[NEWS ON A PLANE] Ketchikan to Seattle Flight Plummets 30,000 Feet in 8 Minutes! - P.O.W. Report

Wednesday, December 5, 2018

[NEWS ON A PLANE] Ketchikan to Seattle Flight Plummets 30,000 Feet in 8 Minutes!


Flight 64, the evening “milk run” flight through Southeast Alaska that originates in Anchorage, was on the last leg of its journey when pilots were alerted to a possible problem with the air pressure within the plane’s passenger cabin. At the time, the plane — a Boeing 737-700 — was 41,000 feet above Vancouver Island, according to flight tracking service FlightAware.

Records indicate the pilots descended to 10,000 feet within eight minutes of the alarm. The flight continued at 10,000 feet and the pilots declared an emergency, allowing a speedy landing at Seattle-Tacoma International Airport. The flight ended up landing a quarter-hour earlier than scheduled. [..]

The spokeswoman, who responded to questions by email, offered apologies to the passengers aboard the aircraft and said the plane will be removed from service.

She said she could not immediately confirm whether the pressurization warning was a false alarm or an actual cabin depressurization. That will be confirmed when the plane and its onboard data are fully inspected, she said.

The good news is that everyone arrived in Seattle 30 minutes early, that never happens!

In related news;

Boeing to warn 737 MAX operators of a potential instrument failure that could cause the jet to nose-dive

Following the fatal crash of a Lion Air jet in Indonesia last week, Boeing was preparing Tuesday evening to warn all airlines operating its new 737 MAX of the potential for an instrument failure that could result in the plane entering a dangerous dive, according to a person briefed on the bulletin’s details. [...]

Investigators looking into the cause of the Lion Air crash, which killed all 189 passengers and crew, have identified a potential failure of a sensor that tells the pilot and the flight control computer the airplane’s “angle of attack,” which is the angle between the wing of the plane and the flow of air it is moving through.

A plane will have a high angle of attack when climbing. Too high an angle would cause a stall.

The concern caused by the flight pattern and initial investigation of the Indonesian crash is that the sensor may potentially feed false information about this angle to the flight computer, which in turn triggers other errors.

In particular, with the sensor falsely indicating that the nose is too high, when it isn’t, it causes an automatic system response that “trims” the horizontal tail of the plane to begin putting the plane’s nose down.

At the same time, it causes an indicator of the minimum speed to tell the pilot that the plane is near a stall, which also causes the pilot’s control column to shake as a warning. And the airspeed indicators on both sides of the flight deck disagree.

The pilots can use extra force to correct the nose down trim, but the failure condition repeats itself, so that the nose-down push begins again 10 seconds after correcting.

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