fredag 21. september 2012

Hydroplaning

Dette går aldri av moten:
Passasjerens bird dog?...... Fotograf ukjent
 
 Ricky Willis had just crested a hill on Ocmulgee East Boulevard on Tuesday morning when he saw a small jet roll through a ditch just a hundred yards in front of him.

"It was pretty fast," said Willis, a sales representative who was out visiting customers. "It hit nose first. It bounced up and crossed the road. The landing gear hit."

Startled, Willis slammed on his brakes in the rain. He'd slowed down by the time he reached the spot where the Beech 400 had crossed the road. By then, the plane had crashed into the woods.

Willis, of Gray, turned his truck around in the road and found a place to park. He saw a woman run into the woods, so he called 911.

He was standing on an embankment between the airport and the road when other cars stopped.

Soon a man, who he later learned had been on the jet, came out from the woods and asked if Willis had seen his bird dog.

Although firefighters had to cut the pilot out of the cockpit, the pilot, co-pilot and passenger were not seriously hurt. The dog also was on the aircraft when it crashed.

The jet was pulled from the woods late Wednesday afternoon and moved to the Macon Downtown Airport, where it will stay until it's moved to a secure facility in Griffin, said Shawn Etcher, a National Transportation Safety Board investigator.

Etcher started examining the wreckage Wednesday, a day after the jet hydroplaned while landing at the airport during a storm.

Etcher said the cockpit voice recorder and a GPS box have been removed from the jet and are on the way to a lab in Washington, D.C., for analysis.

Although the nose of the jet was badly damaged, the rest of the plane is in good enough condition to check for mechanical problems, he said.

"Overall, the airplane is actually in not too bad a shape," Etcher said, "It's good enough to give us a lot of information that we need."

The plane landed during a heavy downpour and hit a puddle of water, according to the sheriff's office.

Etcher said logistics for the airport, including the runway length, will be compared with performance numbers for the jet.

"That's going to be in the days and weeks to come," he said.

The co-pilot, Joel Perkins, told Bibb County deputies the plane was coming in at normal speed in light rain, but there was a lot of water on the runway. After touching down, the plane started to hydroplane and fishtail, according to an incident report released Wednesday.

The pilot, Brian Landers, wrote in a sheriff's office statement that the plane left Charleston, S.C., destined for the Macon Downtown Airport with the Middle Georgia Regional Airport as an alternate.

The plane flew through moderate rain and "received visual" into Macon Downtown Airport. The jet touched down and immediately hydroplaned, according to the statement.

John Dewberry, the owner of the jet, wrote in his statement that the pilot "saved our lives."
Jeg benytter anledningen til å minne om formelen for hydroplaninghastighet:
1. Take your tire pressure in kg / sq cm
2. Divide this by the specific gravity of the contaminant
3. Take the square root of this value
4. Mulitply this by 34
5. The result is the speed of aquaplaning in kts.

 Source: Airbus "Getting to Grips with Aircraft Performance" Section 5.5.2.4, Page 82.

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