About Jeff Masters
By: Dr. Jeff Masters , 6:39 PM GMT on March 05, 2008
A Lufthansa Airbus A320 with 137 people on board nearly crashed at the Hamburg, Germany airport on Saturday, March 1, as the pilot struggled to land the airplane during high winds kicked up by winter storm "Emma". If you don't have a fear of flying, take at look at the remarkable video an amateur photographer captured of the landing. It's been uploaded to LiveLeak.com and YouTube. As seen in the still images captured from the video (Figure 1), the pilot attempted to land the aircraft with a strong crosswind blowing from right to left. The crosswind is so strong that the drift angle of the aircraft (the difference between where the nose is pointed and the actual track of the airplane along the runway) is about 20 degrees. As the pilot touches the wheels down, he kicks the rudder to straighten the airplane out, and at that moment, a strong gust of wind lifts up the right wing, pushing the left wingtip of the aircraft into the runway. The pilot is skillful and lucky enough to avoid having the airplane cartwheel down the runway and explode, and aborts the landing attempt. You can see the blast of the engines kick up a cloud of dust on the left side of the runway as he goes to full throttle for a "go around" (thanks to Jeff Weber of UNIDATA for making the correct analysis of this dust cloud). The plane landed safely on its second attempt. Do you think the passengers were praying during that second landing? I do! Only minor damage was done to the left wingtip, and the plane was back in service by the next day.
Figure 1. Still photo of the Lufthansa jet (left) as it approached the runway. Note sharp angle between the direction the airplane's nose is pointed, and the track it is taking along the length of the runway. Strong winds of 40 mph gusting to 63 mph were observed at the airport that afternoon. Right photo: the left wingtip of the jet scrapes the runway as a big gust of wind hits. Image credit: LiveLeak.com.
The weather that led to the near disaster
The initial press reports indicated that a wind gust of 155 mph hit the aircraft as it tried to land. That sounded rather dubious to me, so I took a closer look at the weather conditions that day. The only way a wind gust of that magnitude could have been generated would be from a powerful microburst flowing out from the base of a severe thunderstorm. The world record strongest thunderstorm microburst occurred on August 1, 1983, when winds of 149.5 mph were clocked at Andrews Air Force Base near Washington D.C., just five minutes after President Reagan landed there aboard Air Force 1. So, a 155 mph wind gust is possible, but it would be a new world record.
Figure 2. Visible satellite image from 10:20 GMT Saturday March 1 2008. Winter storm "Emma", a 960 mb low pressure centered north of Hamburg over Norway, has pushed a cold front through Germany. A strong northwest to west-northwest flow of air coming off the North Sea (red arrows) brought sustained winds of 36 mph, gusting to 56 mph, to Hamburg, Germany. Image credit: University of Bern, Switzerland.
Were there severe thunderstorms near Hamburg on March 1 that could have generated such a wind gust? A powerful low pressure system (Emma) with a central pressure of 960 mb passed to the north of Hamburg, Germany that morning, dragging a strong cold front through in the late morning (Figure 2). After cold frontal passage, the wunderground history page for Hamburg at 12:50 GMT, five minutes before the time of the incident, shows sustained winds of 35 mph, gusting to 56 mph. A temporary wind reading of 40 mph, gusting to 63 mph, also occurred. The temperature was about 45°F, with occasional rain. This is classic post-cold front weather, and is not the sort of environment where severe thunderstorms with strong microbursts occur. Later press reports corrected the 155 mph wind gust, reducing it to 56 mph. Apparently, the aircraft's landing speed was 155 mph. In any case, the plane was operating very near to the maximum crosswinds an Airbus A320 is permitted to land in--38 mph, gusting to 44 mph. There are questions whether air traffic control should have used that runway for landings, and whether or not the pilot should have attempted a landing in those conditions. There is an interesting discussion at the LiveATC.net discussion forum where some pilots weight in on the near-disaster.
Winter storm Emma did considerable damage across Germany. Six people died in weather-related automobile accidents, power was cut to 150,000 homes, and high winds ripped the roof off of a school in Hesse. In neighboring countries, 260 buildings lost their roofs in Poland, flooding collapsed a bridge in Romania, and in the Czech Republic, 92,000 people (about 10 percent of the population) lost power.
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