个人资料
正文

APNewsBreak: Airspeed systems failed on US planes

(2009-08-07 15:11:53) 下一个

Aug 7, 5:21 PM (ET)

By JOAN LOWY

WASHINGTON (AP) - On at least a dozen recent flights by U.S. jetliners, malfunctioning equipment made it impossible for pilots to know how fast they were flying, federal investigators have discovered. A similar breakdown is believed to have played a role in the Air France crash into the Atlantic that killed all 228 people aboard in June.

The discovery suggests the equipment problems are more widespread than previously believed. And it gives new urgency to airlines already scrambling to replace air sensors and figure out how the errors went undetected despite safety systems.

The equipment failures, all involving Northwest Airlines Airbus A330s, were brief and were noticed only after safety officials began investigating the Air France crash - on a Rio de Janeiro to Paris flight - and two other recent in-flight malfunctions. The failures were described by people familiar with the investigation who spoke only on condition of anonymity because they were not authorized to comment publicly.

While a car's speedometer uses tire rotation to calculate speed, an airplane relies on sensors known as Pitot tubes to measure changing air pressure. Computers interpret that information as speed. And while a car with a broken speedometer might be little more than an inconvenience, many airplane control systems rely on accurate speed information to work properly.

(AP) In this June 14, 2009 file photo, workers unload debris, belonging to crashed Air France...
Full Image
Like the fatal Air France flight, the newly discovered Northwest incidents and the two other malfunctions under investigation all involved planes with sensors made by the European electronics giant Thales Corp. The Air France crash called into question the reliability of the sensors and touched off a rush to replace them.

Many companies, however, simply replaced them with another Thales model. As it became clear the problem was more widespread, Airbus and European regulators told companies to replace at least two of the three sensors on each plane with models made by North Carolina-based Goodrich Corp. The planes are allowed to continue flying while the switch is made.

Thales officials declined to comment. The company has previously said its sensors were made to Airbus specifications.

The Northwest incidents were discovered when Delta Air Lines, which merged with Northwest last year, reviewed archived flight data for its fleet of 32 Airbus A330s, the people close to the inquiry said. All the planes involved landed safely.

Aviation experts said the discovery could provide clues to what caused Air France Flight 447 to crash into the Atlantic en route from Brazil to France on June 1, and what might be done to prevent future tragedies.

French investigators have focused on the possibility that Flight 447's sensors iced over and sent false speed information to the computers as the plane ran into a thunderstorm at about 35,000 feet.

An important part of the investigation focuses on 24 automatic messages the plane sent during its final minutes. They show the autopilot was not working, but it is unclear whether the pilots shut it off or whether it shut down because of the conflicting airspeed readings.

Three weeks after the Air France crash, the U.S. National Transportation Safety Board announced it was investigating two other A330 flights that experienced a loss of airspeed data.

The most recent was on June 23, when a Northwest flight hit rain and turbulence while on autopilot outside of Kagoshima, Japan. According to an NTSB report, speed data began to fluctuate. The plane alerted pilots it was going too fast. Autopilot and other systems began shutting down, putting nearly all the plane's control in the hands of the pilot, something that usually happens only in emergencies.

In May, a plane belonging to Brazilian company TAM Airlines lost airspeed and altitude data while flying from Miami to Sao Paulo, Brazil. Autopilot and automatic power also shut down and the pilot took over, according to an NTSB report. The computer systems came back about five minutes later.

"These two cases we know were dealt with effectively by the crew, and we think this happened in Air France and maybe wasn't dealt with effectively," said Bill Voss, president of the Flight Safety Foundation in Alexandria, Va., an aviation safety think tank.

Morgan Durrant, a spokesman for the only other U.S. airline that operates A330s, US Airways, said it had not seen similar problems in its 11-plane fleet of the jetliners.

Delta/Northwest and US Airways recently completed replacing older Thales tubes with new Thales tubes. The companies say they are now replacing them with Goodrich tubes.

In June, the Air France pilots' unions urged its members to refuse to fly Airbus A330s and A340s unless their Thales sensors had been replaced.

The Federal Aviation Administration hasn't issued a safety directive, but spokeswoman Laura Brown said the agency hopes to have one soon.

(AP) In this June 12, 2009 file photo, debris from the missing Air France flight 447 are put on...
Full Image
 
Google sponsored links
Extreme Fear Of Flying is - our specialty. See free video. Call for immediate help trusted by 7000
www.FearOfFlying.com
 
Anxious? Depressed? OCD? - Dr. Joyce Nash can help. Call now. Visa and Matercard accepted.
www.joycenashphd.com
 


Google sponsored links
 
Coffee Fool Exposed - A shocking secret coffee co's don't want you to know
www.coffeefool.com
 
Control Your Fear © - Quick Relief from Fear Easy Steps Towards Freedom
Stop-Fear.PanicAway.com
 
How to make electricity - Tired of bills? A shocking secret electric co's don't want you 2 know
www.Power4Home.com
 
 



 other us government news    

 APNewsBreak: Airspeed systems failed on US planes 
 Senate confirms new NIH director 
 Airlines flying Airbus A330 and A340 planes 
 US attorney in Alexandria, Va., nominated 
 Ex-top NASA official guilty of ethics violations 
 Wealthy Hollywood producer paid for NKorea flight 
 Audit finds research labs slow to improve security 
 Less snail mail, more red ink at post office 
 Richardson: Freed journalists a win for both sides 
 US judge declines to intervene in UAE trial 


  email this page to a friend


Copyright 2009 Associated Press. All right reserved. This material may not be published, broadcast, rewritten, or redistributed.


[ 打印 ]
[ 编辑 ]
[ 删除 ]
阅读 ()评论 (0)
评论
目前还没有任何评论
登录后才可评论.