts near the ground. One pilot I spoke to told of a landing at Schipol when the plane was hit by a gust of wind just as he lined up the plane with the runway in a side-wind. The jet’s wings rotated several degrees in a second and it was all he could do to level the wings and slam it on the ground. Fortunately it was a cargo flight, so there were no complaints. Passenger flights are typically diverted to another city if there are strong side-winds at the destination.
Aircraft and airports are both equipped to detect wind shear conditions that could otherwise be of danger to the plane.
3. Injury. Passengers who are not belted in can be thrown against the roof of the cabin. Persons have in fact died or have been seriously injured, particularly when flying in “clear air” with the seatbelt lights off when unexpected turbulence has been encountered. Loose objects such as the drinks trolley can be flung against you, causing injury; and luggage can shift in the overhead lockers and spring the lock, dropping items on you. The best you can do to protect yourself against this is to keep your seatbelt on for the whole flight.
4. Structural failure. Over the years a disturbing number of light planes, not equipped with weather radar and with only basic instruments (flying according to Visual Flight Rules) have come to a bad end through falling apart in bad weather. Commercial operators are better equipped and will reroute or reschedule if the weather outlook is poor. The planes are also, as the cost would suggest, stronger and more reliable than private aircraft. And the pilots are much less inclined to take unnecessary risks.
All things said, turbulence can be extremely uncomfortable but it is very rarely a source of real danger.