Monday, February 9, 2015

Do Weather-Related Flight Delays Really Save Lives?

By Jillian MacMath, AccuWeather.com Staff Writer
February 9,2015; 8:27PM,EST
 
 
During major weather events, such as snowstorms and severe weather, the number of flight delays and cancellations in a given day skyrockets. Though they can feel like a nuisance for airline passengers, it begs the question: Do weather-related flight delays really save lives?
Just how safe are passengers when they board a commercial airliner and soar to 30,000 feet?
While weather plays a role in whether your flight takes off on time - or at all - most commercial airliners are equipped to deal with an array of weather situations, according to Steve Abdu, an aviation expert with more than 40 years experience.
Abdu has logged more than 30,000 hours of flight time, and previously served as the captain on a Boeing 777, flying domestically and internationally for a major U.S. airline.
A plane pulls into the gate at JFK International Airport. (AP Photo/Mary Altaffer)
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What Conditions Cause Significant Delays?
Often, delays are caused by what type of flying a pilot is able to do based on the weather, Abdu explained.
There are two ways to fly a plane, the first being visual flying, Abdu explained.
Visual flying is an option when a pilot can take over from controllers and fly the plane by watching what's in front of them.
"The controller doesn't have to stay with you every step of the way. There's less separation between airplanes because the pilot can see what's in front of them," Abdu said.
The second method is instrument flying. During low visibility days, this method is used over visual flying. It allows the plane to, essentially, fly itself. However, under this method, the FAA dictates that fewer planes can be in the sky.
This can lead to ripple-effect delays, forcing passengers to spend hours sitting in airport terminals even in areas where bad weather is not occurring.
"When there are instrument conditions, then they have to maintain more distance between the airplanes, and when that happens it means that there are fewer operations per hour," Abdu said.
When only half as many planes are in operation, as sometimes happens when instrument flying, delays can start to snowball.
Snow flies at Chicago's O'Hare International Airport. (Flickr/Seth Anderson)
How Does Winter Weather Affect a Flight?
Winter weather, itself, would rarely cause a problem for an airplane already in flight. However, it can lead to delays on the ground.
During winter storms, often times deicing procedures need to occur before takeoff, which can delay flight.
"Regulations require that we have clean wings before we take off," Abdu said.
In the air, however, icing is rarely a problem. Commercial airplanes are designed to fly in these conditions.
"[The plane takes] hot compressed air from the engine and runs it out to the wings and it melts the ice."
The same process is done to the intake of the engine, preventing ice from forming and melting that which does form.
What Weather Conditions Make Flying Dangerous?
Various conditions can cause delays, but few make flying dangerous for those on board.
"The main threat would be something that's referred to as a microburst," Abdu said.
A microburst is a downdraft, or sinking air in a thunderstorm, that is less than 2.5 miles in scale. The scale of microbursts and the suddenness of which they occur make them hazardous to aircrafts.
"For an airplane going through that or attempting to go through that, initially your airspeed would climb dramatically," Abdu said.
"But as you get through that downward column of air, eventually that airspeed falls off and leads you in a very precarious position, which is usually in the landing phase, where you do not want to be low and slow."
Several fatal crashes at takeoff and landing have been attributed to the phenomenon in recent decades, including the Delta Flight 191 crash in 1985, which killed more than 130 people and the July 2, 1994 US Airways Crash, which killed 37 on board.
"First and foremost, if you're in an area of thunderstorms, you try and avoid them," Abdu said. Mid-flight, pilots will reroute if unsafe conditions arise.
"....If you get a line of storms, sometimes the best approach is to parallel that line of storms until you find a break in the action," Abdu said.
Following the Delta crash in 1985, the FAA created a training course to teach pilots how to escape if they inadvertently fly into one.
Additionally, Doppler radar has made it much easier to see and avoid microbursts. Some airports also now have instruments which detect the phenomenon by measuring wind shear at ground level.
"Commercial airlines definitely are equipped to deal with most types of weather," he said.
 

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