Storm in Benelux causes near disaster at Schiphol

A couple of days ago, there was severe weather across much of Belgium, the Netherlands, and Luxembourg (Benelux).  This played merry hell with the very dense air traffic in northern Europe, with many flights diverted from their destinations.  One other knock on effect is that bad weather reduces the operations capacity of an airport. An airport  can accommodate half a dozen jet landings in 10 minutes in fair weather might be reduced to only two or three in bad weather. Worse still, bad weather will force missed approaches, further reducing the capacity.

This severe weather lead to some very close calls at Amsterdam’s Schiphol International Airport.

[youtube https://www.youtube.com/watch?v=Nio38kxye-I]

[youtube https://www.youtube.com/watch?v=F9LruOa-hzA]

Wind shear is the phenomenon where a column of air is flowing down from a storm toward the ground. When that column of air hits the ground, it flows outward.

http://www.allweatherinc.com/wp-content/uploads/Microburst.png

What happens is that an aircraft on approach, flying into this outward flow essentially suddenly has a major headwind component, and its indicated airspeed makes a sudden leap, say from 140 knots to 160 knots. Pilots on approach, being very sensitive to maintaining speed for landing, almost instinctively reduce power to reduce speed.* The problem is, as the jet passes through the column, while decelerating, they then encounter a very strong downward force, and worse on the far side, they suddenly find themselves traveling in the same direction of the outflow.  That effectively removes the headwind component, and indeed, the tailwind component results in a sudden drastic drop in indicated airspeed, say from 160 knots to suddenly 120 knots. The problem is, a 737 won’t fly at 120 knots. 

Coupled with the downward vector imparted earlier, and the reduction of power, it is very easy for an airliner to be slammed into the ground well short of the runway, with disastrous consequences. 

I’ll leave it to Spill to describe the proper procedure for pilots that do find themselves in windshear.

The atrocious weather at Schiphol meant that Trasnavia wasn’t the only airliner having trouble that day.

[youtube https://www.youtube.com/watch?v=02ddnGzxNZs?feature=player_embedded]

H/T to Airplane Pictures.
https://twitter.com/iLove_Aviation/status/626207186587287553

*Or worse, the autothrottles most airliners fly approaches with do it for the pilot and the pilot doesn’t immediately grasp that they are flying into windshear.

A-10 Hawg’s New Role As a Storm Chasing Aircraft.

This A-10 is undergoing conversion to a storm chasing aircraft.
This A-10 is undergoing conversion into a storm chasing aircraft.

As retirement looms for the USAF’s A-10 Hawg, the National Science Foundation and Zivko Aeronautics have teamed up in a $13 million dollar project to convert one aircraft into a platform to deploy sensors in thunderstorms.

A computer server system will be installed where the weapons system used to be. The system will use sensors on the wings to detect things like wind speed, pressure and movement of a storm. The information is then sent to researchers working on the ground.

“So they’ll get real time, first-hand knowledge of whatever it is they want to sample,” Schneider said.

The A-10 will be equipped to release small sensors into the storm, similar to what was done in the movie “Twister”. The only difference is the sensors will be released from above the storm instead of below it.

“We’re actually going to drop ours out of the wing tips and the wheel pods,” said Schneider.

Learn more from the video in the article above.

From the National Science Foundation:

Since the retirement of the South Dakota School of Mines and Technology (SDSMT) T-28 in 2005, the storm research community has been without means of obtaining in-situ measurements of storm properties.  In 2010 the National Science Foundation (NSF) took steps to remedy this.  The Foundation decided to sponsor the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) at the Naval Postgraduate School in Monterey, CA, to requisition a Fairchild A-10 from the US Air Force.   A year later, the USAF agreed to lend a mothballed A-10 to the US Navy, to be regenerated, reinforced for storm penetration, instrumented for scientific research, and operated by CIRPAS in collaboration with scientists at SDSMT.

The A-10 is a rugged aircraft deisgned to take a lot of punishment from the battlefield. That same strength will be of value when doing the storm research. From Popular Mechanics:

“Conventional research aircraft avoid these severe storms, so they’re basically outside looking in,” meteorologist and veteran storm-chaser Joshua Wurman of the Center for Severe Weather Research in Boulder, Colo, tells PM. “We want to study the worst weather, but we’re trying to keep the [plane] outside the worst weather. With the A-10, we don’t have that limitation.”

A couple of the Thunderbolt’s targets will be supercell thunderstorms, which birth tornadoes, and mesoscale convective systems, giant storm clusters that can produce thunder and lightning, pounding hail, and damaging winds. Ground-based radar systems can track wind and precipitation in these systems fairly well from a distance. But to understand how temperature and humidity contribute to tornado formation, for example, researchers need to get at the heart of the storm.

The A-10 started off as a platform designed to save lives on the battelfield. It’s an interesting twist the A-10 will now be saving civilian lives in the US.

Git Sum!
Git Sum!