cosmomiller

All things designed by man can fail.

FYI "AOA" is Angle of Attack, the angle of relative wind or air to the chord of the wing. Some aircraft have a display for it, some do not as the information is processed in the FMS or flight management system. In the Navy, AOA is extensively referenced for proper airspeeds during all phases of flight including carrier landings and air combat.

Northwest Airlines, merged into Delta, experienced 7 failures of instruments leading to unreliable airspeed indications and other problems for the A330. All recovered without incident. Air France had one (same A330 type) and the flight crew stalled it all the way down into the ocean. There is some very basic air work that seems to be in short supply when an aircraft on a clear day goes down from erroneous instruments. That being said, it does appear the trim system got them to a point of no recovery during manual flight.

This was posted yesterday:

On October 29, Lion Air Flight 610, a Boeing 737 Max 8, impacted the Java Sea approximately 12 minutes after departure 35nm northeast of Jakarta, Indonesia. The Indonesia Civil Aviation Authority reported the aircraft had requested to return to Jakarta. There were 181 passengers and eight crew aboard the aircraft.

The Indonesian National Transportation Safety Committee (NTSC) is leading the investigation as the State of Occurrence and is assisted by a team from the National Transportation Safety Board, Federal Aviation Administration, and Boeing.

The NTSC has indicated that the accident flight experienced erroneous angle of attack (AOA) information.

Today, Boeing issued an Operations Manual Bulletin to all Boeing 737 Max operators stating that an erroneous AOA can cause the pitch trim system to trim the stabilizer nose down when the aircraft is being manually flown.

Revised Boeing Operating Instructions instruct crews, in the event an uncommanded nose-down stabilizer trim is experienced on the 737 Max with any additional indications or effects (listed in the Operations Manual Bulletin), to complete the Runaway Stabilizer Non-Normal Checklist to ensure that the STAB TRIM CUTOUT switches are set to CUTOUT and stay in the CUTOUT position for the remainder of the flight.

The FAA has issued an Emergency Airworthiness Directive to mandate the Boeing Operations Manual Bulletin effective upon receipt.

MsPerky

We fly American a lot. They fly that aircraft and said they had initiated a directive some time ago with regard to the problem. Happy to know that!!

boltonblue

I don't mean this in a demeaning way, Dave but the average person has no idea about the complexity of some moderns systems.
The amount of trivial little things that have to work for the whole system to perform.
For me the scary thing is younger engineers who don;t have the respect of what has come before them. ( for the record I'm sure the same was said of me.)
We have a term called system of systems. It addresses the hierarchy of not only all of the components but all of the assumptions made about performance.
A jet will literally have millions of requirements. No Single person will know them all.
The Chief Engineer and his team have to be able to understand them all covering all of the disciplines.
Thermodynamics, electrical,which covers power systems, control systems, communications and computers, mechanical and all of it's disciplines.
Fatigue analysis, stress analysis materials human factors ( so they can squeeze in yet another row) logistics and life cycle planning.
training and simulators. software controls which will have millions of lines of code. and the list goes on and on.

and it all has to be perfect every flight, every time.
including the buffoons who taxi into runway pylons and walls before they take off.

I have an acquaintance who has the patent on the zero G oiling system for one of the jet engines.
It keeps lubrication oil flowing in the engine if the plane inverts....something they are never supposed to do but it is a requirement.
why? because $#it happens.