Plane & Pilot
Tuesday, February 10, 2009

Icing Awareness

The quantity and quality of information have improved, but icing is ever a deadly foe

ntsbTen years ago, the National Aviation Weather Program Council met in Washington, D.C., to develop ideas that could be turned into practical steps toward reducing the number of weather-related aircraft accidents. Regarding in-flight icing, the group—which included FAA, Department of Defense, NASA, Department of Commerce, Department of Agriculture and NTSB representatives—concluded that better observation systems were needed for detecting icing, and weather forecasts should present icing hazards in clear, easily understood formats.
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The controller then coordinated with Johnstown Tower and received a more current weather observation. At 3:45, the controller advised the pilot that the weather included an overcast cloud layer at 500 feet, temperature of 0 degrees C, dew point of minus-1 degree C and visibility at four miles. A minute later, the controller provided a final vector and cleared the pilot for the ILS runway 33 approach. At 3:49:36, the controller radioed that the plane was established on the localizer, radar service was terminated and the pilot should contact Johnstown Tower on frequency 125.75.

At the time of the accident, the tower was staffed by an ATC supervisor, specialist and trainee. Because neither the pilot nor Cleveland Center had declared an emergency, the trainee was the primary controller, backed by the supervisor. At 3:49:52, the pilot reported that the airplane was on the ILS for runway 33, and the trainee asked the pilot if she was going to execute a missed approach or a full-stop landing. The pilot answered, “It depends if my ice comes off or not...if the ice does not come off, we’re gonna land.” The tower trainee replied, “Roger, and keep me advised.” There were no further transmissions from the pilot.

According to the tower supervisor, just before the airplane broke out of the clouds, he told the trainee to provide the pilot with the current winds. At 3:54:13, the trainee radioed, “Wind check three one zero at 17, gust 21.”

According to the tower supervisor, who was using binoculars, he saw the plane break out of the clouds about 300 feet above the ground, right of course, approximately over taxiway B. The airplane appeared to be turning slightly to the right and climbing, and all three controllers commented that they thought the airplane was executing a missed approach. The supervisor said, “All of a sudden, the airplane made a rapid turn to the left, toward the runway, and began dropping like a rock, just dropping.” The supervisor saw that the landing gear wasn’t down and told the trainee to warn the pilot. At 3:54:21, the trainee radioed, “Check wheels down.”

At 3:54:23, when the airplane was at about 75 to 125 feet, the supervisor radioed, “Go-around, go-around, go-around.” The supervisor then saw the airplane make a “hard” landing about 2,000 feet beyond the runway threshold, on the left side of the runway. He saw a “puff of dust” and thought it had landed half on/half off the runway. He then observed the plane take off again “almost perfectly; it flew straight ahead” for 2,000 to 3,000 feet, and the landing gear was down. The plane then made a right turn “like in a midfield, right closed pattern,” but then made “a steep nosedive into the grass infield.”

According to company records, the pilot had a total of 3,547 flight hours (382 hours with the company). The C-414 was equipped with deicing wing boots, electric propeller deicing and an alcohol system for deicing the windshield. The pilot had contacted the Cleveland Automated FSS to file two flight plans, one for 9,000 feet, the accident flight, and another for 10,000 feet for the return flight from Teterboro to the Milwaukee area. The pilot also received weather briefings for each intended flight. The briefer advised of “moderate icing conditions from the freezing level to 17,000 feet” and “southwest Pennsylvania light to moderate rime icing.” The briefer also reported temperatures in several states and said, “So, pretty much, you can expect ice...from about 2,000 feet, and you’ll have to keep a close eye on it...they just say ‘moderate ice’ now.” The briefer also noted that the lowest freezing level was at 6,000 feet.

Prior to the NTSB’s arrival, the runway had been swept of debris and ice, and airplane remnants near the initial propeller strikes had been removed from the grass, but photos of the runway before it was cleared were provided by an initial responder. According to the responder, he “proceeded to runway 33 and noticed a large amount of ice pieces, which started at the 2,000-foot mark and extended in a ‘V’ pattern approximately for 1,000 feet.” He also noted that the ice pieces ranged in size from “long horizontal pieces to golf ball and baseball sizes.”

The NTSB determined that the accident’s probable cause was the pilot’s improper decision to abort the landing with a damaged plane. Contributing factors were damage from the plane’s impact of the runway, the pilot’s failure to lower the landing gear prior to the landing attempt and the in-flight icing conditions.    

Peter Katz is editor and publisher of NTSB Reporter, an independent monthly update on aircraft accident investigations and other NTSB news. To subscribe, write to: NTSB Reporter, Subscription Dept., P.O. Box 831, White Plains, NY 10602-0831.


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