CHICAGO — THE government's partial grounding of a commuter aircraft due to a possible design flaw reduces the likelihood that human error was responsible for an October plane crash.
The fatal crash sparked renewed calls for tougher upkeep and oversight standards for US commuter airlines, which have an overall accident rate roughly double that of major carriers, federal statistics show. The latest findings indicate, however, that lax maintenance or some other human error was not a prime factor in this case.
``You can't use the ATR [the plane produced by the French-Italian consortium Avions de Transport Regional] to make the argument that commuters are less safe,'' says Julie Beal, director of Public Affairs for the National Transportation Safety Board (NTSB).
The Federal Aviation Administration (FAA) on Friday ordered all ATR-72 and ATR-42 turboprops grounded in icing conditions.
The impact of the ban is major because ATR-72 and ATR-42 turboprops represent 15 percent of all seats on US regional carriers, according to the Regional Airline Association. Nine regional airlines operate the planes nationally, including the St. Louis-based Trans World Express and Continental Express in Newark, N.J. Thousands of travelers in Chicago and across the country have already had plans disrupted by the FAA order.
The flight ban followed weeks of tests conducted on the planes after an American Eagle ATR-72 crashed near Roselawn, Ind., on Oct. 31 killing all 68 people aboard. Simulated tests conducted in France found that certain formations of ice placed toward the end of one wing could cause severe control problems in the planes, according to FAA official Anthony Broderick.
The NTSB early on targeted ice on the wings as a likely cause of the Oct. 31 crash. Although its investigation is still incomplete, the board issued an emergency recommendation on Nov. 7 calling for the grounding of ATRs in icy weather.
In another incident last Tuesday, a smaller ATR-42 made an emergency landing in Chicago after an indicator light showed problems with the plane's de-icing gear. Investigators found a leak in the de-icing mechanism on the right wing.
The growing evidence of an aircraft design flaw jibes with indications that the crash was not caused by human or technical failures stemming from safety standards at American Eagle:
* Since the ATR-72 carries a maximum of 72 passengers, it is required to follow the same strict government safety regulations applied to large commercial aircraft such as the Boeing 747 or MD-11. (Planes with less than 30 seats may follow less stringent rules). American Eagle, a subsidiary of American Airlines, says it operates all its flights according to the stricter standard.
* American Eagle operates the world's biggest regional commuter airline system. Studies show that the largest 20 US commuter airlines, which carry more than half of all commuter passengers, are at least two to three times safer than the country's 180 smaller operations.
* The ATR-72 involved in the crash was nearly new and had only logged 1,300 flying hours since it began service in March. The accident was the first involving an ATR-72 in the United States.
Still, the grounding of the ATRs is creating a logistical nightmare for commuter airlines such as American Eagle, with hundreds of flights cancelled in Chicago and other cities on the eve of the busy holiday travel season.
American Eagle, the largest operator of the ATR-72 and ATR-42 in the country, grounded all of its 41 ATR commuter planes at O'Hare International Airport on Saturday, canceling 290 flights that day alone. The airline plans to move all the ATRs from Chicago to warmer southern cities and replace then with Swedish-built SAAB 340 planes.
Meanwhile, one American Eagle pilot, Steve Fredrick, told the Chicago Tribune he felt vindicated by the FAA directive. Mr. Fredrick came forth after the October accident to warn passengers about what he perceived as the danger of flying ATR planes in icy weather.
Fredrick, who had flown ATRs for five years, was suspended without pay last week. The company has declined to elaborate on why it is disciplining Fredrick.