Weather
Good weather? Bad weather? What does it mean? How do I know it’s safe? A captain may announce that the weather at the destination airport is good or bad. This oversimplification, for public consumption, can lead to misunderstanding and completely unnecessary concern. Whenever there’s an accident, reporters can be counted on to say weather may have been the cause. Disregard what they say. Reporters know very little about the relationship between weather and safety. With a more sophisticated understanding, every concern you have about the relationship between weather and safety can be allayed.
Bad Weather
I’m afraid of bad weather and I start checking it days before my flight.
If you were to overhear a conversation about weather between pilots, dispatchers, and weathermen, you might never hear the term “bad weather.” Instead, you would hear them say the weather is above minimums (legal to takeoff or land) or below minimums (not legal to takeoff or land). Take a tip from pilots. Forget about good and bad weather. If it’s legal to fly, it’s safe to fly. Bumpy? That’s safe, too. Bumps just make it harder to keep the flight out of mind.
How do you know if weather is above or below legal minimums? It is simply a matter of measurement. Weather is measured every few minutes at every airport. The measurements are published immediately and are available within seconds to the dispatchers who plan the flights, to the pilots who confirm the planning of the flight, and to pilots in the air. To take off or to land, the measurements must meet or exceed the criteria legally required by the FAA (or the equivalent authority in other countries).
A licensed dispatcher plans the flight. The captain reviews the plan with the dispatcher. To determine whether the flight can legally be flown, they study the weather at the departure airport, en route, and at the arrival airport. If it is possible for the ceiling or visibility at the destination airport to be lower than legally required for landing, one or more alternate airports at which the weather will be unquestionably satisfactory must be specified in the flight-planning documents. Of course, if the flight is landing in an hour or two, these forecasts are pretty reliable. But if the flight is landing in eighteen hours, well, everyone knows, weather is changeable. That’s why alternate airports are plotted into the flight plan.
These planning documents are signed and attested to both by the captain and the dispatcher. Both must certify that the planning is complete and that the flight can be conducted safely. Adequate fuel must be loaded on the plane to fly to the destination airport: This includes 10 percent extra to compensate for greater than forecast headwinds, plus fuel for an approach to the runway, plus fuel to then divert to an alternate airport, plus fuel to stay in a holding pattern, if that is called for, for a minimum of a half hour, plus fuel for landing.
For takeoff, visibility—the distance the pilot can see ahead of the plane—must be adequate for steering the plane down the runway. Most runways have lights at the edges and a white line down the middle of the runway, as well as centerline lights. Centerline lights are a row of lights imbedded in the runway on the white line to guide the plane down the runway in fog. The visibility required for takeoff depends upon whether or not the runway has these features. Transmissometers installed alongside the runway measure the visibility. Takeoff is not permitted if visibility is less than required or if water or snow on the runway is in excess of specified limits.
For landing, there must be sufficient visibility and ceiling. Ceiling is the distance between the runway and the clouds above it. Typically, the visibility must be one-quarter mile or more (that’s more than 1,300 feet), and the ceiling two hundred feet or greater. However, with advanced equipment, landings can be made when visibility and ceiling are lower.
Measurements of wind speed and direction are constantly available. Headwind helps a plane take off or land by reducing the length of runway needed. Except in extreme weather, high wind velocity is not restrictive if landings or takeoffs can be made directly into the wind. Whatever wind Mother Nature provides is that much less speed that needs to be produced by the engines. At any point during the flight, the pilots can use a device in the cockpit to obtain, within seconds, current weather information for any airport in the world. Legal limits are always more conservative than safety limits. If the weather is legal for flight, the weather is safe for flight.
When driving your car, if the speed limit is fifty-five mph, you know you can drive faster than that and still be safe. But in airline operations, the limit, whatever it may be, is the limit—period! Limits are not exceeded in the slightest. Though a pilot could exceed the legal limits somewhat without compromising safety, doing so could mean revocation of the pilot’s license.
Storms
I’m afraid a storm will break something on the plane or make the pilots lose control.
Your airliner is built the same as the planes that fly smack into hurricanes to measure their intensity and track their movement. Anything Mother Nature can dish out, your airliner can handle.
The dispatcher plans the flight taking into consideration all factors, including the possibility of en route storms. While en route, the pilots use radar to scan the area ahead. Storm clouds are shown as green, yellow, or red: green indicates slightly bumpy, yellow moderately bumpy, and red very bumpy. Though the plane could handle even the areas that appear red, passengers would find the ride uncomfortable.
Lightning
Can lightning make a plane crash?
Lightning is not a problem for the plane. You are safe from lightning in your car because you are enclosed in metal and are insulated from the ground by the rubber tires. You are safe in a plane because you are enclosed and insulated from the ground by air.
Static electricity that builds up when walking on a rug can discharge with a pop and a slight shock. In the dark, a flash may be observed. Similarly, static electricity accumulates on the surface of a plane when flying through clouds. The plane is equipped with devices to prevent static electricity buildup. Occasionally, in spite of these devices, static electricity builds up and discharges with a flash and a bang indistinguishable from lightning. Though dramatic, neither a static discharge nor lightning cause damage to the plane other than, in the case of lightning, a superficial mark, usually on a wing tip. It is only by inspecting the plane after landing and finding such a mark that the pilots can tell if the plane had a static discharge or a lightning encounter. When flying at night, lightning miles away can light up the cloud you are in, giving the impression that the lightning is nearby. Unless there is sound accompanying the light, the lightning is not nearby.
Images of airliners falling are based on imagination—your imagination, some reporter’s imagination, some passenger’s imagination reported in the media, or Hollywood’s imagination—not reality. Whatever imagination you have of airliners falling needs to be erased or filed away as fantasy.