Tuesday, April 30, 2013

Did Weather Play a Role in the 747 Crash in Afghanistan?


Yesterday morning, a 747 cargo plane crashed on takeoff from Bagram Air Force Base, killing the seven people on board. There is quite a bit of speculation on the internet that weather was involved. While the speculation may be warranted, it is far too soon to know the cause of the crash.

Because of the interest, let's take a look at a few things we do know. The map below shows the location of the base north of Kabul.

The European weather satellite image below, from 1.5 hours after the crash, shows an area of extensive clouds (arrow) with showers and thunderstorms that includes the area around Bagram.

The Aviation Herald has the aviation weather observations (known as "Metars") from Baghram. They reveal there was lightning visible, gusty winds, and shifting winds in the area. The base weather observer was estimating rather than measuring the wind. The array of weather instruments to help detect wind shear we enjoy in the U.S. doesn't exist.

Let me hasten to add that weather may have little or nothing to do with the crash. There are reports cargo may have shifted. That said, we know that wind shear on take off can cause planes to stall aerodynamically and fall from the sky. That occurred in the case of Continental Airlines Flight 426 from Denver to Wichita August 7, 1975. In that case, the thunderstorms were near rather than at the airport and the plane fell from the sky shortly after take off. Fortunately, there were no fatalities.

In the U.S., wind shear-related airline accidents have all but been eliminated. The last was in July of 1994. Tragically, they continue in other parts of the world. I'll report on the progress of this investigation to learn the role, if any, of weather.

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