Of Interest to those who pilot / maintain the B777

[Longtimer]

DOT requires 777 operates to inspect pitch rate sensors
By: JON HEMMERDINGERWASHINGTON DC Source: in 2 hours
A new airworthiness directive issued by the US Federal Aviation Administration requires Boeing 777 operators to inspect and potentially replace the aircraft's dual pitch rate sensors (PRS).

The directive, which applies to 777-200LRs, -300s, -300ERs and 777 freighters, comes in response to reports received by the agency of dual failures of the sensors.

When both sensors fail, the aircraft's primary flight computer transitions from primary to secondary mode, which causes the autopilot to disengage, says the directive, made public by the US Office of the Federal Register on 19 November.

"We are issuing this AD to prevent a dual PRS failure that could cause an automatic disengagement of the autopilot and autoland," says the DOT's directive.

Losing both autopilot and autoland can be dangerous, particularly if it "occurs at low altitude and the flight crew is unable to safely assume control and execute a go-around or manual landing", adds the document.

The directive will be published in the Federal Register tomorrow and becomes effective 35 days later.

The rule will require US operators to inspect, within 60 months, all four PRS on their 777s to determine the sensors' part number.

Then, prior to further flight, operators must replace any PRS with part number 402875-05-01, says the directive.

DOT estimates airlines will spend $170 to inspect each aircraft and $340 to swap parts.

The new requirements come roughly 16 months after a Boeing 777 operated by Asiana crash in San Francisco after the pilots failed to understand complexities of the autopilot systems.

The National Transportation Safety Board pegged crew failures as the ultimate cause, but added that the pilot falsely assumed that the autothrottle was maintaining speed.

The aircraft's speed deteriorated when the autothrottle transitioned to "hold" mode while the flight computer was in "flight-level change mode", a configuration under which the autothrottle does not maintain speed.

The crash led to the death of three passengers.

http://www.flightglobal.com/news/articl ... rs-406268/

[Meatservo]

The autopilot might not work? Short of the wings falling off, this is the worst thing that could possibly happen to a modern jet and its crew. I hope this is fixed right away before there is a rash of stall/spin and landing accidents.

[Duffman]

DOT estimates airlines will spend $170 to inspect each aircraft and $340 to swap parts.

Are there a couple zeros missing on those numbers?

[Meatservo]

DOT estimates airlines will spend $170 to inspect each aircraft and $340 to swap parts.

Are there a couple zeros missing on those numbers?

Nope. They just need to swap co-pilots. That's for the whole month.

[1000 HP]

DOT estimates airlines will spend $170 to inspect each aircraft and $340 to swap parts.

Are there a couple zeros missing on those numbers?

The missing zeros are for Cessna parts..

[hst]

The new requirements come roughly 16 months after a Boeing 777 operated by Asiana crash in San Francisco after the pilots failed to understand complexities of the autopilot systems.

The National Transportation Safety Board pegged crew failures as the ultimate cause, but added that the pilot falsely assumed that the autothrottle was maintaining speed.

The aircraft's speed deteriorated when the autothrottle transitioned to "hold" mode while the flight computer was in "flight-level change mode", a configuration under which the autothrottle does not maintain speed.

The crash led to the death of three passengers.

The last part of the article has absolutely nothing to do with the potential PRS failures and resultant FAA AD.

That quote above has everything to do with 3 pilots allowing an aircraft to fly them instead of being professional pilots by actively monitoring the flight profile and react accordingly. They were just going along for the ride until it was too late.

[dashx]

http://en.wikipedia.org/wiki/Eastern_Ai ... Flight_401

http://en.wikipedia.org/wiki/Colgan_Air_Flight_3407

the pilots failed to understand complexities of the autopilot systems.

Did they?